Introduction:Q fever, caused by Coxiella burnetii, is a zoonotic disease of global relevance with domestic ruminants as the main reservoirs. Serological diagnosis, especially enzyme-linked immunosorbent assay (ELISA), often suffers from limited sensitivity and specificity due to antigenic variability and cross-reactivity. Scientific goal:In this study, a combined proteomic and literature research approach was used to identify immunoreactive proteins and predict linear B-cell epitopes as alternative diagnostic targets. Methods:Total protein extracts of a C. burnetii field isolate from sheep were separated by two-dimensional gel electrophoresis, and immunoreactive proteins were detected by Western blotting using pooled sheep sera obtained from various flocks with known Q fever status. Immunoreactive proteins were identified by LC-MS/MS and used for linear B-cell epitope prediction for peptide synthesis. Peptides (n = 30) were initially screened by fluorescent ELISA against nine field serum pools (90 individual sera), and the most promising peptides (n = 15) were individually tested with 79 single sera. Diagnostic performance was assessed by receiver operating characteristic (ROC) analysis and by a multi-peptide rule ("positive if ≥1 peptide reactive"). Results:A total of 156 seroreactive proteins, including 51 previously reported antigens, were detected, among others, Com1, CBU_0482, and Mip. Although the selected 15 peptides showed a specific reaction with pooled sera, they showed limited diagnostic performance with an area under the curve (AUC) of 0.5-0.7 when using single serum samples (n = 79). Multi-peptide combinations (6-8 peptides) increased sensitivity (Se) to 80% and specificity (Sp) to 75%. Discussion:Although single peptides lacked discriminatory power, multi-epitope combinations reached acceptable accuracy and may be used as a complementary tool for commercial ELISAs. However, larger bioinformatic approaches and validation studies are required to identify specific peptides of high diagnostic accuracy.

C. burnetii is a Gram-negative, obligate intracellular bacterium and the causative agent of Q fever. The disease is either asymptomatic or manifests as a mild flu-like illness, but pneumonia or hepatitis might also occur. In most cases, the infection is self-limiting and the pathogen is cleared. In a small percentage of patients, the host immune system fails to eliminate the pathogen, potentially allowing the development of chronic Q fever months or even years after primary infection. The elimination of the bacteria, and thereby prevention of disease onset, would require an inflammatory response. Inflammasomes are multimeric protein complexes that induce a pro-inflammatory response to combat pathogens. Here we show that C. burnetii fails to induce strong activation of the non-canonical inflammasome, independently of its type IVB secretion system. However, the pathogen is unable to prevent external activation of the non-canonical inflammasome, which subsequently results in a reduction of the bacterial burden. Importantly, the acylation pattern of lipid A was identified to be involved in avoiding the activation of the non-canonical inflammasome. C. burnetii harbors a tetra-acylated lipid A. Modification of the C. burnetii lipid A to penta-/hexa-acylation in a small subpopulation resulted in increased secretion of IL1β and reduced bacterial load. Together, these results suggest that the acylation pattern of lipid A constitutes an important immune evasion strategy of C. burnetii by failing to activate the non-canonical inflammasome. In addition, evidence was provided that oxygen limitation arrests activation of the NLRP3 inflammasome in murine BMDM, which might prevent efficient elimination of bacteria under hypoxic conditions, such as in granulomas or in inflamed tissue.

Background/Objectives: The detection of anti-Coxiella antibodies using serological methods is essential for identifying exposed ruminants and preventing this important zoonotic disease in livestock. In recent years, numerous attempts have been made to increase diagnostic performance as well as simplify the production of serological assays. Commercially available tests often use whole-cell antigens, which can decrease specificity and require high-level biosafety facilities for manufacturing. The aim of this work was to produce three Coxiella burnetii (C. burnetii) antigens in recombinant form and assess them for the detection of anti-Coxiella antibodies in ruminants. Methods: Three recombinant C. burnetii antigens (Com-1, MceB, AdaA) were selected among immunodominant antigens and produced in a heterologous system (Escherichia coli). Following purification, the proteins were utilized to coat ELISA plates and evaluated for seroreactivity against sera from both negative and positive cattle. Results: Com-1 demonstrated the greatest agreement with the commercial test, albeit moderate. MceB exhibited nonspecific reactivity against a large number of sera, while the AdaA showed reactivity against only a few positive sera. Conclusions: Our findings are consistent with previous research, indicating that utilizing a single antigen to identify exposed animals is unfeasible with current knowledge, most likely due to the complex immunological response following C. burnetii infection in cattle. Consequently, it is critical to continue testing and identifying immunoreactive antigens in order to further investigate them and, potentially, select the most appropriate.

