Impact of splenectomy on circulating microparticles in patients with sickle cell anemia.

INTRODUCTION: Circulating 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. METHODS: Using 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. RESULTS: Patients 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. CONCLUSION: Collectively, these results suggest that splenectomy affects circulating levels of MP regardless of the known SCA modifiers and correlates.

Mortality and complications in Omani patients with beta-thalassemia major: a long-term follow-up study.

BACKGROUND AND AIM: Beta thalassemia major (ß-TM) is a genetic blood disorder requiring lifelong blood transfusions.  The resulting iron overload damages multiple organs, particularly the heart and endocrine organs. This study aimed to describe and assess the predictors of survival and complications in Omani patients with ß-TM.   Methods: All ß-TM patients registered in the day care of Sultan Qaboos University Hospital were included in this retrospective study.   Results: There were 187 patients with ß-TM with a median follow-up of 24.9 years.  The median ages at diagnosis and the start of chelation were 0.7 and 4.8 years, respectively. The following complications developed at different time points [Median (age in years), Complication Free Probability at 20 years]: Death (20.0 years;85%), hypogonadism (15.9 years;50%), insulin-dependent or non-insulin dependent diabetes (20.0 years;88%), cardiac complications (20.3 years;91%), osteoporosis (20.7 years;96%), hypothyroidism (25.7 years;97%), liver complications (7.3 years;54%). The number of complications predicted death (P = 0.0038). Those born after 1980 had a lower risk of death (P = 0.005), hypogonadism (P = < 0.0001), and cardiac complications (P = 0.004). Higher serum ferritin at the start of chelation was associated with the development of diabetes (P = < 0. 001).   Conclusions: This long-term study shows complications development at different ages, and the number of complications is associated with survival. Later birth cohorts had a lower risk of death, hypogonadism, and cardiac complications. There was a persistent negative impact of delay in the start of iron chelation that is present even after a long follow-up. (www.actabiomedica.it).

Warfarin pharmacogenetics: polymorphisms of the CYP2C9, CYP4F2, and VKORC1 loci in a genetically admixed Omani population.

This is the first study to evaluate the spectrum and prevalence of dose-predictive genetic polymorphisms of the CYP2C9, CYP4F2 and VKORC1 loci together, in a geographically defined, ethnically admixed healthy adult Omani population sharing common lifestyle/environmental factors. Since the present-day Omani population is the result of an admixture of Caucasian, African and Asian ancestries, we compared the pharmacogenetic profile of these three loci in this population. Interestingly, the Omani pharmacogenetic profile, in terms of allele and genotype distribution, has values that are intermediate between Caucasians and African Americans, the African admixture further substantiated by the presence of the CYP2C9*8 allele. However, limitations and usefulness of such comparisons warrant caution, as the data from pharmacogenetic literature do not always represent bona fide population categories. Furthermore, definition of study population based on microgeographical scale would be more appropriate in pharmacogenetic research rather than the flawed racial, ethnic, or social categorizations since pharmacogenetic variation is clinal, and genetic influences will be further altered by lifestyle and environmental factors.

Coexistence of sickle cell disease and systemic lupus erythematosus is associated with quantitative and qualitative impairments in circulating regulatory B cells.

The incidence of connective tissue diseases such as systemic lupus erythematous (SLE), in adult patients with sickle cell disease (SCD), appears to be increasing. The exact causes underlying this increased risk are still unknown, but a link with B regulatory (Breg) cells is possible as these cells suppress inflammatory responses, and maintain tolerance. Quantitative and qualitative analyses of circulating Breg cells were performed in a cohort of SCD patients with SLE, and their levels were correlated with key soluble mediators promoting autoreactive B cells. We demonstrated that levels of Breg cells were significantly decreased in SCD patients with SLE compared to patients with SCD only or healthy controls. Functional analysis of Breg cells from SCD patients with SLE revealed impairments in IL-10 production that correlated with lower levels of STAT3 phosphorylation, without abnormal expression of IL-10 receptor on Breg cells. On the other hand, BAFF levels were substantially elevated in SCD patients with SLE, but not significantly associated with Breg cell levels. Collectively, these results indicated numerical and functional deficits of Breg cells in SCD patients with SLE and their capacity to maintain tolerance and control inflammation is imbalanced, which leads to the development of autoimmune responses.

Iron Overload in Patients With Heavily Transfused Sickle Cell Disease-Correlation of Serum Ferritin With Cardiac T2* MRI (CMRTools), Liver T2* MRI, and R2-MRI (Ferriscan®).

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.

Beta-thalassaemia major: bone marrow versus peripheral blood stem cell transplantation.

