Plasma interleukin-7 correlation with human immunodeficiency virus RNA and CD4+ T cell counts, and interleukin-5 with circulating hepatitis B virus DNA may have implications in viral control

Abstract

Chronic viral infections represent a leading cause of global morbidity and mortality. Chronic HBV, HCV, and HIV infections result in cytokine perturbations that may hold key implications in understanding the complex disease mechanisms driving virus persistence and/or resolution. Here, we determined the levels of various plasma cytokines using a commercial Bio-Plex Luminex cytokine array in chronic HBV (n = 30), HCV (n = 15), and HIV (n = 40) infections and correlated with corresponding plasma viral loads (PVLs) and liver parameters. We observed differential perturbations in cytokine profiles among the study groups. The cytokines levels positively correlated with PVL and liver transaminases. The monocyte-derived cytokines viz., MIP-1β, IL-8, and TNF-α, and Th2 cytokines like IL-4, IL-5, and IL-13 showed a better correlation with liver enzymes as compared to their corresponding PVLs. Our investigation also identified two cytokines viz., IL-5 and IL-7 that inversely correlated with HBV DNA and HIV PVLs, respectively. Regression analysis adjusted for age showed that every increase of IL-5 by one unit was associated with a reduction in HBV PVL by log₁₀ 0.4, whereas, every elevation by a unit of IL-7 was associated with decreased HIV PVL by log₁₀ 2.5. We also found that IL-7 levels correlated positively with absolute CD4+ T cell counts in HIV-infected patients. We concluded that plasma IL-5 and IL-7 may likely have a key role on viral control in HBV and HIV infections, respectively. A noteworthy increase in cytokines appears to bear protective and pathological significance, and indeed is reflective of the host's versatile immune armory against viral persistence.

Keywords: HIV; chronic viral hepatitis B; cytokines; hepatitis C; liver enzymes; viral load.

FIGURE 1

Graphical outline of the study. Peripheral blood was collected from patients with HBV (N = 30), HCV (N = 15), and HIV (N = 40) and were subjected to CD4+ T cell counts and HIV, HBV, and HCV viral load estimations. Anti-HBc IgG, anti-HDV IgM, anti-HCV, and anti-HIV-1/2 antibodies were screened by ELISA. Liver function test was performed to estimate the levels of SGPT, SGOT, GGT, and ALP in plasma. Plasma cytokine levels were determined by a commercial Bio-plex cytokine array. HBV, hepatitis B virus; HCV, hepatitis C virus; HDV, hepatitis delta virus; HIV, human immunodeficiency virus; HC, healthy control; SGOT, serum glutamic oxaloacetic transaminase; SGPT, serum glutamic-pyruvic transaminase; GGT, gamma-glutamyl transferase; ALP, alkaline phosphatase.

FIGURE 2

Comparison of the levels of cytokines among patients chronically infected with hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). (A) Innate cytokines (B) Monocyte-derived cytokines, and (C) T cell-derived cytokines. The cytokines were compared across the three patient groups by the Kruskal–Wallis test. Post-hoc Mann–Whitney U tests were subsequently performed only for those biomarkers with a Kruskal–Wallis test p-value of <0.05. p-values <0.05 are considered significant; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. G-CSF, granulocyte-colony stimulating factor; GM-CSF, granulocyte-macrophage colony-stimulating factor; IFN-γ, interferon gamma; MCP-1, monocyte chemoattractant protein-1; MIP-1β, macrophage inflammatory protein-1 beta; TNF-α, tumor necrosis factor alpha; IL, interleukin.

FIGURE 3

Cytokine profiling in chronic hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) infections. (A–B) Cytokines with a > 2-fold change in patients chronically infected with HBV, HCV and HIV normalized against HCs. (C) Bar plot showing mean 2-fold change among all cytokines ranked in descending order. (D) Venn diagram depicting cytokines that are upregulated >2-fold. The Venn diagram identified 8 cytokines that are common among patients chronically infected with HBV, HCV and HIV.

FIGURE 4

Correlation between plasma viral loads, levels of liver transaminases, and cytokines. (A) Comparison between plasma viral loads (PVL) and liver enzymes among patients chronically infected with HBV, HCV, and HIV. The cytokines were compared across the three patient groups by a Kruskal–Wallis test. Post-hoc Mann–Whitney U tests were subsequently performed for those biomarkers with a Kruskal–Wallis test p-value of <0.05. (B) Spearman correlation of viral load and liver enzymes and the 17 cytokines. The R-value of each comparison was reflected by the color scale of the heatmap. (C) Spearman correlation of the two cytokines that had an inverse correlation with PVL. The exact R- and P-values were calculated. (D) Association between the levels of cytokines with PVL. P-values < 0.05 are considered significant in all tests; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. HBV, hepatitis B virus; HCV, hepatitis C virus; HIV, human immunodeficiency virus; HC, healthy control; SGOT, serum glutamic oxaloacetic transaminase; SGPT, serum glutamic-pyruvic transaminase; GGT, gamma-glutamyl transferase; ALP, alkaline phosphatase; VL, viral load.

FIGURE 5

Correlation between HIV plasma viral loads, and cytokines. Spearman correlation (A) HIV PVL and (B) IFN-γ that had an inverse correlation and (C) IL-7 that had a positive correlation with CD4+ T cell counts. The exact R- and P-values were calculated. (D) Association between age, HIV viral load (log), IL-7, and IFN-γ with CD4+ T cell counts. P-values < 0.05 are considered significant in all tests; *p < 0.05, **p < 0.01. HAART, highly active anti-retroviral therapy; HIV, human immunodeficiency virus; VL, viral load, ^†, having a trend of significance.