Coxiella burnetii, the causative agent of Q fever, poses a significant public health concern worldwide. Diagnosis primarily relies on serological tests. Traditional antigen production methods, typically involving embryonated hen eggs, are labor-intensive, costly, and require biosafety level 3 facilities. In this study, we tested inactivated whole-cell antigens (SAP9 and NMII/AP9) from C. burnetii strains grown in axenic media, offering a safer and more efficient alternative to egg-based production. These antigens were validated using an in-house ELISA method against human patient sera, demonstrating high sensitivity and specificity comparable to ELISA and to the Gold Standard, IFA commercial kits. Notably SAP9 and NMII/AP9 antigens showed no cross-reactivity with intracellular pathogens that cause illness with similar symptoms. This approach represents significant advancement in diagnostic antigen production for Q fever, facilitating cost-effective epidemiological studies and enhancing laboratory safety.

OBJECTIVES:Hepatopathy of the steatosis type, splenopathy, and a hypoechoic enlarged gallbladder on abdominal ultrasonography are indications of sudden inflammation affecting the abdominal region. Such a clinical picture due to Q fever is common. However, infectious etiologies for primary mesenteric adenitis are rare. METHODS:A complete biochemistry and clinical examination of the patients, followed by a spectrum of serological and molecular biological tests were performed to detect a causative agent of a very serious, highly infectious illness. RESULTS:Here we report two exceptional cases of Q fever. Physical examination at the time of hospitalization revealed malaise, which was primarily manifested by temperature >38°C. Both patients presented overlapping clinical and laboratory parameters, an elevated lymphocyte, and liver enzyme levels, and high C-reactive protein. The diagnosis of "query" hepatopathy, enlarged gallbladder, splenomegaly and newly, mesenteric adenitis was confirmed by computed tomography scan of the abdomen and pelvis. Serological examination and molecular detection of the pathogen confirmed Coxiella burnetii as the causative agent. CONCLUSIONS:We recommend Q fever be considered not only in cases of acute hepatopathy, enlarged gallbladder and spleen, but also on the occurrence of mesenteric adenitis.

Diagnosis of rickettsial infections is challenging due to nonspecific clinical symptoms and limitations of current diagnostic methods. Molecular assays allow early detection but are limited by cost and technical demands, whereas conventional serological tests often exhibit cross-reactivity and low sensitivity during the early stages of infection. This study aimed to develop and evaluate a recombinant-antigen sandwich ELISA for improved antibody detection against Rickettsia spp. Three Rickettsia akari proteins, rGroEL, rDnaK, and rA8GP63 (uncharacterized protein), were produced and validated for immunogenicity. The assay was evaluated using 94 patient serum samples, including those with positive, negative, and unknown clinical course. The optimized ELISA demonstrated high reproducibility, with IgG sensitivity of 89.47–95.39% and specificity of 90%. IgM detection, also assessed, showed lower sensitivity (42.11–82.89%) but maintained strong specificity (83.33%). The diagnostic performance was comparable to that of a commercial indirect immunofluorescence assay, with no cross-reactivity detected in sera from patients with unrelated infections. rDnaK and rA8GP63 represent newly explored diagnostic candidates. These findings highlight the potential of this recombinant protein-based ELISA as an accessible, sensitive and specific diagnostic tool, with a meaningful clinical impact for improving the early and accurate detection of rickettsial infections.

