CAREST--Multilingual Regional Integration for Health Promotion and Research on Sickle Cell Disease and Thalassemia.

Sickle cell disease (SCD) is a significant problem in the Caribbean, where many individuals have African and Asian forebears. However, reliable prevalence data and specific health care programs for SCD are often missing in this region. Closer collaboration between Caribbean territories initiated in 2006 to set up strategies to promote better equity in the health care system for SCD patients led to the formation of CAREST: the Caribbean Network of Researchers on Sickle Cell Disease and Thalassemia. We present the effectiveness of collaborations established by CAREST to promote SCD newborn screening programs and early childhood care, to facilitate health worker training and approaches for prevention and treatment of SCD complications, and to carry out inter-Caribbean research studies.

Antiplatelet antibodies detected by the MAIPA assay in newly diagnosed immune thrombocytopenia are associated with chronic outcome and higher risk of bleeding.

Immune thrombocytopenia (ITP) results in part from the presence of platelet antibodies, which can be demonstrated by the Monoclonal Antibody-Specific Immobilization of Platelet Antigens (MAIPA) assay. The aim of our study was to correlate the presence of antiplatelet autoantibodies and the natural history of ITP. We performed a retrospective, single-center study of 108 adults with newly diagnosed ITP who had indirect MAIPA assay performed at disease onset. Chronic ITP was defined by the presence of thrombocytopenia after 1 year. Bleeding diathesis was evaluated with a bleeding score. At baseline, patients with a positive indirect MAIPA have a greater bleeding score than patients with negative MAIPA assay [median (interquartile) = 8 (6-12) vs 2 (0-6), p = 0.002]. Patients with a positive indirect MAIPA also had a higher rate of chronic ITP (92.9 vs 68.7 %, p = 0.06). In multivariate analysis, a positive indirect MAIPA result and a platelet count at onset ≥10 × 10(9)/L remained independently associated with chronic ITP [adjusted OR (aOR) = 8.01; 95 % confidence interval (CI), 0.98-66.6; p = 0.05 and aOR = 3.09; 95 % CI, 1.18-8.10; p = 0.02, respectively]. Furthermore, when we analyzed together the results of direct (n = 41) and indirect MAIPA, the same results were observed. Thus, indirect MAIPA positivity at disease onset is associated with more severe hemorrhage and predicts a chronic course in adult ITP patients. MAIPA assay could be useful in the management of ITP patients when it is performed at diagnosis.

Sickle Cell Disease Newborn Screening-An Audit of a Twin Island State Pilot Program.

The prevalence of Sickle Cell Disease (SCD) within the Caribbean region remains second only to that of West Africa. The Newborn Screening (NBS) Program in Antigua and Barbuda remains heavily dependent on grants, therefore ultimately facing sustainability challenges. Early intervention and implementation of preventative measures post-NBS result in significant improvements in morbidity, quality of life, and survival. This audit reviewed the pilot SCD NBS Program in Antigua and Barbuda from September 2020 to December 2021. A conclusive result was received by 99% of babies eligible for screening, 84.3% of which were HbFA, whilst 9.6% and 4.6% were HbFAS and HbFAC, respectively. This was comparable to other Caribbean countries. Sickle Cell Disease was noted in 0.5% of babies screened, which translates to 1 in 222 live births. Eighty-two percent of mothers were aware of their sickle cell status, compared to 3% of fathers. The importance of instituting a quality improvement team post the initiation of a screening program and the need for a robust public education program have been demonstrated by this audit.

Transplantation for liver failure in patients with sickle cell disease: challenging but feasible.

