Background: X-linked agammaglobulinemia is an inherited immunodeficiency recognized since 1952. In spite of seven decades of experience, there is still a limited understanding of regional differences in presentation and complications. This study was designed by the Primary Immunodeficiencies Committee of the World Allergy Organization to better understand regional needs, challenges and unique patient features. Methods: A survey instrument was designed by the Primary Immunodeficiencies Committee of the World Allergy Organization to collect both structured and semi-structured data on X-linked agammaglobulinemia. The survey was sent to 54 centers around the world chosen on the basis of World Allergy Organization participation and/or registration in the European Society for Immunodeficiencies. There were 40 centers that responded, comprising 32 countries. Results: This study reports on 783 patients from 40 centers around the world. Problems with diagnosis are highlighted by the reported delays in diagnosis>24 months in 34% of patients and the lack of genetic studies in 39% of centers Two infections exhibited regional variation. Vaccine-associated paralytic poliomyelitis was seen only in countries with live polio vaccination and two centers reported mycobacteria. High rates of morbidity were reported. Acute and chronic lung diseases accounted for 41% of the deaths. Unusual complications such as inflammatory bowel disease and large granular lymphocyte disease, among others were specifically enumerated, and while individually uncommon, they were collectively seen in 20.3% of patients. These data suggest that a broad range of both inflammatory, infectious, and autoimmune conditions can occur in patients. The breadth of complications and lack of data on management subsequently appeared as a significant challenge reported by centers. Survival above 20 years of age was lowest in Africa (22%) and reached above 70% in Australia, Europe and the Americas. Centers were asked to report their challenges and responses (n = 116) emphasized the difficulties in access to immunoglobulin products (16%) and reflected the ongoing need for education of both patients and referring physicians. Conclusions: This is the largest study of patients with X-linked agammaglobulinemia and emphasizes the continued morbidity and mortality of XLA despite progress in diagnosis and treatment. It presents a world view of the successes and challenges for patients and physicians alike. A pivotal finding is the need for education of physicians regarding typical symptoms suggesting a possible diagnosis of X-linked agammaglobulinemia and sharing of best practices for the less common complications.

Donor-specific antibodies against Glutathione S-transferase T1 (GSTT1) have been associated with de novo immune hepatitis after liver transplantation. These antibodies have also been found very early in allo-HCT associated with acute hepatic GvHD but in all the cases the donor cells had experienced previous priming through pregnancies. It remained to be explored whether or not primary recognition of the antigen occurs after HCT and what could be the consequences in the long term outcome. We genotyped a cohort of 68 HCT patients and found 11 with the GSTT1 null donor/positive recipient mismatch. After testing 114 serum samples, we found a unique case of a 33-year-old patient transplanted from his HLA-identical sibling donor in which IgG GSTT1 antibodies were detected for the first time on day + 178. After stimulation of peripheral blood mononuclear cells with GSTT1 peptides we could demonstrate that this patient also had GSTT1-specific T lymphocytes that became activated upon exposure to the GSTT1 antigen. In this report, we describe the first case in which simultaneous T and B cell response against GSTT1 is developed in HCT although the clinical consequences in GvHD are still unclear.

The CTLA-4 checkpoint regulates the activation of T cells. Individuals with heterozygous mutations in CTLA-4 have a complex phenotype typically characterized by antibody deficiency alongside variable autoimmunity. Despite severe disease in some individuals, others remain largely unaffected with reasons for this variation unknown. We studied a large family carrying a single point mutation in CTLA-4 leading to an amino acid change R75W and compared both unaffected with affected individuals. We measured a variety of features pertaining to T cell and CTLA-4 biology and observed that at the cellular level there was complete penetrance of CTLA-4 mutations. Accordingly, unaffected individuals were indistinguishable from those with disease in terms of level of CTLA-4 expression, percentage of Treg, upregulation of CTLA-4 upon stimulation and proliferation of CD4 T cells. We conclude that the wide variation in disease phenotype is influenced by immune variation outside of CTLA-4 biology.

AIM To investigate the role of glutathione S-transferase T1 donor-specific T lymphocytes in plasma cell-rich rejection of liver allografts. METHODS The study group included 22 liver transplant patients. Among them, 18 patients were mismatched for the glutathione S-transferase T1 (GSTT1) alleles (don+/rec-), and 4 were matched (don+/rec+). Seven of the mismatched patients produced anti-GSTT1 antibodies and developed plasma cell-rich rejection (former de novo immune hepatitis). For the detection of specific T lymphocytes, peripheral blood mononuclear cells were collected and stored in liquid nitrogen. The memory T cell response was studied by adding to the cell cultures to a mix of 39 custom-made, 15-mer overlapping peptides, which covered the entire GSTT1 amino acid sequence. The specific cellular response to peptides was analyzed by flow cytometry using the markers CD8, CD4, IL-4 and IFNγ. RESULTS Activation of CD8+ T cells with different peptides was observed exclusively in the group of patients with plasma-cell rich rejection (3 out of 7), with production of IL-4 and/or IFNγ at a rate of 1%-4.92% depending on the peptides. The CD4+ response was most common and not exclusive for patients with the disease, where 5 out of 7 showed percentages of activated cells from 1.24% to 31.34%. Additionally, two patients without the disease but with the mismatch had cells that became stimulated with some peptides (1.45%-5.18%). Highly unexpected was the finding of a double positive CD4+CD8low T cell population that showed the highest degree of activation with some of the peptides in 7 patients with the mismatch, in 4 patients with plasma cell-rich rejection and in 3 patients without the disease. Unfortunately, CD4+CD8low cells represent 1% of the total number of lymphocytes, and stimulation could not be analyzed in 9 patients due to the low number of gated cells. Cells from the 4 patients included as controls did not show activation with any of the peptides. CONCLUSION Patients with GSTT1 mismatch can develop a specific T-cell response, but the potential role of this response in the pathogenesis of plasma cell-rich rejection is unknown.

