Control of immunopathology during chikungunya virus infection

After several decades of epidemiologic silence, chikungunya virus (CHIKV) has recently re-emerged, causing explosive outbreaks and reaching the 5 continents. Transmitted through the bite of Aedes species mosquitoes, CHIKV is responsible for an acute febrile illness accompanied by several characteristic symptoms, including cutaneous rash, myalgia, and arthralgia, with the latter sometimes persisting for months or years. Although CHIKV has previously been known as a relatively benign disease, more recent epidemic events have brought waves of increased morbidity and fatality, leading it to become a serious public health problem. The host's immune response plays a crucial role in controlling the infection, but it might also contribute to the promotion of viral spread and immunopathology. This review focuses on the immune responses to CHIKV in human subjects with an emphasis on early antiviral immune responses. We assess recent developments in the understanding of their possible Janus-faced effects in the control of viral infection and pathogenesis. Although preventive vaccination and specific therapies are yet to be developed, exploring this interesting model of virus-host interactions might have a strong effect on the design of novel therapeutic options to minimize immunopathology without impairing beneficial host defenses.