Sickle cell disease (SCD) frequently affects the liver; if acute liver failure (ALF) develops, the only potentially effective therapeutic option is liver transplantation (LT). Only 12 patients for whom LT was performed for SCD-related ALF have been described so far. We report a retrospective series of 6 adult patients with SCD (3 men and 3 women, median age = 40.1 years) who underwent emergency LT. The indication for LT was ALF complicating cirrhosis in 5 patients (hepatitis C/iron overload-induced cirrhosis in 3 and iron overload-induced cirrhosis in 2); one patient had autoimmune hepatitis. The median follow-up was 52.7 months (0.5-123 months). The 1-, 3-, 5-, and 10-year survival rates were 83.3%, 66.7%, 44.4%, and 44.4%, respectively. One patient died of hepatocellular failure precipitated by hyperacute allograft rejection on post-LT day 10. Soon after LT, 2 patients developed seizures; in 1 case, the seizures were a complication of early calcineurin inhibitor-induced leukoencephalopathy. Four long-term survivors benefited from specific management of SCD; specifically, the hemoglobin S fraction was maintained below 30% and the total hemoglobin level was maintained between 8 and 10 g/dL. Two patients had mild vaso-occlusive crises. Three patients experienced a recurrence of hepatitis C virus (HCV) infection; 2 of these patients experienced reversible neurological complications while they were receiving antiviral treatment. Carefully selected patients with SCD may benefit from emergency LT. However, such patients seem to be particularly susceptible to neurological complications after LT. In contrast, severe SCD-related crises do not seem to recur if specific management is provided. Outcomes may be improved if the neurological complications can be minimized; for example, the administration of a calcineurin inhibitor can be delayed, and the management of HCV infection recurrence can be improved.

Clinical follow-up of hydroxyurea-treated adults with sickle cell disease.

Hydroxyurea-derived clinical and biological benefits and safety were retrospectively studied for 123 adult patients from 2 sickle cell disease referral centers during a total follow-up of 654 patient-years and total hydroxyurea exposure of 549 patient-years. Fifty-six adverse events occurred (incidence: 12%/patient-year), with leg ulcers being the most frequent. Adverse events could arise at any time and were usually reversible. No malignancy was observed. Clinical and biological benefits of our cohort were similar to those previously reported. Based on this relatively long retrospective study, the risk/benefit ratio for moderate hydroxyurea doses was satisfactory.

Newborn Screening for Sickle Cell Disease in the Caribbean: An Update of the Present Situation and of the Disease Prevalence.

The region surrounding the Caribbean Sea is predominantly composed of island nations for its Eastern part and the American continental coast on its Western part. A large proportion of the population, particularly in the Caribbean islands, traces its ancestry to Africa as a consequence of the Atlantic slave trade during the XVI-XVIII centuries. As a result, sickle cell disease has been largely introduced in the region. Some Caribbean countries and/or territories, such as Jamaica and the French territories, initiated newborn screening (NBS) programs for sickle cell disease more than 20 years ago. They have demonstrated the major beneficial impact on mortality and morbidity resulting from early childhood care. However, similar programs have not been implemented in much of the region. This paper presents an update of the existing NBS programs and the prevalence of sickle cell disease in the Caribbean. It demonstrates the impact of the Caribbean Network of Researchers on Sickle Cell Disease and Thalassemia (CAREST) on the extension of these programs. The presented data illustrate the importance of advocacy in convincing policy makers of the feasibility and benefit of NBS for sickle cell disease when coupled to early care.

Prevalence of sickle cell disease among Grenadian newborns.

Objective To establish the birth prevalence of sickle cell disease in Grenada, with a view to assess the requirement for a population-based neonatal screening programme. Methods A two-year pilot neonatal screening programme, involving the Ministry of Health of Grenada, the Sickle Cell Association of Grenada, and the diagnostic laboratory of hemoglobinopathies of the University Hospital of Guadeloupe, was implemented in 2014-2015 under the auspices of the Caribbean Network of Researchers on Sickle Cell Disease and Thalassemia. Results Analysis of 1914 samples processed identified the following abnormal phenotypes: 10 FS, 2 FSC, 183 FAS, 63 FAC. These data indicate ßs and ßc allele frequencies of 0.054 and 0.018, respectively. Conclusion Neonatal screening conducted in the framework of this Caribbean cooperation can allow rapid detection and earlier management of affected children.

Autoimmune thrombocytopenic Purpura and Helicobacter pylori infection.

