T cell reactivity to Collagen II as a possible prognostic marker in patients with rheumatoid arthritis.

OBJECTIVE: To compare the frequency and the functional state of the collagen II reactive T cells with disease activity in rheumatoid arthritis patients and healthy controls.

METHODS: This case-control cross-sectional study was carried out at the Department of Immunology; Armed Forces Institute of Pathology, Rawalpindi, Pakistan, from June to October 2014. Rheumatologist from Rehmat Noor Rheumatology Clinic, a private health facility of the city, was requested to send in patients with clinical diagnosis of rheumatoid arthritis. Samples were obtained and relevant investigations were carried out. Data were compared with a group of age and gender-matched healthy subjects. T cell proliferative response was assessed against bovine collagen II by measuring incorporation of bromodeoxyuridine into deoxyribonucleic acid of proliferating cells and by expression of CD25 on proliferating cells as percentage of CD3+/bromodeoxyuridine+ and CD3+/CD25+ T-cells, respectively. Among the patients, the frequency of T cells with disease activity was compared. Patients were classified into groups of mild, moderate and severe disease and frequency of CD3+/bromodeoxyuridine+, frequency of CD3+/CD25+ cells, mean fluorescent intensity of bromodeoxyuridine-fluorescein isothiocyanate and mean fluorescent intensity of CD25-fluorescein isothiocyanate were compared in the groups.

RESULTS: Of the 60 subjects, 30(50%)were patients and 30(50%) were controls. Of the patients, 5(16.66%) were males and 25(83.33%) were females with an overall mean age of 42±12 years. The mean age of the controls was 41±9.28 years. Mean disease duration of the patients was 10.5 ± 4.2 years. Percentage of CD3+/CD25+ cells and CD3+/bromodeoxyuridine+ cells stimulated with collagen II, in patients was much higher than the controls(p<0.05).Statistically significant differences were observed when frequency of CD3+/bromodeoxyuridine+ cells and CD3+/CD25+ cells was compared among the mild, moderate and severe patient groups (p<0.05).

CONCLUSIONS: Collagen II was found to be an important auto antigen in joints of rheumatoid arthritis patients.