Objectives:Viral Hepatitis reactivation can occur in patients receiving tyrosine kinase inhibitors (TKIs), with potentially fatal complications. We aimed to assess hepatitis reactivation in patients with chronic myeloid leukemia (CML) treated with TKIs. Methods:We retrospectively reviewed the clinical and laboratory records, including antiviral therapy and hepatitis testing data, of CML patients treated with TKI at Sultan Qaboos University Hospital between 2006 and 2020. Results:The participants comprised 98 Omani CML patients who underwent TKI therapy (mean age = 41.1 years; range = 4-77 years). No cases met study criteria for viral hepatitis reactivation during TKI therapy. Imatinib was the first-line CML therapy for 87 (88.8%) patients; Imatinib was used as first line in 93 (94.9%) patients; most patients subsequently switched to other TKIs. Anti-HBc was positive at baseline in 16 (16.3%) patients of whom six with hepatitis B surface antigen-positivity were treated with antivirals along with TKIs, with positive outcomes. The only hepatitis C virus positive CML patient in the cohort also achieved long-term remission from both with combined interferon therapy and TKI. The overall mortality rate was nine (9.2%). Conclusions:In this cohort of Omani patients, no hepatitis B virus or hepatitis C virus reactivation case was documented in association with TKI therapy.

X-linked sideroblastic anemia (XLSA) (MIM 300752) is the most common genetic form of sideroblastic anemia, a heterogeneous group of disorders characterized by iron deposits in the mitochondria of erythroid precursors. It is due to mutations of the erythroid-specific enzyme ALAS2, the first enzyme of the heme biosynthetic pathway. Herein, we report a novel 11-bp deletion in exon 11 leading to a frameshift in the C-terminal region of the ALAS2 gene with a non-functional longer polypeptide of 614 amino acids leading to a loss-of-function mutation manifested as an X-linked sideroblastic anemia phenotype. The proband was a 29-year-old man with moderately severe microcytic hypochromic anemia with splenomegaly and increased ring sideroblasts in the bone marrow with considerable iron overload. Sanger sequencing documented a missense mutation leading to a frameshift with an elongated polypeptide of 614 AA instead of the normal 587 AA protein c.1743_1753 del (p.Gln581Hisfs*35). This mutation affected the interaction with cofactor pyridoxal 5 '-phosphate since the patient's hemoglobin improved with oral administration of pyridoxine tablets. His iron overload also responded to sustained oral iron chelation therapy with deferasirox. The screening of the entire family's kindred revealed that two other male siblings were also hemizygous for the same mutation with hypochromic microcytic anemia and tissue iron overload, whereas, three female siblings and their mother were heterozygous for the mutant allele. They did not have anemia or iron overload.

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Non-traumatic fat embolism syndrome (FES) affecting brain, lung and hematopoietic system is a rare, but a serious complication of sickle cell disease (SCD), resulting from bone marrow necrosis. SCD-related FES is rare, with the spectrum of clinical, laboratory, radiological manifestations and patient outcome is not fully understood. After medical research & ethics committee approval, retrospectively, SCD-FES patients at our centre, were reviewed between January 2006 to December 2023. 27 patients (17 males, 10 females) with a median age of 24 years and length of hospital stay of 24 (16-38) days were enrolled. They had fever, chest/back pain, cough and crepitation in 100%, 96%, 56% and 100% respectively, with neurological manifestations in 96%. Abnormal chest X-rays and CT scans were observed in 96%, and 100% respectively. Patients had significant anemia, reticulocytopenia, and thrombocytopenia, with raised WBC (p < 0.05). There was a significant rise in LDH, ALP, Ferritin and C-reactive protein levels. All patients received antibiotics, and exchange transfusions, whereas 24%, 76% required non-invasive ventilation (NIV) and mechanical ventilation respectively, with 18.5% mortality. FES is a rapidly progressive respiratory and neurological syndrome, characterized by hypoxia, and cytopenia, with raised inflammatory markers, raised LDH and ALP, with distinctive multiple cerebral microbleeds.