BACKGROUND: The mechanisms triggering the production of platelet autoantibodies in autoimmune thrombocytopenic purpura (AITP) are poorly understood. Recently, marked improvements in platelet counts have been reported in patients with AITP and concurrent Helicobacter pylori infection after eradication of H pylori by a standard antibiotic regimen. We looked for an association between H pylori infection and AITP in adults. METHODS: Fifty-one adults of white French origin, negative for human immunodeficiency virus (mean +/- SD age, 40 +/- 19.8 years), with AITP and a platelet count of less than 50 x 10(3)/microL at onset were included. Thirty-five consecutive nonthrombocytopenic patients (mean +/- SD age, 43 +/- 22 years) of the same origin and with unknown H pylori status served as control subjects. Antibodies against H pylori were detected by means of an agglutination method in both patients and control subjects. Sex ratio, mean age, hemorrhagic manifestations, response to corticosteroid therapy, and final outcome were compared in H pylori-negative and H pylori-positive patients with AITP. To test for a possible molecular mimicry mechanism, we also used an immunoblot assay to look for specific H pylori antibodies in platelet eluates from 3 H pylori-positive patients with AITP. RESULTS: Seroprevalence of H pylori in patients with AITP (15 [29%]) was not significatively different from that in control subjects (10 [29%]). The H pylori-positive and H pylori-negative patients with AITP did not differ in main characteristics at AITP onset, response rate to corticosteroids, and final outcome. None of the 3 patients investigated had H pylori antibodies in platelet eluates. CONCLUSION: Although the role of H pylori in a subgroup of patients with AITP cannot be excluded, we found no evidence of an association between H pylori infection and AITP.

Platelet autoantibodies and lupus-associated thrombocytopenia.

To characterize the antigenic targets of anti-platelet antibodies (APA) found in systemic lupus erythematosus (SLE)-associated thrombocytopenia, 48 patients with immune thrombocytopenia and SLE were compared with 20 patients with SLE who had never been thrombocytopenic. Both cases and controls were tested for circulating APA by an indirect platelet suspension immunofluorescence assay (PSIIFT) and by indirect monoclonal antibody specific immobilization of platelet antigens (MAIPA). A direct platelet suspension immunofluorescence assay (PSIFT) was also used for antibodies bound to platelets in vivo in thrombocytopenic patients; 13 of them with high titres of platelets-bound APA were investigated by direct and indirect MAIPA and platelet eluate analysis. Circulating APA were detected by PSIIFT in 88% of cases and 55% of controls (P = 0.0066) and platelet-bound antibodies were detected by PSIFT in 90% of cases. Indirect MAIPA detected specific APA (mainly directed against GpIIbIIIa) in 36% of cases and only 5% of the controls (P = 0.0076). Nine out of the 13 fully investigated thrombocytopenic patients (69%) had a positive direct MAIPA and/or APA detected in platelet eluates. In conclusion, the production of specific anti-platelet autoantibodies, mainly directed against GpIIb/IIIa, and their binding to platelet membrane plays an important role in the pathogenesis of SLE-associated thrombocytopenia.

Rare RHCE phenotypes in black individuals of Afro-Caribbean origin: identification and transfusion safety.

The molecular backgrounds of variants encountered in Afro-Caribbean black individuals and associated with the production of clinically significant antibodies against high-incidence antigens (anti-RH18, anti-RH34) and against Rhe epitopes were determined. We showed that RH:-18 phenotypes are produced by 3 distinct RHCE alleles: ceEK carrying 48G>C (exon 1), 712A>G, 787A>G, 800T>A (exon 5); ceBI carrying 48G>C (exon 1), 712A>G (exon 5), 818C>T (exon 6), 1132C>G (exon 8); and the already known ceAR allele carrying 48G>C (exon 1), 712A>G, 733C>G, 787A>G, 800T>A (exon 5), and 916A>G (exon 6). The RH:-34 phenotype is produced by the (C)ce(s) haplotype described previously and composed of a hybrid D-CE(3-8)-D gene with 4 extra mutations next to a ce(s) allele (733C>G; exon 5) with an extra mutation in exon 7 (1006G>T). Partial Rhe with risk of immunization against lacking epitopes can be produced by the new ce(s) allele carrying an extra mutation in exon 3 (340C>T) and by the ceMO allele described previously. A population of sickle cell disease patients was screened to estimate the incidence of these rare alleles, with the conclusion that a procedure is required to detect the associated phenotypes in black donors to ensure transfusion safety for patients. We also described a new variant [ce(s)(748)] and variants carrying different altered alleles in nonimmunized patients and for whom the risk of immunization is discussed.