Regulatory T cells and IL-10 as modulators of chikungunya disease outcome: a preliminary study.

Regulatory T (Treg) cells hold centre stage in regulating the immune responses in most viral infections. However, their involvement in chikungunya infection is unexplored. In the current study, the frequencies and functionality of peripheral Treg and T effector (Teff) cells were assessed during different phases of chikungunya by flow cytometry and in-vitro cytokine assays. Treg cells were also studied in rheumatoid arthritis (RA) patients, whose symptoms closely mimic chronic chikungunya arthritis patients. Frequency of Treg cells was lower in acute and chronic chikungunya arthritis patients than in recovered individuals and controls, and comparable among recovered individuals and controls. Treg/Teff ratio was lower in acute than in chronic chikungunya arthritis patients, recovered individuals and controls. Higher secretion of CHIKV specific IL-10 was observed in recovered individuals than in acute, chronic chikungunya arthritis patients and controls. Frequencies of Treg and Teff cells were higher and Treg/Teff ratio was lower in RA patients than in chronic chikungunya arthritis patients. The results indicate that reduction of Treg cells was associated with ongoing CHIKV infection and normalization of Treg cells with resolution of disease. Contrasting phenotypic data in RA and chronic chikungunya arthritis suggest an altogether different mechanism of Treg-mediated pathology in both arthritis conditions. Overall, our preliminary study, suggesting an association of peripheral Treg cells and IL-10 with recovery from chikungunya, may provide insight into chikungunya disease prognosis and warrants further study.

Post-chikungunya chronic arthritis--our experience with DMARDs over two year follow up.

AIM: 1) To study clinical features and laboratory findings in patients of post chikungunya chronic arthritis (PCCA). 2) To study effectivity of disease modifying antirheumatic drugs (DMARDs) in treatment of post-chikungunya chronic arthritis. MATERIALS AND METHODS: Sixteen Chikungunya IgM positive patients having arthritis lasting more than 3 months in spite of NSAIDs and Hydroxychloroquine therapy were selected. Their clinical, laboratory and radiological features were noted. Disease activity was assessed by clinical parameters and Disease Activity Score System (DAS 28). Functional status was assessed by HAQ Questionnaire on follow-up visits over next 2 years. Effectivity of treatment with Sulfasalazine and Methotrexate was assessed. RESULTS: Chronic inflammatory polyarthritis does occur following chikungunya infection. It involves large and small joints of hands and feet and is erosive and deforming. It is rheumatoid factor negative. AntiCCP antibody was positive in majority. Synovial biopsy revealed nongranulomatous chronic synovitis with infiltration with lymphocytes and plasma cells. It was negative for chikungunya RNA. Treatment with Sulfasalazine with and without methotrexate produced good response in 71.4 % and 12.5% respectively. CONCLUSIONS: Chronic inflammatory, erosive and rarely deforming polyarthritis does occur after acute chikungunya infection in some (5.6%). It is seronegative and AntiCCP positive in majority. DMARDs like sulfasalazine and methotrexate are required and effective in treatment of PCCA.