Sickle cell disease (SCD) is an inherited disorder characterized by abnormal mutation leading to formation of sickle red blood cells. The initial step is the formation of polymers and precipitation of Hemoglobin within the cell. voxelotor is a novel anti-polymerization drug approved for treatment of patients with SCD, resulting in improved hemoglobin level. Recently its clinical development was suspended, as concerns were raised regarding its safety and efficacy. We have evaluated 11 patients who were stable, on voxelotor for a mean period of 191 weeks (range, 8-369). We observed that upon its withdrawal, 8 patients (73%) showed a rapid onset of vaso-occlusive crisis, within a median of 4.7 days, precipitating hemolysis, with a significant drop of Hb, raised reticulocytes, bilirubin, and lactic dehydrogenase. Also, one patient (9.1%) developed acute chest syndrome, whereas five (45.5%) patients needed blood transfusions. Our data confirms that rapid withdrawal of voxelotor could precipitate severe SCD-related crisis.

Sickle cell disease (SCD) is a major public health burden worldwide with increasing morbidity and mortality. The study evaluates the risk factors associated with mortality in SCD patients, between the years 2006 and 2020 at three hospitals in Oman. The analysis includes clinical manifestations, haematological, biochemical, and radiological parameters, use of antibiotics, and blood and exchange transfusions. Our cohort included 123 patients (82 males, 41 females), with a median age of 27 (Interquartile Range 21–35 years). SCD related complications included acute chest syndrome (ACS) in 52.8%, splenic sequestration in 21.1%, right upper quadrant syndrome in 19.5%, more than > 6 VOC/year in 17.9%, and stroke in 13.8%. At the terminal admission, patients had cough, reduced O2 saturation, crepitation and fever in 24.4%, 49.6%, 53.6% and 68.3% respectively. Abnormal chest X-ray and chest CT scan were seen in 57.7%, and 76.4% respectively. Laboratory parameters showed a significant drop in hemoglobin (Hb) and platelet counts from baseline, with a significant rise in WBC, LDH and CRP from baseline (p < 0.05, Wilcoxon Signed Ranks test). All patients received antibiotics, whereas, 95.9% and 93.5% received simple blood transfusions, and exchange transfusions respectively, and 66.6% required non-invasive ventilation. Among the causes of death, ACS is seen in 32 (26%), sepsis in 49 (40%), and miscellaneous in 42 (34%). Sudden death was seen in 32 (26%) of patients. Male gender, with low HbF, rapid drop in Hb and platelet, and increased in WBC, LDH, ferritin, and CRP, correlated significantly with mortality in this cohort.

Objective: The study aims to assess the endocrine and metabolic complications in a cohort of regularly transfused and chelated beta thalassemia major patients. Methods: This is a retrospective cross-sectional study in adults aged >13years, with beta thalassemia major who were treated at a tertiary center between January 2013 to December 2022 with regular blood transfusion and chelation therapy. Iron overload was monitored by serial serum ferritin (SF) along with cardiac and liver T2* studies by MRI. Patients also underwent a comprehensive endocrine and metabolic bone disease evaluation, including screening for delayed puberty, hypogonadism, altered glucose metabolism with diabetes mellitus, hypothyroidism, hypoparathyroidism and adrenal insufficiency. Bone mineral density was evaluated by dual energy X-ray absorptiometry (DEXA) scanning along with serial serum calcium, alkaline phosphatase and 25(OH) Vitamin D studies. Results: Out of 91 patients (41 males) who are transfusion-dependent, the median (IQR) age was 33 (9) years. Hypogonadism was the commonest endocrine deficiency seen in 47 (51.6%), followed by abnormal glucose metabolism in 43 (47.3%), low bone mineral density in 34 (37.4%), delayed puberty in 31 (34.1%), hypothyroidism in 17 (18.7%), and hypoparathyroidism in 9 (9.9%) patients. Diabetes mellitus was seen in 17 (18.7%) patients with IDDM in 10(10.9%). Although, 25 (27.5%) patients had no endocrinopathy, 66 (72.5%) had at least one endocrinopathy. Conclusion: Tissue iron overload is an inevitable eventuality due to the current standard of care of beta thalassemia major patients. Hence, early screening and robust monitoring are essential to prevent complications of iron overload leading to endocrinopathies.

