Study of class I and II HLA alleles in 30 ecuadorian patients with rheumatoid arthritis compared with alleles from healthy and affected subjects with other rheumatic diseases.

INTRODUCTION Rheumatoid arthritis (RA) is a chronic systemic inflammatory autoimmune disease that originates from a disabling disorder. To date, the etiology of RA is unknown. However, the existence of genetically susceptible individuals was considered. Many studies have been performed worldwide, for example, in Poland, Argentina, Chile, Mexico, Brazil, and Colombia, among others, regarding the influence between HLA-DR alleles and disease, but not in Ecuador. OBJECTIVE The aim of this study was to determine the involvement of Class I and II HLA alleles in patients with RA. PATIENTS AND METHODS This study was conducted in 30 adult patients with RA previously diagnosed, according to the classification criteria of the American College of Rheumatology (ACR, 1987) and 28 controls. For Class I and II HLA typing, we adopted the PCR-SSP, and statistical significances were evaluated by Chi-Square. RESULTS HLA-DR4 is present in 76.7% of patients, with an allele frequency of 45%, while only 21% of control subjects presented it. The chi-square confirms that HLA-DR4 and RA variables are highly bound (X2 = 11.38, P = 0.00074). CONCLUSION There is increased frequency of HLA-DR4 and HLA-DR14. The results are similar to those found in other studies. But it would be desirable to increase the sample size in order to find a greater number of genetic profiles and alleles involved.