Envelope specific T cell responses & cytokine profiles in chikungunya patients hospitalized with different clinical presentations.

Background & objectives: Since the 2006 massive outbreaks, chikungunya (CHIK) is a major public health concern in India. The aim of this study was to assess envelope specific immune responses in patients with chikungunya infection. Methods: This study included 46 hospitalized patients with chikungunya virus infection (encephalitis, n=22, other systemic involvement, OSI, n=12, classical, n=12) and six controls from Ahmedabad city, Gujarat, India. T cell responses and the levels of Th1, pro/anti-inflammatory cytokines against the CHIK virus envelope antigens were assessed by lymphocyte proliferation assay and by cytometric bead array in flow cytometry, respectively. Results: Lymphoproliferative response was uniform among the patients. Comparisons of cytokines revealed significantly higher levels of interleukin (IL)-4 and IL-5 in encephalitis, OSI and classical patients versus controls. The levels of tumour necrosis factor (TNF)-were higher in classical patients categories compared to the controls. Interferon (IFN)-levels were lower in encephalitis patients versus control. Interpretation & conclusions : Our findings showed recognition of T cell epitopes on the envelope region of chikungunya virus by all patient categories. Lower level of IFN-may be associated with the severity of disease in these patients.