Introduction: Von Willebrand Disease (VWD) is the second most common inherited bleeding disorder. There is paucity of the literature describing the prevalence and clinical characteristics of VWD in this part of the world. The aim of the current study is to detect the prevalence, describe the spectrum of the different types of VWD, their mode of presentation, bleeding phenotype and outcome in Oman. Methods: A retrospective cross-sectional study was carried out in the 2 available referral tertiary care facilities in Oman namely; Sultan Qaboos University and the Royal Hospitals. The study included all children and adults diagnosed with VWD in Oman until June 2019. The patients were subtyped as per the International Society of Thrombosis and Haemostasis (ISTH) criteria. Data was collected from the electronic hospital systems in both hospitals. Out of 700 entries of VWD in both hospitals, only 140 were true cases and 560 were tested negative but wrongly labelled. Patients or their next of ken were called and interviewed to obtain the necessary information that was not documented in the electronic system. Results: A total of 140 patients are confirmed to have VWD giving a prevalence of 1:20000. Fifty eight patients are males (41.5%), 82 patients are females (58.5%). Sixty six patients have type I (47%), 38 patients have type II (27%) and 36 patients have type III (26%). The majority of patients 90 (64%) were diagnosed before the age of 20 years and 62 of them (68%) had positive family history of the disease. The most common presentation was recurrent unexplained bruising. As expected, patients with type III tend to have a significant bleeding phenotype with a bleeding score more than 5 in adults and 3 for paediatric patients. All of them were admitted to hospital at some point electively (for surgery) or for bleeding control, however, they were not put on prophylaxis. None of the patients had serious or intra-cranial bleeding. Conclusion: Von Willebrand Disease is not uncommon in Oman with an overall prevalence of 1:20000, however, it is much less than what was originally reported in previous studies in developing countries and the WFH website. The majority of patients are type 1 and have a positive family history of the disease. The disease is more common in females. All patients with type III have abnormal bleeding score and required VW factor replacement at one point. None of the patients had a serious bleed and they are not on prophylaxis. Keywords: Von Willebrand disease, Prevalence, Oman. Disclosures Al-Khabori: AstraZeneca: Honoraria; Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; SOBI: Honoraria; NovoNardisk: Membership on an entity's Board of Directors or advisory committees; Shire (Takeda): Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees.

