A Systematic Meta-analysis of Immune Signatures in Patients With Acute Chikungunya Virus Infection

Abstract

Background: Individuals infected with chikungunya virus (CHIKV) normally exhibit a variety of clinical manifestations during the acute phase of infection. However, studies in different patient cohorts have revealed that disease manifestations vary in frequency.

Methods: Disease profiles between patients with acute CHIKV-infection and febrile patients without CHIKV were compared and examined to determine whether any clinical presentations were associated with the clinical outcome of CHIKV infection. Circulatory immune mediators profiles were then characterized and compared with data from 14 independent patient cohort studies. The particular immune mediator signature that defines acute CHIKV infection was determined.

Results: Our findings revealed a specific pattern of clinical presentations of joint-specific arthralgia from this CHIKV cohort. More importantly, we identified an immune mediator signature dominated by proinflammatory cytokines, which include interferon α and γ and interleukin 2, 2R, 6, 7, 12, 15, 17, and 18, across different patient cohorts of CHIKV load associated with arthralgia.

Conclusions: To our knowledge, this is the first study that associated levels of CHIKV load with arthralgia as an indicator of acute CHIKV infection. Importantly, our findings also revealed specific immune mediator signatures that can be used to better define CHIKV infection.

Keywords: acute infection; chemokines; chikungunya virus; cytokines; meta-analysis.

Figure 1.

Analysis of chikungunya fever-specific typical disease manifestation from the Sri Lankan patient cohort. Patients were classified as follows: patients with chikungunya virus (CHIKV) infection who were polymerase chain reaction (PCR) positive (positive for viral load detection) (CHIKV PCR positive), patients with CHIKV infection who were PCR negative (negative for viral load detection but positive for CHIKV virion-based or E2EP3-based enzyme-linked immunosorbent assays [ELISAs]) (CHIKV PCR negative), and febrile patients without CHIKV infection (negative both for viral load detection and with CHIKV-based, E2EP3-based ELISAs) (non-CHIKV). A, Histograms show the percentage of patients in each group with or without arthralgia in the various joints (a combination of the small joints of hands and feet, wrist joints, and knee joints). *P < .001. B, The CHIKV PCR-positive patient group was further segregated into high viral load (HVL) and low viral load (LVL) groups before being compared with the CHIKV PCR-negative and non-CHIKV groups for the presence of arthralgia at the various indicated joints. *P < .001. C, Histograms show the percentage of patients in each group with or without swelling in their various joints (small joints of hands and feet, wrist joints, and knee joints). *P < .001. D, Patients in the CHIKV PCR-positive group were further segregated into HVL and LVL groups before being compared with the CHIKV PCR-negative and non-CHIKV groups for the presence of swelling at the various indicated joints. Statistical significance was measured using the 2-sided Fisher exact test and indicated the significance of the contingency between 2 categories of patients. *P < .001.

Figure 2.

Cytokine and chemokine profiles in patients with polymerase chain reaction (PCR)-positive chikungunya virus (CHIKV) infection. A–E, Levels of immune mediators associated with viral load in these patients. Patients with PCR-positive CHIKV infection (n = 71) are classified into 2 groups: high viral load (HVL) and low viral load (LVL). Levels of cytokines and chemokines were compared using 1-tailed Mann–Whitney U test. Data represent median levels of mediators detected. Abbreviations: IFN, interferon; IL-1Ra, interleukin 1Ra; IL-8, interleukin 8; MCP-1, monocyte chemoattractant protein 1.

Figure 3.

