Cytokines in parvovirus B19 infection as an aid to understanding chronic fatigue syndrome.

Human parvovirus B19 infection has been associated with various clinical manifestations of a rheumatic nature such as arthritis, fatigue, and chronic fatigue syndrome (CFS), which can persist for years after the acute phase. The authors have demonstrated recently that acute B19 infection is accompanied by raised circulating levels of IL-1b, IL-6, TNF-a, and IFN-g and that raised circulating levels of TNF-a and IFN-g persist and are accompanied by MCP-1 in those patients who develop CFS. A resolution of clinical symptoms and cytokine dysregulation after intravenous immunoglobulin (IVIG) therapy, which is the only specific treatment for parvovirus B19 infection, also has been reported. Although CFS may be caused by various microbial and other triggers, that triggered by B19 virus is clinically indistinguishable from idiopathic CFS and exhibits similar cytokine abnormalities and may represent an accessible model for the study of CFS.