In SCD patients, low-dose regimen of HU is a feasible option that ensured safety and yet did not affect efficacy.

Familial hemophagocytic lymphohistiocytosis (FHLH) is a potentially fatal disorder of immune regulation. Management includes chemotherapy followed by hematopoietic stem cell transplantation (HSCT). T cell depleted (TCD)-haploidentical HSCT could be an option for those patients who do not have HLA matching family donor. The objective of this study was to report on the outcome of TCD-haploidentical HSCT in patients with FHLH who underwent transplantation at Sultan Qaboos University Hospital (SQUH). This is a retrospective report on 12 patients with FHLH who received TCD-haploidentical HSCT at SQUH between August 2010 and December 2018. Epidemiologic characteristics and details on the transplantation procedures and complications were collected from patients' electronic records. Twelve patients with FHLH received TCD-haploidentical HSCT after a myeloablative conditioning regimen composed of treosulfan/thiotepa/fludarabine/anti-thymocyte globulin and rituximab. The mean age at transplantation was 11.67 § 8 months. All patients had Perforin gene mutations, except 1 patient who had an UNC-13D mutation. Most patients received TCRab + /CD19 + depleted grafts for faster immune reconstitution. Seven patients (58.3%) have been cured with a mean follow-up duration of 3.44 years. Four patients died of multiorgan failure secondary to gram-negative sepsis. One patient had primary graft failure, and 2 patients had mild graft-versus-host disease. Two patients had Pneumocystis carinii pneumonia, 2 had adenoviremia, and 9 patients had cytomegalovirus (CMV) viremia. Among patients with CMV viremia, 2 had evidence of disease (retinitis, enteritis). All patients with CMV viremia were treated successfully with foscarnet pre-engraftment and ganciclovir postengraftment, respectively. TCD-haploidentical HSCT could be a viable option for patients with FHLH who do not have HLA matching family donors. Infectious complications are the leading cause of death in that setting. CMV viremia was the most frequently encountered infectious complication.

No abstract

In an Omani family, four different alpha thalassemic alleles, one single-gene deletional (-α(3.7) ) and three non-deletional forms (α(TSaudi) , α(Δ5nt) , and α(ΔG) ), interact in various combinations and result in two distinct hematological phenotypes, with and without HbH inclusions. After excluding the presence of potential genetic modifiers, viz associated β-thalassemic alleles or functional alpha hemoglobin stabilizing protein (AHSP) polymorphisms, we observed that only the genetic combinations involving α(TSaudi) mutation are associated with HbH inclusions (a marker of degree of α/β-chain imbalance) and high reticulocyte count (a marker of ongoing hemolysis). Overall, the α(TSaudi) mutation is associated with a more severe α-globin deficiency than the other two (α(Δ5nt) and α(ΔG) ) non-deletional α(0) thalassemic mutations. The likely molecular explanation is that the compensatory increase in the linked α1 globin gene expression is much more compromised in cases with α(TSaudi) mutation.

Hematopoietic stem cell transplantation (HSCT) is currently the only established cure for sickle cell disease (SCD). Replacement of the stem cell that has the defective beta globin allele with the normal gene decreases hemoglobin S and the risk of complications of SCD. The irst case reported was a girl with acute myeloid leukemia and SCD who received HSCT and achieved long-term SCD and leukemia-free survival. Given the favorable outcomes of HSCT with thalassemia major using myeloablative preparative regimens, this approach became widely used in the initial studies of HSCT in SCD. The current standard of care is to use a myeloablative stem cell transplantation in patients with severe disease who have human leukocyte antigen-identical sibling. HSCT improves organ function, quality of life, and overall and disease-free survival. However, this is associated with high risk of gonadal dysfunction and graft versus host disease in addition to the mortality associated with the myeloablative HSCT. Reduced-intensity HSCT has also been reported with high rates of engraftment and favorable outcomes. This has been introduced to lower the gonadal dysfunction, mortality, and graft versus host disease associated with myeloablative approaches. Other approaches include HSCT using matched unrelated donors, cord blood units, and human leukocyte antigen haploidentical donors. Unfortunately, graft rejection is a common complication with these approaches. In this chapter, we review the indications of HSCT for SCD and outcomes of diferent transplant strategies including alternative donor transplant, graft rejection, and infertility after transplantation.