Heat map of immune mediator profiles collected by meta-analysis [–, –33]. A total of 14 studies were initially searched and collated for the meta-analysis, together with the current Sri Lankan patient cohort. Subsequently, a single-patient study [28] was excluded and the profiles of the total number of immune mediators analyzed were represented by the heat map according to their sample types and geographic locations (in a west-to-east orientation) before being classified as proinflammatory (A) or anti-inflammatory (B) cytokines. Yellow indicates low expression; blue, high expression; gray, immune mediators not investigated in the studies. Abbreviations: IFN, interferon; IL-1α, interleukin 1α; IL-1β, interleukin 1β; IL-1Ra, interleukin 1Ra; IL-2, interleukin 2; IL-2R, interleukin 2R; IL-3, interleukin 3; IL-4, interleukin 4; IL-5, interleukin 5; IL-6, interleukin 6; IL-7, interleukin 7; IL-8, interleukin 8; IL-9, interleukin 9; IL-10, interleukin 10; IL-12, interleukin 12; IL-13, interleukin 13; IL-15, interleukin 15; IL-16, interleukin 16; IL-17, interleukin 17; IL-18, interleukin 18; IL-18P, interleukin 18P; MIF, macrophage migration inhibitory factor; TNF, tumor necrosis factor.

Figure 4.

Heat map of immune mediator profiles collected by meta-analysis [–, – 33]. The profiles of all the immune mediators analyzed in the studies included in Figure 3 were represented by the heat map according to their sample types and geographic locations (in a west-to-east orientation) before being classified as chemokines (A) or growth factors (B). Each colored well in the 4 heat maps represents the relative levels of each immune mediator. Yellow indicates low expression; blue, high expression; gray, immune mediators not investigated in the studies. Abbreviations: EGF, epidermal growth factor; G-CSF, granulocyte colony-stimulating factor; HGF, hepatocyte growth factor; IP-10, interferon gamma-induced protein 10; MCF, monocyte chemoattractant protein; MIG, monokine induced by gamma interferon; MIP, macrophage inflammatory protein.

Figure 5.

Forest plots of immune mediators that were significantly elevated in different chikungunya virus-infected patient cohorts [, , , – 32]. A, Proinflammatory cytokines. B, Anti-inflammatory cytokines. Dotted line represents no difference between mean values for healthy controls and patients with chikungunya fever; diamonds, combined effect size for each immune mediator. Abbreviations: IFN, interferon; IL-1Ra, interleukin 1Ra; IL-2, interleukin 2; IL-2R, interleukin 2R; IL-4, interleukin 4; IL-6, interleukin 6; IL-7, interleukin 7; IL-10, interleukin 10; IL-12, interleukin 12; IL-15, interleukin 15; IL-17, interleukin 17; IL-18, interleukin 18.

Figure 6.

Forest plots of immune mediators that were significantly elevated in different patient cohorts with chikungunya fever (CHIKF) [, , , –30]. A, Chemokines. B, Growth factor. Dotted line represents no differences between mean values for healthy controls and patients with chikungunya virus infection; diamonds, combined effect size for each immune mediator. Abbreviations: FGF-β, basic fibroblast growth factor; G-CSF, granulocyte colony-stimulating factor; IP-10, interferon gamma-induced protein 10; MCP-1, monocyte chemoattractant protein 1; MIG, monokine induced by gamma interferon; MIP, macrophage inflammatory protein.

Figure 7.

Signature of immune mediators in patients with acute chikungunya virus (CHIKV) infection. Immune mediators were categorized into proinflammatory cytokines (red), anti-inflammatory cytokines (blue), growth factors (green), and chemokines (yellow). Pie chart shows percentage of elevated immune mediators from each subcategory. Abbreviations: FGF-β, basic fibroblast growth factor; G-CSF, granulocyte colony-stimulating factor; IFN, interferon; IL-1Ra, interleukin 1Ra; IL-2, interleukin 2; IL-2R, interleukin 2R; IL-4, interleukin 4; IL-6, interleukin 6; IL-7, interleukin 7; IL-10, interleukin 10; IL-12, interleukin 12; IL-15, interleukin 15; IL-17, interleukin 17; IL-18, interleukin 18; IP-10, interferon gamma-induced protein 10; MCP-1, monocyte chemoattractant protein 1; MIG, monokine induced by gamma interferon; MIP, macrophage inflammatory protein.