Background: Sickle cell disease (SCD) is a major public health issue worldwide with high morbidity and mortality. SCD SD Punjab is the third most common genotype of SCD in Oman and is associated with several serious complications. The aim of the study is to establish the clinical and laboratory features of SCD patients with SD double heterozygotes and study the impact of haemoglobin F, hydroxyurea, and other modulators on the disease severity. Methods: We analyzed the electronic medical records of 52 consecutive SCD patients who were diagnosed as double heterozygote SD Punjab between 2006 and 2022. The study was approved by the local medical research and ethics committee. The data captured included SCD-related complications and current clinical and laboratory indices. Data from other studies on other SCD genotypes were used as historical controls. Results: 52 patients (31 males, 21 females) who formed this cohort had a median age of 32 years with an interquartile range (IQR) of 21-39.8 years. 37(71.2%) had <3 VOC per year, whereas 15 (28.8%) patients had >3 vasooclusive (VOC) episodes per year. SCD-related complications included Acute Chest Syndrome (ACS) (48%), Gall stones (26.9%), Avascular necrosis (AVN) (28.8%), Stroke (13.5%) and splenic sequestration (7.7%), whereas 5 (9.6%) patients of this cohort died. Surgical and Autosplenectomy were seen in 18 (34.6%). These findings were similar to other SCD genotypes in this community.19 (57.6%) were taking Hydroxyurea (HU) amongst the 33 patients who were prescribed HU. Haematological parameters showed a median (IQR) Hb (g/dl), MCV (fl), Retic count (%), WBC count(X109/L) and Platelet count(X109/L) of 9.7 (8.5-11.3), 74.9 (68.4-79.8), 4 (3.2-5.7), 9.9 (8.1-12.6) and 309 (239-428) respectively. The haemoglobin electrophoresis showed an elevated HbF, whereas serum bilirubin and LDH were elevated amongst the biochemical parameters. The use of hydroxyurea showed no impact on VOC, ACS, AVN, Stroke or mortality. Conclusion: SD Punjab is the third most common SCD genotype in Oman and was associated with recurrent VOC, ACS, AVN, and gall stones comparable to other SCD genotypes. Patients with > 3 VOC/year had significantly increased incidence of Stroke, AVN, and gallstones. However, HU was not associated with improved prognosis and better survival in this cohort of patients. Keywords: Sickle Cell Disease; Haemoglobin SD Punjab; vaso-occlusive crises; acute chest syndrome; Avascular Necrosis; HbF; hydroxyurea.

BackgroundSickle cell disease is an inherited disorder characterized by the presence of sickle hemoglobin (HbS). The process of Hb molecule polymerization is a pivotal step in the sickling process. Voxelotor, a recently approved novel therapeutic agent, is known to interfere with polymerization. We aim to study the impact of Voxelotor on Hb variants analysis using high performance liquid chromatography (HPLC).Material and methodsWe are reporting the impact of Voxelotor on Hb variants analysis using HPLC after an informed consent and medical research committee approval. Data was collected from eight patients who are enrolled in the GBT440-034OL study using electronic medical records, to evaluate the Hb levels, hemolytic markers and the clinical response.ResultsOur patients were well-balanced for gender, with a mean age of 31.1 years (19–50). Six patients showed a significant improvement in the Hb level, with reduced reticulocytes, bilirubin, LDH and an improved clinical outcome. Interestingly, these patients showed the appearance of a split band of Hb S and D on HPLC impacting significantly on HbS level. Two patients did not show any improvement on laboratory parameters, and no changes on their HPLC analysis.ConclusionsWe report here eight patients on Voxelotor therapy, six of which showed improved hemolytic markers and anemia and demonstrated the appearance of HbD peak on the HPLC chromatogram. Therefore, the absence of HbD on HPLC or other laboratory methods for estimating HbS in patients on Voxelotor therapy, gives the clinician a possible hint regarding the patient's compliance with the drug.

Relapse into the anterior ocular segment post bone marrow transplantation (BMT) for acute lymphoblastic leukemia (ALL) in a child is rare. We report this uncommon presentation as hypopyon uveitis in a patient in remission with complete chimerism after chemotherapy for ALL. The patient presented with red eye and slit lamp examination revealed hypopyon uveitis. The diagnosis of relapsed ALL was established by anterior segment aspiration followed by documentation of relapse with immunohistochemistry and flow cytometry of the fluid sample. Thus, a high index of clinical suspicion in uveitis cases post BMT, led to the early diagnosis of ocular relapse that prevented vision loss in the patient. Atypical unilateral hypopyon can therefore be an indication of relapsing ALL. Keywords: Acute Lymphoblastic Leukemia, ALL, Ocular Relapse, Hypopyon Uveitis