In this study, we conducted an extensive investigation of the biodegradation capabilities and stress response of the newly isolated strain Pseudomonas veronii SM-20 in order, to assess its potential for bioremediation of sites contaminated with polycyclic aromatic hydrocarbons (PAHs). Initially, phenotype microarray technology demonstrated the strain’s proficiency in utilizing various carbon sources and its resistance to certain stressors. Genomic analysis has identified numerous genes involved in aromatic hydrocarbon metabolism. Biodegradation assay analyzed the depletion of phenanthrene (PHE) when it was added as a sole carbon and energy source. We found that P. veronii strain SM-20 degraded approximately 25% of PHE over a 30-day period, starting with an initial concentration of 600 µg/mL, while being utilized for growth. The degradation process involved PHE oxidation to an unstable arene oxide and 9,10-phenanthrenequinone, followed by ring-cleavage. Comparative proteomics provided a comprehensive understanding of how the entire proteome responded to PHE exposure, revealing the strain’s adaptation in terms of aromatic metabolism, surface properties, and defense mechanism. In conclusion, our findings shed light on the promising attributes of P. veronii SM-20 and offer valuable insights for the use of P. veronii species in environmental restoration efforts targeting PAH-impacted sites.

Haemosporidians are a group of vector-borne parasites belonging to the order Haemosporida. These parasites infect avian hosts and require blood-sucking insects (Diptera) for transmission. The occurrence and diversity of haemosporidian parasites are shaped primarily by the specificity of the parasite and the susceptibility of the host/vector. In this study, the presence and distribution of haemosporidians in blood samples from birds in urbanized and natural habitats were estimated using microscopic and molecular approaches. Birds in urbanized habitats were infected with four different species of Plasmodium, P. relictum, P. vaughani, P. matutinum, and P. circumflexum, and one species of Haemoproteus, H. parabelopolskyi, and Leucocytozoon sp. The species H. attenuatus, H. concavocentralis, H. minutus, H. pallidus, H. noctuae, and H. tartakovskyi were additionally identified in birds in natural habitats. Typically, juvenile birds are essential markers of parasite species transmitted in the study area. The juveniles in the urbanized habitats carried P. relictum, P. vaughani, P. circumflexum, H. parabelopolskyi, and Leucocytozoon species. The most abundant parasite was H. parabelopolskyi, which was found in both habitat types. The prevalence of Haemoproteus/Plasmodium species determined by nested PCR in birds in natural habitats (43.80%; 53/121) was significantly greater than that in birds in urbanized habitats (21.94%; 43/196) (p < 0.05). There was no significant difference in the infection rate of Leucocytozoon sp. between the habitat types (p > 0.05; 10/121 vs. 19/196).

Spontaneous tumor regression is a recognized phenomenon across various cancer types. Recent research emphasizes the alterations in autoantibodies against carbonic anhydrase I (CA I) (anti-CA I) levels as potential prognostic markers for various malignancies. Particularly, autoantibodies targeting CA I and II appear to induce cellular damage by inhibiting their respective protein's catalytic functions. Our study illuminates the profound impact of anti-CA I autoantibodies from patient serum on the esterase activity of human CA I, exhibiting inhibitory effects akin to the acetazolamide inhibitor. Concurrently, our newly synthesized mouse monoclonal IgG antibody, mAb 2B8, against human CA I showcased a potent inhibitory action. An in-depth exploration into mAb 2B8 ' s binding dynamics with its target enzyme was undertaken. Leveraging epitope extraction and phage display library techniques, we identified the amino acid sequence DFWTYP (positions 191-196 of CA I) as crucial for mAb 2B8 ' s interaction. In 3-D structural analysis, this sequence is spatially adjacent to a previously identified epitope (DFWTYP) that interacts with patient-derived autoantibodies. Critically, mAb 2B8 demonstrated an ability to infiltrate eukaryotic cells, engaging specifically with its intracytoplasmic target. This positions mAb 2B8 as a promising model for future studies aimed at tumor cell eradication.