Background: Quantification of T-cell-receptor-excision circles (TRECs) and kappa-deleting-recombination-excision circles (KRECs) from dried blood spots (DBS) allows detection of neonates with severe T-cell and/or B-cell lymphopenia that are potentially affected by severe combined immunodeficiency (SCID), as well as X-linked agammaglobulinemia (XLA). Methods: Determination of TRECs and KRECs using a triplex RT-PCR (TRECS-KRECS-β-actin) assay from prospectively collected DBS between February 2014 and December 2016 in three hospitals in Seville, Spain. Cut-off levels were TRECs < 6/punch, KRECs < 4/punch and b-actin > 700/punch. Internal (SCID, XLA, ataxia telangiectasia) and external controls (CDC) were included. Results: A total of 8943 DBS samples obtained from 8814 neonates were analysed. Re-punching was necessary in 124 samples (1.4%) due to insufficient β-actin values (<700 copies/punch). Preterm neonates (GA < 37 weeks) and neonates with a BW < 2500 g showed significantly lower TRECs and KRECs levels (p < 0.001). Due to repeated pathological results, ten neonates were re-sampled (0.11%), of which five neonates (0.055%) confirmed the pathological results: one case was a fatal chromosomopathy (TRECs 1/KRECs 4); two were extreme premature newborns (TRECs 0/KRECs 0 and TRECs 1/KRECs 20 copies/punch); and 2 neonates were born to mothers receiving azathioprine during pregnancy (TRECs 92/KRECs 1 and TRECs 154/KRECs 3 copies/punch). All controls were correctly identified. Conclusions: Severe T- and B-cell lymphopenias were correctly identified by the TRECS-KRECS-β-actin assay. Prematurity and low BW are associated with lower TREC and KREC levels. Extreme prematurity and maternal immune suppressive therapy can cause false positive results of TRECs and KRECs values.

Background: Autosomal dominant gain-of-function mutations in PIK3R1 encoding for the regulatory subunit (p85a, p55a, and p50a) of Class IA phosphoinositide 3-kinase (PI3K) result in the activated PI3Kd syndrome (APDS) type 2 characterized by childhood-onset combined immunodeficiency, lymphoproliferation, and immune dysregulation. To improve clinical awareness and understanding of these rare diseases, we reviewed all hitherto published cases with APDS type 1 and type 2 for their clinical and immunologic symptoms and added novel clinical, immunologic, and genetic findings of two patients with APDS type 2.Methods: Clinical, immunologic, and genetic evaluation of two new patients with APDS2 was performed followed by the systematic collection of all available previously published data of patients with APDS1 and APDS2.Results: Patients with APDS type 1 (n = 49) and type 2 (n = 15) showed an indistinguishable immunologic phenotype. Overlapping clinical features shared by APDS type 1 and type 2 were observed, but our review also revealed previously unnoticed clinical differences such as remarkably high incidence of microcephaly, poor growth/short stature in patients with APDS2. Clinical management and outcome were variable and included prophylactic antibiotics, immunosuppression, immunoglobulin substitution, and hematopoietic stem cell transplantation.Conclusions: A disease-specific registry collecting prospective and long-term follow-up data of patients with APDS, as currently set up by the European Society for Immunodeficiencies, are needed to better understand the natural history and to optimize treatment concepts and thereby improving the outcome of this heterogenous patient group.

Autosomal recessive (AR) complete Interferon-gamma Receptor1 (IFN-gamma R1) deficiency is a rare variant of Mendelian susceptibility to mycobacterial disease (MSMD). Although hematopoietic stem cell transplantation (HSCT) remains the only curative treatment, outcomes are heterogeneous; delayed engraftment and/or graft rejection being commonly observed. This case report and literature review expands the knowledge about this rare but potentially fatal pathology, providing details regarding diagnosis, antimicrobial treatment, transplant performance, and outcome that may help to guide physicians caring for patients with AR complete IFN-gamma R1 or IFN-gamma R2 deficiency. (C) 2015 Wiley Periodicals, Inc.