Aims: In a longitudinal study, we aimed to assess the correlation between ultrasound transient elastography (TE), serum ferritin (SF), liver iron content (LIC) by magnetic resonance imaging (MRI) T2* along with the fibrosis-4 (FIB-4) score as a screening tool to detect significant liver fibrosis among chronically transfusion-dependent beta-thalassemia (TDT) patients.Methods: The study was conducted at a tertiary health center treating TDT patients. Transient elastography was performed within 3 months of Liver MRI T2* examinations at the radiology department over a median of one-year duration. T-test for independent data or Mann-Whitney U test was used to analyze group differences. Spearman correlation with linear regression analysis was used to evaluate the correlation between TE liver stiffness measurements, Liver MRI T2* values, and SF levels.Results: In this study on 91 patients, the median age (IQR) of the subjects was 33 (9) years, and the median (IQR) body mass index was 23.8 (6.1) kg/m2. Median (IQR) TE by fibroscan, MRI T2*(3T), Liver iron concentration (LIC) by MRI Liver T2*, and SF levels were 6.38 (2.6) kPa, 32.4 (18) milliseconds, 7(9) g/dry wt., and 1881 (2969) ng/mL, respectively. TE measurements correlated with LIC g/dry wt. (rS =0.39, p=0.0001) and with SF level (rS =0.43, P=0.001) but not with MRI T2* values (rS =-0.24; P=0.98).Conclusion: In TDT patients, liver stiffness measured as TE decreased significantly with improved iron overload measured as LIC by MRI and SF levels. However, there was no correlation of TE with the fibrosis-4 (FIB-4) score.

Introduction: Platelet storage pool diseases (SPD) are a heterogeneous group of bleeding disorders associated with defects in the storage, secretion, or release of platelet granules. Patients with SPD present with a life-long mucocutaneous bleeding diathesis. Our goal was to study the clinical, laboratory, and ultrastructural changes in platelets of patients diagnosed with SPD using a transmission electron microscope (TEM). Methods: In this retrospective, cross-sectional cohort study, medical records of all patients referred for evaluation of a platelet function disorder were screened for an underlying diagnosis of SPD during the period 2010–2020. Results: Sixty-eight patients were identified, among whom 62 (91.2%) had a platelet function assay (PFA) study, of whom 21 (33.9%) were abnormal. Clinical, laboratory, and light transmission aggregometry (LTA) suggested that 10 (14.7%) patients had SPD; five had gray platelet syndrome (GPS), three had Hermansky Pudlak syndrome (HPS), and two had Chedia-Higashi syndrome (CHS). Most of these cases presented with mucocutaneous bleeding diathesis, but a few had oculocutaneous albinism. They were associated with variable abnormalities in the PFA and LTA studies. However, EM studies using TEM showed a reduction/absence of alpha or delta granules in GPS and HPS patients, respectively, but no abnormality in the granules of CHS patients. Conclusions: Although patients with SPD presented with bleeding diathesis, PFA and platelet aggregation studies were inconclusive. Abnormalities in platelet ultrastructure on EM studies demonstrated corroborative evidence for SPD with absent/reduced alpha or delta granules.

INTRODUCTIONCirculating microparticles (MP) are being described as potential biomarkers for disease activity in a variety of conditions including sickle cell anemia (SCA). However, relatively little is known about the influence of spleen status on MP levels in patients with SCA.METHODSUsing a prospective study design we characterize circulating MP in 144 patients with SCA in steady state by assessing their cellular origin and their relationships to spleen status defined by clinical and imaging findings. In addition, MP levels were studied according to demographic characteristics, clinical status, treatment modalities, and other hematological and biochemical parameters. Absolute plasma concentrations of MP were determined by flow cytometry.RESULTSPatients with SCA displayed a 10-fold increase in levels of MP derived from red blood cell (RBC) and platelets (PLT) when compared to their healthy counterparts (p < 0.0001). Splenectomized patients with SCA have more pronounced levels of MPRBC and MPPLT, and remained elevated after several weeks of follow-up. Levels of MP were not significantly associated with spleen removal procedures, age, gender, clinical severity score, hydroxyurea therapy, hemoglobin F, and co-existence of glucose-6-phosphate dehydrogenase deficiency.CONCLUSIONCollectively, these results suggest that splenectomy affects circulating levels of MP regardless of the known SCA modifiers and correlates.

