Impact of hydroxyurea on lymphocyte subsets in children with sickle cell anemia.

BACKGROUND: Hydroxyurea (HU) has beneficial effects in the management of sickle cell anemia (SCA), but there is a paucity of data on the effect of HU on immune cells in SCA. Herein we aimed to evaluate the effect of HU on immune profiles of Egyptian children with SCA. METHODS: This was a controlled prospective cohort study conducted in 30 children with SCA and 30 healthy age-matched controls. Flow cytometry was used to evaluate lymphocyte profiles, including CD8+ T, CD19+ B, CD3+, CD4+, natural killer (NK), NK T, T helper 1 (Th1), Th2, T cytotoxic (Tc1), and Tc2 cells, prior to and after 1 year of treatment with HU. RESULTS: HU treatment led to significant increases in hemoglobin (Hb), red blood cell, and hematocrit counts and a significant decrease in the percentage of sickle Hb, with subsequent improvement in SCA complications. Compared with baseline values, CD3+, CD4+, Th1, and CD8+ T cells were significantly increased, while NK, Th2, and Tc2 cells were significantly decreased, with a resulting increase in the Th1/Th2 and Tc1/Tc2 ratios. CONCLUSIONS: HU has the beneficial effect of restoring the abnormally elevated immune parameters in children with SCA. IMPACT: Hydroxyurea treatment restores the abnormal immune parameters in children with sickle cell anemia. HU treatment led to significantly increased CD3+, CD4+, Th1, and CD8+ T cells, while NK, Th2, and Tc2 cells were significantly decreased, with a resulting increase in the Th1/Th2 and Tc1/Tc2 ratios. Our study showed the impact of HU therapy on immune parameters in children with SCA.

Refractory Thrombocytopenia Is a Valid Early Diagnostic Criteria for Hepatic Veno-Occlusive Disease in Children.

We compared the incidence of refractory thrombocytopenia (RT) and platelet transfusion requirements (PTR) in 35 children who developed veno-occlusive disease (VOD) with 35 matched control subjects who underwent hematopoietic stem cell transplant but did not develop VOD. RT developed in 100% of the VOD patients, at a median of 8 days before VOD diagnosis, as compared with 71.5% of the control group. VOD patients required more platelet transfusions than control subjects (median PTR, 6.9 mL/kg [range, .57 to 17.59] versus 3.57 mL/kg [range, 0 to 14.63], respectively) with a statistically significant difference (P < .0001). The number of days with platelet requirements was significantly higher for VOD patients as compared with control subjects (median 68% versus 39%, P =< .0001). The PTR peaked at ~12 mL/kg/day, 2 days before VOD diagnosis, whereas the PTR in the control population was 5 mL/kg/day. The positive predictive value of developing VOD was 88.9% (95% confidence interval, 66.5% to 97%) in patients who were given >7 mL/kg/day of platelets during the at-risk period of days +3 to +13 after transplant. For patients who received >8 mL/kg/day of platelets, the positive predictive value of developing VOD was 86.7% (95% confidence interval, 61.2% to 96.4%). There was no difference in the PTR in patients with mild to moderate VOD as compared with severe VOD; however, the PTR was higher in patients whose VOD did not resolve. The median daily PTR after the diagnosis of VOD in 17 patients who got defibrotide as compared with those who did not get defibrotide was 6.04 mL/kg and 5.72 mL/kg, respectively, but the difference was not statistically significant (P = .56). On univariate and multivariate analysis use of intravenous immunoglobulin was significantly associated with VOD (P = .0088) but was not significantly associated with fatal VOD. In conclusion, RT occurs in 100% of patients at a median of 8 days before VOD diagnosis. VOD should be suspected in any patient with RT after the exclusion of other causes of consumptive thrombocytopenia, especially if they require >7 mL/kg/day of platelets.

Clinical Signs and Treatment of New-Onset Bone Marrow Failure Associated SARS-CoV-2 Infection in Children: A Single Institution Prospective Cohort Study.