A total of, 78 Clostridium septicum (CLSE) isolates were screened for genes encoding: α‐toxin, flagellin, and resistance to vancomycin ( VANg ). The isolates were also tested for their ability to form biofilm and their antibiotic susceptibility. All isolates were positive for α‐toxin and flagellin genes. However, only 19 isolates (24.3%) showed prevalence for VANg . We observed the strongest capacity to form a biofilm (100%) in isolates from patients with oncologic or septic and febrile diagnoses. This percentage was also very high in patients with colitis and gastrointestinal hemorrhage (72.7%). No less than 43 isolates showed antibiotic resistance, and 21 were multidrug‐resistant (MDR). Interestingly, our studies showed a correlation between antibiotic resistance and biofilm formation. A statistically significant difference was observed between biofilm‐forming MDR isolates and those with low/no biofilm‐forming ability. However, the most impressive observation was the correlation with mortality rate. While the overall mortality rate for CLSE infections was 16.7% (13/78), the mortality rate for patients infected with MDR isolates forming biofilm moderately or strongly reached 38.1% (8/21). This number increased even further when only infections with the biofilm‐forming VANg ‐positive isolates were considered (61.5%; 8/13). Therefore, the ability of a VANg ‐positive CLSE isolate to form a biofilm has been suggested as a biomarker of poor prognosis.

Drought is among the most limiting factors for sustainable agricultural production. Water shortage at the onset of flowering severely affects the quality and quantity of grain yield of bread wheat (Triticum aestivum). Herein, we measured oxidative stress and photosynthesis-related parameters upon applying transient drought on contrasting wheat cultivars at the flowering stage of ontogenesis. The sensitive cultivar (Darunok Podillia) showed ineffective water management and a more severe decline in photosynthesis. Apparently, the tolerant genotype (Odeska 267) used photorespiration to dissipate excessive light energy. The tolerant cultivar sooner induced superoxide dismutase and showed less inhibited photosynthesis. Such a protective effect resulted in less affected yield and spectrum of seed proteome. The tolerant cultivar had a more stable gluten profile, which defines bread-making quality, upon drought. Water deficit caused the accumulation of medically relevant proteins: (i) components of gluten in the sensitive cultivar and (ii) metabolic proteins in the tolerant cultivar. We propose specific proteins for further exploration as potential markers of drought tolerance for guiding efficient breeding: thaumatin-like protein, 14-3-3 protein, peroxiredoxins, peroxidase, FBD domain protein, and Ap2/ERF plus B3 domain protein.

Haemosporidians are a group of vector-borne parasites belonging to the order Haemosporida. They infect avian hosts and require blood-sucking insects (Diptera) for their transmission. The occur-rence and diversity of haemosporidian parasites are shaped primarily by the specificity of the parasite and the susceptibility of the host/vector. In this study, the presence and distribution of haemosporidians in blood samples from birds in urbanized and natural habitats were estimated using microscopic and molecular approaches. Birds in urbanized habitats were infected with four different species of Plasmodium: Plasmodium (Haemamoeba) relictum, P. (Novyella) vaughani, P. (H.) matutinum, P. (G.) circumflexum, two different species of Haemoproteus: Haemoproteus (Parahaemo-proteus) majoris, H. (P.) parabelopolskyi, and Leucocytozoon sp. The species H. (P.) balmorali, H. (P.) concavocentralis, H. (P.) minutus, and H. (P.) pallidus were additionally identified in birds in natural habitats. Typically, juvenile birds are essential markers of parasite species transmitted in the study area. The juveniles in the urbanized habitats carried the P. (H.) relictum, P. (N.) vaughani, P. (G.) circumflexum, H. (P.) parabelopolskyi, H. (P.) majoris, and Leucocytozoon species. The most abundant parasite was H. (P.) parabelopolskyi, which was found in both types of habitats. The prevalence of the Haemoproteus and Plasmodium species in birds in natural habitats (in totally 43.80%) was sig-nificantly higher than that in birds in urbanized habitats (in totally 21.94%) (p < 0.05), also in spring. There was no statistically significant difference between types of habitats for total infection rates with Leucocytozoon sp. (p > 0.05), neither overall nor in the spring.