We report herein a child with transfusion‐dependent chronic anemia, the cause of which was difficult to establish because of his transfusion dependency. The clinical and laboratory features suggested a chronic nonspherocytic hemolytic anemia (CNSHA) with bone marrow features suggestive of congenital dyserythropoietic anemia (CDA). DNA studies, however, revealed the underlying condition to be due to a novel mutation in the PKLR gene responsible for pyruvate kinase deficiency (PKD). Molecular investigations by a targeted next‐generation sequencing (t‐NGS) using a custom panel of 71 genes involved in the red blood cell (RBC) disorders revealed that the patient was homozygous for a novel missense mutation c.898G>C, p.Ala300Pro, whereas both his parents were heterozygous for the same mutation.

A 15 year child is presented with transfusion dependent chronic anemia. The clinical and laboratory features suggested a chronic nonspherocytic hemolytic anemia (CNSHA) with bone marrow suggestive of congenital dyserythropoietic anemia (CDA). DNA studies revealed the underlying novel mutation in the PKLR gene responsible for pyruvate kinase deficiency.

The treatment of sickle cell disease (SCD) is mainly supportive, except for a minority, who receive bone marrow transplantation (BMT). Serum ferritin (SF) is routinely available but is notoriously unreliable as a tool for iron-overload assessment since it is an acute-phase reactant. Although blood transfusion is one of the most effective ways to deal with specific acute and chronic complications of SCD, this strategy is often associated with alloimmunization, iron overload, and hemolytic reactions. This study, thus, aims to evaluate iron overload in patients with SCD on chronic blood transfusions and specifically, correlate SF with the current standard of care of iron-overload assessment using MRI-based imaging techniques. Amongst a historic cohort of 58 chronically transfused patients with SCD, we were able to evaluate 44 patients who are currently alive and had multiple follow-up testing. Their mean age (±SD) was 35 (9) years and comprised of 68.2% of women. The studied iron-overload parameters included cardiac T2* MRI, liver iron concentration (LIC) by Liver T2* MRI, and serial SF levels. Additionally, in a smaller cohort, we also studied LIC by FerriScan© R2-MRI. Chronic blood transfusions were necessary for severe vaso-occlusive crisis (VOC) (38.6%), severe symptomatic anemia (38.6%), past history of stroke (15.9%), and recurrent acute chest syndrome (6.9%). About 14 (24%) patients among the original cohort died following SCD-related complications. Among the patients currently receiving chelation, 26 (96%) are on Deferasirox (DFX) [Jadenu® (24) or Exjade® (2)], with good compliance and tolerance. However, one patient is still receiving IV deferoxamine (DFO), in view of the significantly high systemic iron burden. In this evaluable cohort of 44 patients, the mean SF (±SD) reduced marginally from 4,311 to 4,230 ng/ml, mean Liver T2* MRI dropped from 12 to 10.3 mg/gm dry weight, while the mean cardiac T2*MRI improved from 36.8 to 39.5 ms. There was a mild to moderate correlation between the baseline and final values of SF ng/ml, r = 0.33, p = 0.01; Cardiac T2* MRI ms, r = 0.3, p = 0.02 and Liver T2* MRI mg/kg dry weight, r = 0.6, p < 0.001. Overall, there was a positive correlation between SF and Liver T2* MRI (Pearson's r = 0.78, p < 0.001). Cardiac T2*MRI increased with the decreasing SF concentration, showing a negative correlation which was statistically significant (Pearson's r = −0.6, p < 0.001). Furthermore, there was an excellent correlation between SF ng/ml and LIC by FerriScan© R2-MRI mg/g or mmol/kg (Spearmen's rho = −0.723, p < 0.008) in a small subset of patients (n = 14) who underwent the procedure. In conclusion, our study demonstrated a good correlation between serial SF and LIC by either Liver MRI T2* or by FerriScan© R2-MRI, even though SF is an acute-phase reactant. It also confirms the cardiac sparing effect in patients with SCD, even with the significant transfusion-related iron burden. About 14 (24%) patients of the original cohort died over the past 15 years, indicative of a negative impact of iron overload on disease morbidity and mortality.

