Frequencies of HLA-DRB1 in Iranian normal population and in patients with acute lymphoblastic leukemia.

Background: Recognition of HLA alleles is useful in transplantation and in anthropological and disease studies. Acute lymphoblastic leukemia (ALL) is the most common blood cancer. It is now generally agreed that both genetic and environmental factors play an interactive role in the development of ALL disease. It is unknown whether there exists a restriction to certain MHC genotypes in leukemia like ALL.

Methods: Genetic construct of HLA DRB1 was studied in Iranian normal populations and in patients with acute lymphoblastic leukemia using PCR-SSP method.

Results: It was shown that the most common allele in DRB1 locus in normal population was DRB1*11 (20%), whereas DRB1*09 was the least frequent allele (0.9%). Additionally, this study presented the results of HLA-DRB1 typing in 106 ALL patients and compared them with normal individuals. Comparison of the results between the normal population and the patient group revealed that there was allelic association between the DRB1*13 and the disease. Results showed that the difference between the frequencies of DRB1*13 in patients and normal individuals was significant (p=0.04), but there was a moderate difference among the frequencies of DRB1*04, *07, and *09 in childhood (0-15 years) ALL. The frequencies of DRB1*13, *04, and *07 in patients were 2.5, 16, 4.5% and, in normal individuals, were 11.4, 10, and 8.3%, respectively.

Conclusions: It should be concluded that DRB1*13, which showed a decrease in patients, should be protective against acute lymphoblastic leukemia (ALL), whereas DRB1*04, which was moderately increased in patients, could be considered a susceptible allele for childhood ALL.