Rickettsial infections of the central nervous system (CNS) are manifested by severe neurological symptoms and represent a serious life-threatening condition. Despite the considerable health danger, only a few studies have been conducted focusing on the pathogenesis induced by Rickettsia sp. in CNS. To investigate the signaling pathways associated with the neurotoxic effects of rickettsiae, we employed an experimental model of cerebrocortical neurons combined with molecular profiling and comprehensive bioinformatic analysis. The cytopathic effect induced by Rickettsia akari and Rickettsia slovaca was demonstrated by decreased neuronal viability, structural changes in cell morphology, and extensive fragmentation of neurites in vitro. Targeted profiling revealed the deregulation of genes involved in the neuroinflammatory and neurotoxic cell response pathways. Although quantitative analysis showed differences in gene expression response, functional annotation revealed that the biological processes are largely shared between both Rickettsia species. The identified enriched pathways are associated with cytokine signaling, chemotaxis of immune cells, responses to infectious agents, interactions between neurons, endothelial and glial cells, and regulation of neuronal apoptotic processes. The findings of our study provide new insight into the etiopathogenesis of CNS infection and further expand the understanding of molecular signaling associated with neuroinvasive Rickettsia species.

A total of, 78 Clostridium septicum (CLSE) isolates were screened for genes encoding: α-toxin, flagellin, and resistance to vancomycin ( VANg ). The isolates were also tested for their ability to form biofilm and their antibiotic susceptibility. All isolates were positive for α-toxin and flagellin genes. However, only 19 isolates (24.3%) showed prevalence for VANg . We observed the strongest capacity to form a biofilm (100%) in isolates from patients with oncologic or septic and febrile diagnoses. This percentage was also very high in patients with colitis and gastrointestinal hemorrhage (72.7%). No less than 43 isolates showed antibiotic resistance, and 21 were multidrug-resistant (MDR). Interestingly, our studies showed a correlation between antibiotic resistance and biofilm formation. A statistically significant difference was observed between biofilm-forming MDR isolates and those with low/no biofilm-forming ability. However, the most impressive observation was the correlation with mortality rate. While the overall mortality rate for CLSE infections was 16.7% (13/78), the mortality rate for patients infected with MDR isolates forming biofilm moderately or strongly reached 38.1% (8/21). This number increased even further when only infections with the biofilm-forming VANg -positive isolates were considered (61.5%; 8/13). Therefore, the ability of a VANg -positive CLSE isolate to form a biofilm has been suggested as a biomarker of poor prognosis.

Short-chain fatty acids (SCFAs) are the main metabolites produced by bacterial fermentation of non-digestible carbohydrates in the gastrointestinal tract. They can be seen as the major flow of carbon from the diet, through the microbiome to the host. SCFAs have been reported as important molecules responsible for the regulation of intestinal homeostasis. Moreover, these molecules have a significant impact on the immune system and are able to affect inflammation, cardiovascular diseases, diabetes type II, or oncological diseases. For this purpose, SCFAs could be used as putative biomarkers of various diseases, including cancer. A potential diagnostic value may be offered by analyzing SCFAs with the use of advanced analytical approaches such as gas chromatography (GC), liquid chromatography (LC), or capillary electrophoresis (CE) coupled with mass spectrometry (MS). The presented review summarizes the importance of analyzing SCFAs from clinical and analytical perspective. Current advances in the analysis of SCFAs focused on sample pretreatment, separation strategy, and detection methods are highlighted. Additionally, it also shows potential areas for the development of future diagnostic tools in oncology and other varieties of diseases based on targeted metabolite profiling.

Although the cat flea, Ctenocephalides felis, has been identified as the primary vector of Rickettsia felis, additional flea, tick, mite, and louse species have also been associated with this bacterium by molecular means; however, the role of these arthropods in the transmission of R. felis has not been clarified. Here, we succeeded in culture isolation of R. felis from a host-seeking castor bean tick, Ixodes ricinus, the most common tick in Slovakia. The bacterial isolation was performed on XTC-2 cells at 28 °C using the shell-vial technique. An evaluation of the growth properties was performed for both the XTC-2 and Vero cell lines. We observed R. felis in the infected host cells microscopically by Gimenez staining and immunofluorescence assay. The R. felis isolate was purified by gradient ultracentrifugation and visualized by electron microscopy. Fragments of the genes gltA, ompA, ompB, htrA, rpoB, sca4, rffE, and rrs were amplified and compared with the corresponding sequences of the type strain URRWXCal2 and other R. felis culture -isolated strains. We did not detect any nucleotide polymorphisms; however, plasmid pRFδ, characteristic of the standard strain, was absent in our isolate. Herein, we describe the first successful isolation and characterization of a tick-derived R. felis strain "Danube", obtained from an I. ricinus nymph.

