High frequency of human leukocyte antigen class II DRB1*1602 haplotype in Greek patients with myelodysplastic syndrome and of DRB1*1501 in the low-risk subgroup.

ABSTRACT

Myelodysplastic syndromes (MDS) comprise a heterogenous group of clonal hematopoietic disorders in which the immune-mediated pathogenetic mechanisms are under investigation. Overrepresentation of human leukocyte antigen (HLA)-DR2 and its serologic split HLA-DR15 has been associated with low-risk MDS in certain ethnic groups and has been proposed as a predictive factor for a favorable response to immunomodulatory treatment. Because the HLA-DRB1*15 haplotype does not predominate in the Greek population, we investigated the frequency of HLA-DRB1 alleles among 114 patients of Greek origin suffering from various types of MDS 36 refractory anemia (RA), 24 refractory anemia with ringed sideroblasts (RARS), 19 refractory anemia with excess of blasts (RAEB), 14 refractory anemia with excess of blasts in transformation (RAEB-t), 14 chronic myelomonocytic leukemia, and 7 hypoplastic MDS patients. HLA-DRB1 molecular typing was performed with polymerase chain reaction-sequence specific oligonucleotides and results were compared with that from a previously reported control Greek population. HLA-DRB1*1602 was the only allele that was significantly overrepresented in Greek MDS patients as a whole, whereas HLA-DRB1*1501 allele frequency was significantly higher in Greek patients with low-risk myelodysplasia. Our results suggest the possible value of HLA-DR15 and HLA-DR16 as determinants for immunomodulatory interventions, at least for Greek patients with low-risk MDS.