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Background: The HLA complex involved is a factor in the pathogenesis of leukemia., Objectives: The presence of class II HLA alleles DRB1 *, DQB1 *, DPA1 *, and DPB1 * was evaluated in 47 patients with acute lymphoblastic leukemia (ALL) and 48 with chronic myeloid leukemia (CML) for comparison with 48 healthy volunteers in Zulia, Venezuela, and to evaluate potential associations of HLA with leukemia., Methods: Low- and high-resolution PCR-SSP was used for class II HLA regions DRB1 *, DQB1 *, DPA1 *, and DPB1 * following the instructions of KIT Olerup SSP Genovision., Results: Alleles HLA-DRB1*14, especially DRB1*14:21, -DPA1*1:06, -DPA1*01:03,-DPA1*02:01, and the haplotypes HLA-DPA1*01:03-DPB1*04:01, DPA1*01:03-DPB1*02:01, DPA1*01:03-DPB1*99:01, -DRB1*14-DPA1*01:03, -DRB1*15-DPA1*01:03 were associated with CML (RR > 3); alleles HLA-DRB1*13, -DQB1*02, -DPA1*01:05, -DPA1*01:09 and the haplotypes HLA-DPA1*01:09-DPB1*02:01, DPA1*01:09-DPB1*04:01 were protective (RR < 1). Alleles HLA-DQB1*04, -DQB1*05, -DPA1*1:06, -DPA1*01:07, -DPA1*1:08 had a positive association with ALL. Alleles HLA-DPA1*01:09, -DPA1*02:01, -DPB1*02:01, -DPB1*03:01 and the haplotypes HLA-DPA1*01:03-DPB1*04:02, -DPA1*01:09-DPB1*02:01, -DPA1*01:09-DPB1*04:01, -DPA1*02:01-DPB1*04:02 were negatively associated., Conclusions: The other association patterns identified suggest marked differences in the pathogenesis of leukemia, which suggests possible deficiencies in antigen presentation for ALL or potential effects of molecular mimicry in CML.

Background: A possible interaction between a specific HLA type and Adenovirus has been postulated as a promoter in leukemia clonal evolution. The HLA-DRB1*14, specifically DRB1*14:21, 14:22, 14:45, 14:26, 14:33, 14:51, 14:35 subtypes was the most frequent in CML Venezuelan patients., Objectives: It is interesting to evaluate the molecular mimicry between the Adenovirus and the DRB1*14 subtypes which exhibit the same change in the amino acid position of the DR53 epitope. This mimicked segment has been identified as a LLERRRA polypeptide., Material and Method: Experimental research conducted in the IHO Venezuela, in peripheral blood samples of patients with ALL, CML and healthy controls. Mixed culture, serology, lymphocyte proliferation and cytofluorometry were performed., Results: DRB1*14 patient's lymphocytes reacted in 48 hours mixed culture against DRB1*14 promoters lymphocytes exhibiting increased CD8+T lymphocytes. CML patients show a different serological profile against Adenovirus. Only CML patients reacted to LLERRRA peptide, increasing CD8+ T cells., Conclusion: It is established that the relationship CML, HLADRB1* 14, autoreactive CD8+ T memory cell and CD8+T specific response from Adenovirus could be at the origin of the CML in Venezuelan patients.