This work deals with the purification of an essential therapeutic protein, recombinant human erythropoietin (rhEPO). The source of rhEPO was the post-harvest medium from the cultivation of recombinant human embryonic kidney cell 293 line (HEK 293) with the protein concentration in the medium of 1.9 mg/mL and the rhEPO fraction of only 2.5%. The medium was directly used for chromatographic separation without any previous pre-treatment. A three-step chromatographic procedure was designed based on the results of both column and batch adsorption/desorption experiments. In the first chromatographic separation step, a multimodal adsorbent with cation exchange group, Capto MMC, was used. Many impurity proteins were removed in the breakthrough during the column loading. Effective desorption of rhEPO from this matrix was achieved using 1 M arginine. RhEPO purity of the intermediate product reached 27%. A hydrophobic interaction chromatography adsorbent, Capto Phenyl, was used in the second purification step. Elution was carried out efficiently, using 30% isopropanol and recovering 95% of rhEPO, which was further purified by cation-exchange chromatography using Fractogel EMD SE HiCap. The designed purification process eliminated over 99% of impurity proteins contained in the HEK post-harvest cultivation medium, resulting in an overall purification factor of about 40.

We have observed the spontaneous tumour regression in four patients (breast cancer, Hodgkin's disease, non-Hodgkin's lymphoma and Ewing's sarcoma) who had relapsed/progressed after high-dose chemotherapy (HDC) and autologous haematopoietic stem cell transplantation (ASCT).1 Patients' blood counts strongly resembled the blood counts in aplastic anaemia (aplastic anaemia (AA)-like syndrome). Moreover, some of these patients' morphology of the bone marrow trephine biopsies was identical to the AA picture. It should be noted that in some patients who were treated by conventional chemotherapy only, a similar phenomenon has been observed, too (Lakota J, unpublished observation). In a provoking paper,2 the authors proposed that the autoimmune (anti-tumour) activity against present malignancy also operates against haematopoietic stem cells. The final clinical and laboratory pattern in these patients is present as acquired aplastic anaemia (AA). This pathophysiological mechanism could explain pancytopenia, which frequently occurs in patients with haematological as well as non-haematological malignancies. The conclusion would be that pancytopenia which is present in AA or AA-like syndrome reflects an ongoing immune reaction against underlying malignancy.2 By analysis of the sera of patients with spontaneous tumour regression and (AA)-like syndrome, we have shown that they contain antibodies against carbonic anhydrase I.3 These antibodies were polyclonal. Mapping of carbonic anhydrase isoform I (CA I), we detected four linear epitopes of CA I enzyme (DGLAV, NVGHS, SLKPI and SSEQL).4 We have analysed the sera of bona fide AA patients too. Anti-CA I (auto)antibodies were detected in 38% of patients. Their presence was associated with poor response to ATG treatment (complete response 14%), short long-term survival (36% at ten years) in contrast to antibody-negative patients (complete response 64% and ten-year survival 64%, overall p-value = 0.003).5 After the epitope mapping, the anti-CA I antibodies in this group of patients (bona fide AA) recognized the same linear candidates CA I epitopes—DGLAV, NVGHS, SLKPI and SSEQL.6 Antibodies against CA I have been presented in some autoimmune diseases, for example, systemic lupus erythematosus, Sjögren's syndrome, autoimmune/idiopathic chronic pancreatitis, connective tissue diseases and other rheumatic diseases (reviewed previously in Ref. [6]). Crohn's disease and ulcerative colitis ((autoimmune) inflammatory bowel diseases (IBD)) are characterized by an inflammation of the large and/or small intestine. In 2012, the group from Ehime University (in a murine model) identified CA I as a dominant protein of faecal extracts (called caecal bacterial Ag (CBA)) which was related to the pathogenesis of IBD. Furthermore, the researchers established a therapeutic IBD approach where they used Ag-pulsed regulatory dendritic cells (Reg-DCs).7 First, they induced colitis by transfer of CD4+ CD25- T cells which were obtained from BALB/c mice and were transferred into SCID mice. Ag (ie CA I)-pulsed Reg-DCsCAI induced the differentiation of regulatory T cells and blocked the progression of the colitis. The authors concluded that Reg-DCsCBA inhibited the progression of colitis which has been induced by CD4+ CD25- T cells and that CA I, a central antigen of CBA, had an essential role in suppressing the development of colitis.7 In a more recent paper, the group from Ehime University has shown that oral administration of CA I was able to induce antigen-specific immune tolerance and generated Foxp3+ CD4+ CD25+ Tregs cells. This treatment protects from intestinal inflammation in a murine model.8 (The mechanism of oral tolerance is defined as the inhibition of the immune response to a specific antigen which can be induced in an antigen-specific manner. In general, these effects are not limited to the local immunity only ie within the gut. Oral tolerance ameliorates autoimmune diseases, such as diabetes, multiple sclerosis, rheumatoid arthritis and uveitis. It does not have significant side effects).9 Finally, Yagi et al10 clearly showed that the T-cell CA I epitope peptide interacts with MHC class II molecules that CA I 58-73 peptide-pulsed Reg-DCs protects mice with experimental colitis, and that Reg-DCsCA I 58-73 induces Ag-specific Tregs. Interestingly, the murine CA I 58-73 fragment (KEIVNVGHSFHVIFDD) shows high sequence similarity (81.3%) with human CA I 58-73 fragment (KEIINVGHSFHVNFED). As it has been previously shown,6 there has been an epitope overlap of the antibodies in (AA)-like anaemia syndrome and the antibodies in bona fide AA (ie DGLAV, NVGHS, SLKPI and SSEQL). Analogous (albeit one) epitope overlap exists in the murine CA I 58-73 fragment, which is 100% homologous with the human epitope—NVGHS. The murine CA I 58-73 fragment protects mice with experimental colitis in a murine model for autoimmune IBD. On the other hand, the human fragment (NVGHS) acts as the target epitope of the antibodies against carbonic anhydrase I in patients with bona fide AA and (AA)-like syndrome. Aplastic anaemia (AA)-like syndrome has been observed only in patients who relapsed/progressed after HDC and ASCT and achieved spontaneous tumour regression (ie without any further treatment). The epitope 'alignment' in these cases is not only surprising, but it is also challenging. Will we go further, prepare monoclonal therapeutic antibodies, and possibly will be able to treat a wide variety of malignant tumours? This work was supported by the grant APVV 18-0340 and Foundation for Cell Transplantation. The authors confirm that there is no conflict of interest. Lenka Minichova: Data curation (equal); Formal analysis (equal); Project administration (equal). Ludovit Skultety: Data curation (equal); Formal analysis (equal); Project administration (equal). Jan Lakota: Conceptualization (lead); Data curation (equal); Formal analysis (equal); Funding acquisition (lead); Project administration (equal).

