Persistent arthralgia induced by Chikungunya virus infection is associated with interleukin-6 and granulocyte macrophage colony-stimulating factor

Abstract

Background: Chikungunya virus (CHIKV) infection induces arthralgia. The involvement of inflammatory cytokines and chemokines has been suggested, but very little is known about their secretion profile in CHIKV-infected patients.

Methods: A case-control longitudinal study was performed that involved 30 adult patients with laboratory-confirmed Chikungunya fever. Their profiles of clinical disease, viral load, and immune mediators were investigated.

Results: When patients were segregated into high viral load and low viral load groups during the acute phase, those with high viremia had lymphopenia, lower levels of monocytes, neutrophilia, and signs of inflammation. The high viral load group was also characterized by a higher production of pro-inflammatory cytokines, such as interferon-α and interleukin (IL)-6, during the acute phase. As the disease progressed to the chronic phase, IL-17 became detectable. However, persistent arthralgia was associated with higher levels of IL-6 and granulocyte macrophage colony-stimulating factor, whereas patients who recovered fully had high levels of Eotaxin and hepatocyte growth factor.

Conclusions: The level of CHIKV viremia during the acute phase determined specific patterns of pro-inflammatory cytokines, which were associated with disease severity. At the chronic phase, levels of IL-6, and granulocyte macrophage colony-stimulating factor found to be associated with persistent arthralgia provide a possible explanation for the etiology of arthralgia that plagues numerous CHIKV-infected patients.

Figure 1.

Association of laboratory parameters with viral load. A, Patients were separated into 2 groups according to their viral load: high viral load (HVL; n = 14) and low viral load (LVL; n = 16). Comparisons of C-reactive protein (B), lymphocyte (C), monocyte (D), and neutrophil (E) levels between HVL and LVL groups. Data are presented as mean ± standard error of the mean (SEM). *P < .05; **P < .01; ***P < .001, Mann–Whitney U test, 1-tailed.

Figure 2.

Kinetic profiles of immune mediator expression over time during Chikungunya virus (CHIKV) infection. A, Acute phase, median 4 days after illness onset; B; Early convalescent phase, median 10 days after illness onset; C, Late convalescent phase, 4–6 weeks after illness onset; and D, chronic phase, 2–3 months after illness onset. Comparisons between patients with CHIKF and normal healthy control subjects were analyzed using a 1-tailed Mann–Whitney U test. Horizontal dotted lines represent median values for healthy control subjects. Samples from all 30 patients were analyzed for each time. Data are presented as mean ± standard error of the mean (SEM). (*P < .05; **P < .01; ***P < .001).

Figure 3.

Patterns of acute phase immune mediators, shown by 2-way hierarchical clustering. Each colored cell in the 3 hit maps represents the relative levels of expression of a particular cytokine in a patient. Green indicates low production, and red indicated high production. The first and second hit maps from the left represent the qualitative cytokine expression profiles of patients in the high viral load (HVL) and low viral load (LVL) groups, respectively. Different disease phases are illustrated: acute phase (median, 4 days after illness onset), early convalescent phase (median, 10 days after illness onset), late convalescent phase (4–6 weeks after illness onset), and chronic phase (2–3 months after illness onset).

Figure 4.

Expression of inflammatory mediators during acute Chikungunya virus (CHIKV) infection. Levels of IFN-α, IL-1Ra, IL-6, IL-12, IL-15, IP-10, and MCP-1 in infected patients were compared with those in healthy control subjects with use of the nonparametric, 1-tailed Mann–Whitney U test. Horizontal dotted lines represent median values for healthy control subjects. Data are presented as mean ± standard error of the mean (SEM). (*P < .05; **P < .01; ***P < .001). Different disease phases are illustrated: acute phase (median, 4 days after illness onset), early convalescent phase (median, 10 days after illness onset), late convalescent phase (4–6 weeks after illness onset), and chronic phase (2–3 months after illness onset).

Figure 5.

Cytokines implicated in chronic arthropathy. A, Levels of IL-6 and GM-CSF in patients who experienced persistent joint pain, compared with those in persons who made a full recovery at 2–3 months after Illness onset. B, Eotaxin and HGF levels were significantly lower in patients who still had persistent joint pain, compared with those who recovered completely. Horizontal dotted lines represent median values for healthy control subjects. *P < .05, Mann–Whitney U test, 1-tailed.