ABSTRACT
To determine whether the presence of certain Human Leukocyte Antigen [HLA]-DRB1 locus is associated with production of anti-cyclic citrullinated peptide antibodies [anti-CCPAbs] and to analyze to what extent they are associated with increased susceptibility to and severity of rheumatoid arthritis [RA] in Egyptian population. Twenty nine RA patients were included in a case control study, all gave informed consents and the study was approved by the Ain Shams university ethical committee. Assessment of RA disease activity and severity was done by simplified disease activity index [SDAI] and Larsen scores respectively. Another fifteen age and sex matched subjects were also included as a control group, concentrations of anti-ccPAbs were determined in the sera of all subjects and in the synovial fluid of RA patients. The presence of HLA-DRB1 shared epitope [SE+] alleles were also determined. The alleles most strongly associated with RA susceptibility were HLA-DRB1 [01 and 04] [41.4%]. RA patients with serum anti-ccPAb titres above 60 U/ml had a higher frequency distribution of HLA-DRB1 01 [58.3%] and DRB1 04 alleles [83.3%]. There was significant positive correlation between serum and synovial anti-CCPAb titres, also between serum anti-CCPAb titres and RA disease activity and severity. HLA-DRB 1 SE+alleles [01 and 04] were strongly expressed among Egyptian RA patients. They were associated with the production of anti-CCPAb in high titres which could be involved in the disease process of RA. The presence of anti-CCPAb in high titres was associated with more active and aggressive disease. So, early determination of HLA-DRB 1 SE+alleles and serum anti-CCPAb titre in RA patients could facilitate the prediction of disease course and prognosis at the time of initial presentation