Background: Viral infections can cause direct and indirect damage to hematopoietic stem cells. The objectives of this study were to identify the frequency and severity of aplastic anemia in children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as well as recognize the response to treatment. Methodology: 13 children with newly diagnosed severe aplastic anemia were enrolled in this prospective clinical trial. Blood samples were obtained from all patients to detect SARS-CoV-2 antibodies, and nasopharyngeal swabs were collected for reverse-transcription Polymerase Chain Reaction to detect SARS-CoV-2 viruses. According to the laboratory results, patients were classified as having SARS-CoV-2 positive antibodies and SARS-CoV-2 negative antibodies. Both groups received combined cyclosporine (CsA) + Eltrombopag (E-PAG). The hematological response, either complete response (CR) or partial response (PR), no response (NR), and overall response (OR) rates of combined E-PAG + CsA treatment after 6 months were evaluated. Results: Four children were recognized to have aplastic anemia and SARS-CoV-2 positive antibodies. Two patients fulfilled the hematological criteria for CR and no longer required transfusion of packed red blood cells (PRBCs) or platelets, and one had PR and was still PRBC transfusion-dependent but no longer required platelet transfusion. The remaining patient showed NR, and he had died before reaching the top of the HSCT waiting list. Moreover, six patients in the SARS-CoV-2 negative antibodies group had CR, while three patients had PR. The difference in ANC, Hg, and platelet counts between both groups was not significant. Conclusion: The SARS-CoV-2 virus is added to several viral infections known to be implicated in the pathogenesis of aplastic anemia. Studies are needed to establish a definitive association and determine whether the response of bone marrow failure to standard therapy differs from that of idiopathic cases.

Effect of Hydroxyurea Treatment on the Inflammatory Markers Among Children With Sickle Cell Disease.

BACKGROUND: Neutrophil-to-lymphocyte ratio (NLR) was introduced as a potential inflammatory marker in sickle cell disease (SCD). This study aimed to evaluate the impact of hydroxyurea (HU) treatment on the value of NLR and some inflammatory mediators in SCD. METHODS: The hematological parameters and clinical events were analyzed in 35 children with SCD under HU treatment and followed up for 1 year and in 20 healthy controls. Enzyme-linked immunosorbent assay was performed for the evaluation of proinflammatory cytokines, including interleukin (IL) 6, IL-8, high-sensitivity C-reactive protein (hs-CRP), and tumor necrosis factor α (TNF-α). RESULTS: Hydroxyurea significantly improves most of the hematological parameters in children with SCD. The percentages of hemoglobin fraction S, serum levels of TNF-α and IL-6 were significantly decreased when compared to baseline value but did not reach the value of the healthy control. The HU treatment led to a significant decrease in NLR compared to the baseline values and reached healthy control values. Neutrophil-to-lymphocyte ratio was positively correlated with hs-CRP, TNF-α, and IL-8 serum levels and negatively correlated with percentage of fetal hemoglobin and hematocrit values. The cutoff value of NLR to expect a response to HU among SCD was 3.0, with 76% specificity and 85% sensitivity (area under the curve: 0.85, P < .0001). In conclusion, hydroxyurea induced a decrease in NLR and inflammatory cytokines, which represent a biomarker of inflammation in SCD. The calculation of NLR is a straightforward and cheap method for SCD outcome prediction in young children.

Circulating Microparticles in Children With Sickle Cell Anemia in a Tertiary Center in Upper Egypt.

Sickle cell disease (SCD) is a genetically inherited hemolytic anemia increasingly appreciated as a chronic inflammatory condition and hypercoagulable state with high thrombotic risk. It is associated with disturbed immune phenotype and function and circulating microparticles (MPs) derived from multiple cell sources. This study was carried out to determine MPs profiles in patients with sickle cell anemia (either on hydroxyurea (HU) therapy or those with no disease-modifying therapy) and to compare these profiles with healthy children. Moreover, our study assesses the potential impact of HU on other aspects of circulating MPs. We performed a cross-sectional study on 30 pediatric patients with SCD divided by treatment into 2 groups (those receiving HU or no therapy) attending Hematology Clinic and 20 age-matched healthy children. The blood samples obtained were analyzed for MPs by flow cytometry. Sickle cell disease group with no therapy showed elevated levels of total, platelet, and erythroid MPs. In contrast, therapy with HU was associated with normalization of MPs. This study provided additional evidence that HU is an effective treatment option in pediatric patients with SCD, as it seems that it decreases the abnormally elevated MPs in those patients.