Ticks are medically important hematophagous ectoparasites transmitting pathogens such as Borrelia, Rickettsia, Babesia, Anaplasma, and Coxiella species that may seriously affect the health of animals and humans. More than a million cases of rickettsiosis, anaplasmosis, and Q fever occur annually worldwide, often in farmers or other occupationally exposed people. Despite the confirmed presence of the causative agents in endemic areas, the attention to these intriguing illnesses is frequently neglected in many countries, including Slovakia. We performed serological and molecular analyses of 403 human sera and 118 blood samples obtained from Slovak patients in the last decade. Herein, we describe seven particular cases to illustrate how clinicians and public health professionals are performing laboratory diagnostic work together to monitor the circulation of rickettsiae and rickettsia-like pathogens and solve health challenges associated with these infections. The results of laboratory testing were related to the symptoms of the diseases and possible tick infestations. Fever and erythema or rash were commonly reported in the cases of rickettsial infections, which were confirmed by the presence of IgM anti-SFGR antibodies and PCR assay positive for either Rickettsia helvetica, Rickettsia raoultii, or Rickettsia sp. On the other hand, an acute Q fever was commonly associated with fever and close contact with livestock or their products. Additionally, for the first time in Slovakia, we described a case with the presence of Anaplasma phagocytophilum DNA in human patient's blood for 47 days. In conclusion, we assume that effective surveillance of rickettsioses and Rickettsia-like infections is essential for public health. It certainly contributes to better prevention and management of these communicable diseases.