INTRODUCTION:Stem cell enumeration by the hematopoietic progenitor cells (HPC) mode is a novel method available from Sysmex XN2000 hematology analyzer. A small amount of blood (190 μL) is required, and the results are available in a few minutes without manual gating or presample treatment. The present study compares stem cell measurements using XN2000 analyzer HPC mode and FC500 flow cytometry analyzer using peripheral blood (PB) specimens and apheresis products.METHODS:In this prospective study, CD34-positive cell counts were enumerated using an FC500 flow cytometry analyzer and compared with XN2000 Sysmex analyzer (XN-HPC mode) in the same samples. Results were compared using Bland-Altman plots.RESULTS:A total of 103 samples were used. In the PB samples, the median HPC count and CD34-positive cells were 83.5 × 106 /L and 78.0 × 106 /L, respectively. The mean Bland-Altman difference was 4.5 × 106 /L (Limits: -51.7 to 60.7 × 106 /L), with a Pearson's correlation of 0.79. In the apheresis products, the median HPC count and CD34-positive cells were 1468 × 106 /L (IQR: 1049 - 1960 × 106 /L) and 1327 × 106 /L (IQR: 910 - 2001 × 106 /L), respectively. The mean Bland-Altman difference was 179.0 × 106 /L (Limits: -2022.2 - 2380.2 × 106 /L), with a Pearson's correlation of 0.58.CONCLUSION:The XN-HPC mode has an excellent correlation and minimal disagreement for stem cell enumeration in PB compared with flow cytometry and could replace it. There is high disagreement in apheresis products, and therefore, the XN-HPC mode cannot be recommended.

Vaccines against acute respiratory syndrome Coronavirus 2(SARS-CoV2) are critical weapons to control the spread of the deadly Coronavirus 2019(COVId-19) virus worldwide. Although these vaccines are generally safe, their widespread use has produced reports of rare complications, including vaccine-induced immune thrombotic thrombocytopenia (VIITT), particularly in connection with ChAdOx1 nCov-19. We have identified three cases of sickle cell disease (SCD) experiencing a severe vaso-occlusive crisis (VOC) shortly after the vaccine. Despite being stable for a long time, they had fever with tachycardia, along with a significant rise in WBC, liver enzymes, particularly alkaline phosphate, with a remarkable drop in hemoglobin, and platelets and one of them probably had fatal TTP like syndrome. Given these findings, physicians and patients should exercise caution when taking this type of vaccine and be aware of these safety concerns.

Vaccines against acute respiratory syndrome Coronavirus 2(SARS-CoV2) are critical weapons to control the spread of the deadly Coronavirus 2019(COVId-19) virus worldwide. Although these vaccines are generally safe, their widespread use has produced reports of rare complications, including vaccine-induced immune thrombotic thrombocytopenia (VIITT), particularly in connection with ChAdOx1 nCov-19. We have identified three cases of sickle cell disease (SCD) experiencing a severe vaso-occlusive crisis (VOC) shortly after the vaccine. Despite being stable for a long time, they had fever with tachycardia, along with a significant rise in WBC, liver enzymes, particularly alkaline phosphate, with a remarkable drop in hemoglobin, and platelets and one of them had probably a fatal TTP like syndrome. Given these findings, physicians and patients should exercise caution when taking this type of vaccine and be aware of these safety concerns.