Chikungunya virus (CHIKV)
infection causes intense
cytokine/
chemokine inflammatory responses and debilitating
joint pain. Indoleamine2,3-dioxygenase 1 (IDO-1) is an
enzyme that initiates the
tryptophan degradation that is important in initial host innate immune defense against infectious pathogens. Besides that, IDO-1 activation acts as a regulatory mechanism to prevent overactive host immune responses. In this study, we evaluated IDO-1 activity and
cytokine/
chemokine patterns in CHIKV patients. Higher IDO-1 (Kyn/Trp ratio) activation was observed during the early acute phase of CHIKV
infection and declined in the chronic phase. Importantly, increased concentrations of
Tumor Necrosis Factor-α (TNF-α),
Interleukin-6 (IL-6),
Interferon γ (IFN-γ), C-C motif
chemokine ligand 2/
Monocyte Chemoattractant Protein-1 (CCL2/MCP-1) and C-X-C motif
chemokine ligand 10/
Interferon Protein-10 (CXCL10/IP-10) were found in the acute phase of
infection, while C-C motif
chemokine ligand 4/
Macrophage Inflammatory Protein 1 β (CCL4/MIP-1β) was found at increased concentrations in the chronic phase. Likewise, CHIKV patients with
arthritis had significantly higher concentrations of CCL4/MIP-1β compared to patients without
arthritis. Taken together, these data demonstrated increased IDO-1 activity, possibly exerting both
antiviral effects and regulating exacerbated inflammatory responses. CCL4/MIP-1β may have an important role in the persistent
inflammation and arthritic symptoms following chikungunya
infection.