Background/Purpose:

To compare the frequency of Collagen II reactive T cells in RA patients and healthy control and evaluating the relationship of Collagen II reactive T cells with disease activity in RA patients.

Materials and Methods:

Patients with a clinical diagnosis of Rheumatoid arthritis on fulfilling 1987 ACR criteria were included in the study. Patients were compared with a group of age and gender matched healthy subjects. T cell proliferative response was assessed against Bovine Collagen II, PHA (positive control) and RPMI (negative control) by measuring incorporation of the 5-bromo-2- deoxyuridine (BrdU) into DNA of proliferating cells and expression of CD25 on proliferating cells and was subsequently detected with monoclonal antibodies (BrdU-moAb and CD25-moAb)  as percentage of CD3+/BrdU+ and CD3+/CD25+ T-cells, respectively.

RA patients were classified into three groups of mild, moderate and severe disease activity as per Simplified disease activity index for RA. Four parameters, frequency of CD3+/BrdU+ , frequency of CD3+/CD25+ T-cells, Mean Fluorescent Intensity (MFI) of BrdU-FITC and MFI of CD25-FITC were compared in mild, moderate and severe disease activity groups.

Results:

Five male and twenty five female RA patients with an age range of 28-60 years (mean 42 years) and 25-58 years (mean 36 years) respectively were studied. Percentages of CD3+/CD25+ cells and CD3+/BrdU+ cells in T lymphocytes from RA patients induced by Collagen II were much higher (45.22% and 53.45%) than those observed for T lymphocytes in control group (33.51% and 45.22% ). The difference was statistically significant (p<0.05).

Statistically significant differences were observed when frequency of CD3+/BrdU+ cells and CD3+/CD25+ cells along with MFI of BrdU-FITC and CD25-FITC was compared between the three disease activity groups, mild, moderate and severe in patients (p<0.05).

Conclusion:

These observations suggest that Collagen II is an important auto antigen in joints of RA patients with Collagen II reactive T cells playing a critical role in pathogenesis of RA and Collagen II reactive T lymphocytes may be used as a specific prognostic laboratory marker for assessment of disease activity in RA.