A cross-sectional study of 77 chronic HIV-infected children revealed higher levels of biomarkers of inflammation (ultrasensitive C-reactive protein, D-dimer and β-2-microglobulin), immune activation (HLA-DR+ CD38+ CD4+ and CD8+ T cells) and microbial translocation [lipopolysaccaride (LPS), microbial 16S rDNA and sCD14] than 32 healthy controls. Immune activation was higher in viremic children, but microbial translocation occurred independently of viraemia and T cell activation. Our results do not support a relevant role of microbial translocation in T cell activation in chronic HIV-infected children, proposing a need to develop strategies to minimize microbial translocation in the future.

Hepatitis C virus (HCV)‐RNA detection in peripheral blood mononuclear cells (PBMCs) after recovery from HCV infection, is a type of occult HCV infection although is unclear how the viral persistence in PBMCs affects HCV‐specific T‐cell responses. The aim of this study was to investigate if cellular immune responses are modified by HCV persistence in PBMCs.

Objectives: To determine human beta-defensin-2 levels in term and preterm neonates at birth and to evaluate its impact on sepsis. Design: Observational study. Setting: Single tertiary care hospital. Patients: Term neonates and preterm neonates were recruited and divided in groups according to important clinical events. Interventions: Cord blood samples were drawn from all newborns immediately after birth. Human beta-defensin-2 levels were determined using enzyme-linked immunosorbent assay technology. All neonates were followed clinically during the first 30 days of life. Measurements and Main Results: Forty-two term and 31 preterm neonates were enrolled. Human beta-defensin-2 levels in term neonates were higher compared with preterm infants (median, 1,882 vs 918 pg/mL; p = 0.003) and correlated with gestational age and birth weight. Of 31 preterm neonates, seven suffered from late-onset sepsis, and this was associated with lower human beta-defensin-2 levels (median, 513 vs 1,411 pg/mL; p = 0.006). Conclusion: Preterm neonates show lower human beta-defensin-2 levels in cord blood compared with term neonates. Low human beta-defensin-2 levels in preterm neonates might be associated with an increased risk of late-onset sepsis.

CD81, the scavenger receptor-BI (SR-BI) and the low-density lipoprotein receptor (LDLR) are involved in peripheral blood mononuclear cells (PBMCs) hepatitis C virus (HCV) entry. To investigate if these molecules are altered by HCV, 20 controls and 66 patients: 37 untreated and 29 sustained virological responders, were studied. CD81 and LDLR expression, measured the percentage of cells expressing the HCV-receptors and their mean fluorescence intensity (MFI), was analyzed on lymphocytes and monocytes, as well as SR-BI on monocytes by flow cytometry. RNA was extracted from PBMCs and detection of the HCV-RNA positive and negative strands was performed by strand-specific RT-PCR. A statistically significant increase of CD81 expression was observed on lymphocytes, a higher percentage of LDLR on lymphocytes and monocytes, as well as SR-BI on monocytes was found in the patients as compared to the controls (P < 0.05 in all cases). Untreated patients showed a higher percentage of LDLR(+) lymphocytes than sustained virological responders (P = 0.025). Nineteen sustained virological responders bore the HCV-RNA positive strand in PBMCs; nine of them the negative strand too. Sustained virological responders with occult infection and viral replication, showed a higher expression of LDLR on lymphocytes (P < 0.05) and a higher LDLR MFI on monocytes (P = 0.011) than those without viral replication. In conclusion, HCV exposure modifies expression levels of the receptors studied, being LDLR related with HCV replication, not only in the classic but also in the occult infection.

Background. It has been suggested that preemptive therapy against cytomegalovirus (CMV) infection after transplantation promotes a CMV-specific immune response. Our objective was to determine whether solid-organ transplant patients at high risk for CM Vinfection treated preemptively acquire a CMV-specific immune response and whether the acquired immune response confers immunity by controlling subsequent CMV replication episodes and by protecting from late-onset CMV disease.Methods. Patients were followed up for 18 months after transplantation. CMV viral load was determined using real-time polymerase chain reaction assays, and the T-cell immune response was characterized by intracellular cytokine staining.Results. The 21 patients studied developed CMV replication episodes at a median of 4 weeks (range 2-8 weeks) after transplantation and a CMV-specific T-cell response within a median of 12 weeks (range 10-20 weeks). The decline in the incidence of CMV replication episodes is inversely correlated with the acquisition of the CMV-specific T-cell response (linear regression r(2)=0.781, Pearson correlation =-0.883; P=0.001). There were no CMV replication episodes after week 47 of transplantation. In addition, after acquisition of the immune response, 42 replication episodes were cleared without treatment. The time taken for immune clearance of replication correlated with the peak viral load (P=0.01). No incidence of CMV early or late-onset disease was detected.Conclusions. Our results demonstrate that preemptive therapy is a safe and an effective strategy for the control of CMV infection in solid-organ transplant recipients at high risk for CMV infection. This is the first study that reports a therapeutic effect of the acquisition of CMV-specific immune response during preemptive treatment.