RESUMEN
OBJECTIVE: To determine frequencies of HLA DRß1 alleles in rheumatoid arthritis in Pakistani patients. STUDY DESIGN: Cross sectional/analytical study. PLACE AND DURATION OF STUDY: Department of Immunology, Armed Forces Institute of Pathology, Rawalpindi in collaboration with Rheumatology departments of Military Hospital, Rawalpindi and Fauji Foundation Hospital, Rawalpindi, from January 2009 to January 2010. METHODOLOGY: HLA DRß1 genotyping of one hundred Pakistani patients, diagnosed as having RA as per American College of Rheumatology revised criteria 1987, was done. HLA DRß1 genotyping was carried out at allele group level (DRß1*01-DRß1*16) by sequence specific primers in RA patients. Comparison of HLA DRß1 allele frequencies between patients and control groups was made using Pearson's chi-square test to find possible association of HLA DRß1 alleles with RA in Pakistani rheumatoid patients. RESULTS: HLA DRß1*04 was expressed with significantly increased frequency in patients with rheumatoid arthritis (p <0.05). HLA DRß1*11 was expressed statistically significantly more in control group as compared to rheumatoid patients indicating a possible protective effect. There was no statistically significant difference observed in frequencies of HLA DRß1 allele *01, DRß1 allele *03, DRß1 allele *07, DRß1 allele *08, DRß1 allele *09, DRß1 allele*10, DRß1 allele *12, DRß1 allele *13, DRß1 allele *14, DRß1 allele *15 and DRß1 allele *16 between patients and control groups. CONCLUSION: The identification of susceptible HLA DRß1 alleles in Pakistani RA patients may help physicians to make early decisions regarding initiation of early intensive therapy with disease modifying anti rheumatic medicines and biological agents decreasing disability in RA patients.