Experimental and clinical characteristics in myelodysplastic syndrome patients with or without HLA-DR15 allele.

We studied the effects of the presence of the HLA-DR15 allele on the experimental and clinical features of myelodysplastic syndrome (MDS) by assessing the clinical data of 136 patients with MDS. We observed that the frequency of HLA-DR15 expression in MDS patients (38.7%) was significantly higher than that in the healthy controls (p < 0.01). We noted the following observations with regard to disease progression: None of the 46 HLA-DR15 positive patients with international prognostic scoring system (IPSS) scores <or=1 developed acute myeloid leukaemia (AML) during the follow-up period, while six of the 63 DR15-negative patients with the same IPSS score developed AML within a shorter follow-up period (p = 0.039). Furthermore, the incidence of poor chromosomal abnormalities, the percentage of patients with IPSS scores >or=1.5 and the presence of >or=5% blasts in the bone marrow in the DR15-positive patients were lower than the corresponding findings in the DR15-negative patients. In addition, we also recorded the following observations with regard to bone marrow (BM) failure: The bicytopenia/pancytopenia ratio in the DR15-positive patients was higher than that in the DR15-negative patients (92.4 vs. 78.3%; p = 0.029). The peripheral-neutrophil count and the platelet count in the DR15-positive patients were lower than those in the DR15-negative patients (p = 0.028 and p = 0.011, respectively). Moreover, hypocellularity was more easily detectable in the DR15-positive patients (26.4 vs. 16.9%). In addition, the BM CD4+ lymphocyte count and the CD4/CD8 ratio in the DR15-positive patients were higher than the corresponding values in the DR15-negative patients (p < 0.05 for both). However, there were no significant differences between the polarization of T-helper (T(h)) and T-cytotoxic (T(c)) cells and the cytokine levels in these two patient groups. We concluded that the presence of the HLA-DR15 allele is indicative of a genetic susceptibility to MDS and, the presence of the HLA-DR15 allele showed less association with disease progression and greater association with BM failure.