Does minor histocompatibility antigen HA-1 disparity affect the occurrence of graft-versus-host disease in tunisian recipients of hematopoietic stem cells?

INTRODUCTION: Minor histocompatibility antigen HA-1 (MiHAg-HA-1) disparity between a patient and his or her human leukocyte antigen (HLA) genoidentical donor has been widely associated with an increased risk of graft-versus-host disease following allogeneic hematopoietic stem cell transplantation. OBJECTIVE: To examine the effect of HA-1 disparity on the incidence of both acute and chronic graft-versus-host disease in Tunisian recipients of hematopoietic stem cells. METHODS: A total of 60 patients and their 60 respective sibling hematopoietic stem cell donors were enrolled in this study. All patients prophylactically received cyclosporine A and/or methotrexate for graft-versus-host disease. An HA-1 genotyping assay was performed with the SSP-PCR method, and HLA-A*0201- and/or HLA-A*0206-positive samples were identified using the Luminex HLA typing method. RESULTS: The Luminex HLA typing assay showed that 54 patients were positive for either the HLA-A*0201 or HLA-A*0206 alleles. Among these cases, six pairs were mismatched for MiHAg-HA-1. Both acute and chronic graft-versus-host disease occurred in four mismatched patients (Fisher's p-values were 0.044 and 0.170, respectively). A univariate logistic regression model analysis showed that only acute graft-versus-host disease may be affected by recipient MiHAg-HA-1 disparity (p: 0.041, OR: 6.727), while chronic graft-versus-host disease correlates with both age and recipient/donor sex mismatch (p: 0.014, OR: 8.556 and p: 0.033, OR: 8.664, respectively). CONCLUSION: Our findings support previously reported data suggesting a significant association between HA-1 disparity and the risk of acute graft-versus-host disease following hematopoietic stem cell transplantation

High Throughput Analysis Reveals Changes in Gut Microbiota and Specific Fecal Metabolomic Signature in Hematopoietic Stem Cell Transplant Patients

There is mounting evidence for the emerging role of gut microbiota (GM) and its metabolites in profoundly impacting allogenic hematopoietic stem cell transplantation (allo-HSCT) and its subsequent complications, mainly infections and graft versus host-disease (GvHD). The present study was performed in order to investigate changes in GM composition and fecal metabolic signature between transplant patients (n = 15) and healthy controls (n = 18). The intestinal microbiota was characterized by NGS and gas chromatography–mass spectrometry was employed to perform untargeted analysis of fecal metabolites. We found lower relative abundances of Actinobacteria, Firmicutes, and Bacteroidetes and a higher abundance of Proteobacteria phylum after allo-HSCT. Particularly, the GvHD microbiota was characterized by a lower relative abundance of the short-chain fatty acid-producing bacteria, namely, the Feacalibacterium, Akkermansia, and Veillonella genera and the Lachnospiraceae family, and an enrichment in multidrug-resistant bacteria belonging to Escherichia, Shigella, and Bacteroides. Moreover, network analysis showed that GvHD was linked to a higher number of positive interactions of Blautia and a significant mutual-exclusion rate of Citrobacter. The fecal metabolome was dominated by lipids in the transplant group when compared with the healthy individuals (p < 0.05). Overall, 76 metabolites were significantly altered within transplant recipients, of which 24 were selected as potential biomarkers. Furthermore, the most notable altered metabolic pathways included the TCA cycle; butanoate, propanoate, and pyruvate metabolisms; steroid biosynthesis; and glycolysis/gluconeogenesis. Specific biomarkers and altered metabolic pathways were correlated to GvHD onset. Our results showed significant shifts in gut microbiota structure and fecal metabolites characterizing allo-HSCT

Differentiation of Fanconi anemia and aplastic anemia using mitomycin C test in Tunisia

International audienceFanconi anemia (FA) is a recessive chromosomal instability syndrome that is clinically characterized by multiple symptoms. Chromosome breakage hypersensitivity to alkylating agents is the gold standard test for FA diagnosis. In this study, we provide a detailed laboratory protocol for accurate assessment of FA diagnosis based on mitomycin C (MMC) test. Induced chromosomal breakage study was successful in 171 out of 205 aplastic anemia (AA) patients. According to the sensitivity of MMC at 50 ng/ml, 38 patients (22.22%) were diagnosed as affected and 132 patients (77.17%) as unaffected. Somatic mosaicism was suspected in an 11-year-old patient with a FA phenotype. Twenty-six siblings of FA patients were also evaluated and five of them (19.23%) were diagnosed as FA. From this study, a standard protocol for diagnosis of FA was developed. It is routinely used as a diagnostic test of FA in Tunisia