OBJECTIVE: To compare PBSCT with BMT in Thalassaemia patients in terms of rejection, non-rejection mortality, disease free survival and overall survival. METHODS: Fifty six patients were transplanted from September 2000 - July 2005. Twenty nine underwent BMT and 27 received PBSCT. Most patients were intensely transfused to keep minimum haemoglobin of 12 gm/dl and received desferioxamine, 24 hours infusion, before transplantation. Pesaro class I (n-20) and class II (n-20) received conditioning with standard Bu/Cy. Of class III (n-16), ALG was added to standard Bu/Cy in 9 who received PBSCT and 7, who received BM, were conditioned with Hydrea 20-30 mg / kg (day - 45 to -11), Azathioprin 2-3 mg / kg (day - 45 to day -11), Fludarabine 25 mg / kg (day -17 to -13) followed by Bu14 / Cy 200 started on day - 10. Triple immunosuppression was used for whole PBSC group and class III-BM group. For others, a GvHD prophylaxis comprised of MTX and cyclosporine only. MNC dose infused was > 4 x 10(8)/kg (range 4.8-8.2) recipient weight in PBSC patients and for BM its range was 1.6 - 5.2 MNC / kg. All patients received G-CSF 5mg / kg / day, from day + 5, till ANC > 0.5 x 109 / I. Median age of the donor was 8.6 years. All recipients and donors were genotypically HLA matched except in one. PBSC were harvested on day 5 of G-CSF administration. Follow up ranged from 273 - 2088 days. RESULTS: Median age for BM and PBSC group was 5.2 and 6.9 years. Engraftment was achieved in all cases. Median time to ANC of 0.5 x 10(9)/ I in BMT / PBSCT patients was 13 / 10 days (range 11-19 / 9 - 15) and for platelets of 20 x 10(9) / I it was 17 / 14 days (range 14 - 28 / 12 - 19). aGvHD (grade II - IV) was seen in 30% / 26% cases in BMT / PBSCT group. Incidence and severity of chronic GvHD was not statistically different in two groups (BM-24% & PBSC -30%). Six patients rejected the graft. Of the four who rejected the graft from class III, 3 were from PBSC group. DFS in risk classes of the two groups was not significant. Overall survival / disease free survival for the BM and PBSC group as on December 2005 was 73% / 65% and 67% / 55%. CONCLUSION: This study shows that major outcomes with PBSCT are not statistically different from BMT. Rejection and disease free survival in class 3 patients who received intensified immuno-suppression and large doses of PBSC is comparable to BM group who were conditioned according to newer Lucrali protocol.

Levels of regulatory T cells and invariant natural killer cells and their associations with regulatory B cells in patients with non-Hodgkin lymphoma.

Due to their immunoregulatory properties, several specialized cell subsets, including regulatory T (Treg), invariant natural killer T (iNKT) and regulatory B (Breg) cells, are involved in the pathogenesis of non-Hodgkin lymphoma (NHL). However, the interaction between various cells remains to be elucidated. The aim of the present study was to evaluate the levels of Treg, iNKT and Breg cell subsets and their interrelationships in the peripheral blood (PB) and bone marrow (BM) of patients with B-cell NHL who received rituximab-based regimens and achieved a complete remission. A total of 20 patients and 20 healthy age- and sex-matched controls were prospectively enrolled for investigation of Treg, iNKT and Breg cell subsets in PB and BM by flow cytometry and cell culture. Prior to administration of combination chemotherapy with rituximab, the patients had lower levels of Breg cells and, to a lesser degree, Treg cells, but not iNKT cells, in PB compared with controls. Compartmental differences in the levels of Treg and Breg cell subsets, but not iNKT cells, were observed between PB and BM, suggesting an increase in trafficking through the blood of these regulatory cell subsets to the marrow. Following complete remission, the levels of circulating Treg, iNKT and Breg cell subsets increased. The levels of Treg cells were not significantly associated with iNKT and Breg cell subsets, although negative correlations were observed. Taken together, these results may provide new insights into the potential role of regulatory cell subsets in patients with B-cell NHL. However, whether the observed differences between PB and BM may affect clinical outcomes requires further investigation.

Side effects of Deferasirox Iron Chelation in Patients with Beta Thalassemia Major or Intermedia.

OBJECTIVES: Chelating agents remain the mainstay in reducing the iron burden and extending patient survival in homozygous beta-thalassemia but adverse and toxic effects may increase with the institution and long term use of this essential therapy. This study aimed to estimate the incidence of deferasirox (DFX) side effects in patients with thalassemia major or intermedia. METHODS: A retrospective study of 72 patients (mean age: 20.3±0.9 yrs; 36 male, 36 female) with thalassemia major or intermedia treated at Sultan Qaboos University Hospital, Oman, was performed to assess the incidence of side effects related to deferasirox over a mean of 16.7 month follow-up period. RESULTS: Six patients experienced rashes and 6 had gastro-intestinal upset. DFX was discontinued in 18 patients for the following reasons: persistent progressive rise(s) in serum creatinine (7 patients; 40% mean serum creatinine rise from baseline), feeling unwell (2), severe diarrhea (1), pregnancy (1), death unrelated to chelator (2) and rise in serum transaminases (2). Three patients were reverted to desferoxamine and deferiprone combination therapy as DFX was no longer biochemically effective after 18 months of therapy. There was no correlation between baseline serum ferritin and serum creatinine or a rise in serum creatinine. Cardiac MRI T2* did not change with DFX therapy. However, there was an improvement in liver MRI T2* (p=0.013). CONCLUSION: Renal side effects related to deferasirox appear to be higher than those reported in published clinical trials. Further larger studies are required to confirm these findings.

Efficacy of hydroxyurea (HU) in reduction of pack red cell (PRC) transfusion requirement among children having beta-thalassemia major: Karachi HU trial (KHUT).

BACKGROUND: Packed red blood cell (PRC) transfusion with iron chelation is the mainstay of treatment for patients with beta-thalassemia major. Hemoglobin F augmentation is another approach to treat this hemoglobinopathy. This study evaluates the efficacy and safety of hydroxyurea (HU) in minimizing PRC transfusions in patients with beta-thalassemia major. METHOD: Twenty-three patients with beta-thalassemia major received HU at a mean dose of 16 mg/kg/d. The results were analyzed at the end of 24 months. Transfusion requirement during the 6 months preceding the study was considered as the control. RESULT: Twenty patients were evaluable after 24 months. The mean volume of PRC transfused was reduced from 2126.45 mL to 1489.59 mL (P<0.001). The interval between transfusions was increased by 68.7%. Grade I myelosuppression was observed in 4 patients and diarrhea in 2 patients. CONCLUSIONS: HU was found to be safe in patients with beta-thalassemia major, and resulted in reduction in the transfusion requirements and in increase of the intervals between transfusions.