IL-8 Alterations in HIV-1 Infected Children With Disease Progression

Abstract

Disease progression in HIV-1 infected children is faster than in adults. Less than 5% of the infected children maintain stable CD4 counts beyond 7 years of infection and are termed long-term nonprogressors (LTNPs). Delineating the host immune response in antiretroviral naïve (ART) and treated HIV-1 infected children at different disease stages will help in understanding the immunopathogenesis of the disease.A total of 79 asymptomatic, perinatally HIV-1 infected children (50 ART naïve and 29 ART treated) and 8 seronegative donors were recruited in this study. T- and B-cell activation PCR arrays were performed from the cDNA, using total RNA extracted from the peripheral blood mononuclear cells (PBMCs) of 14 HIV-1 infected children at different stages of the disease. The differentially expressed genes were identified. Quantitative RT-PCR was performed for the (interleukin-8) IL-8 gene and its transcriptional mediators, that is, SHP2, GRB2, and IL-8R (IL-8 receptor/CXCR1). Plasma levels of IL-8 were measured by flow cytometry.Gene array data revealed a higher expression of IL-8 in the ART naïve HIV-1 infected progressors and in ART nonresponders than LTNPs and ART responders, respectively. Quantitative RT-PCR analysis demonstrated a significant higher expression of IL-8 (P < 0.001), its receptor CXCR1 (P = 0.03) and the upstream signaling molecule SHP2 (P = 0.04) in the progressors versus LTNPs. Plasma levels of IL-8 were significantly higher in progressors versus LTNPs (P < 0.001), and ART nonresponders versus ART responders (P < 0.001). A significant negative correlation of plasma levels of IL-8 with CD4 counts (cells/μL) was observed in HIV-1 infected ART naïve subjects (r = -0.488; P < 0.001), while the IL-8 levels positively correlated with viral load in the ART treated children (r = 0.5494; P < 0.001). ART naïve progressors on follow up demonstrated a significant reduction in the mRNA expression (P = 0.05) and plasma levels of IL-8 (P = 0.05) post 6 months of ART initiation suggesting the beneficial role of ART therapy in reducing inflammation in infected children.Our data suggest that IL-8 may serve as a potential prognostic marker in adjunct with CD4 counts to monitor disease progression in the HIV-1 infected children and the efficacy of ART.

FIGURE 1

Visualization of log2 (fold change) of HIV-1-specific qRT-PCR array of T and B cell activation genes. F4 represents relative mRNA expression of IL-8 gene in (A), progressors (n = 3) vs long-term nonprogressors (LTNPs) (n = 5) (B), ART nonresponders (n = 3) vs ART responders (n = 3).

FIGURE 2

Relative mRNA expression of (A), IL-8 (B), CXCR1 (C), GRB2, (D), SHP2, in PBMCs of HIV infected ART naïve children at different stages of the disease, that is, long-term nonprogressors (LTNPs) (n = 12) vs progressors (n = 16). Lines indicate the median, boxes interquartile ranges, and whiskers indicate the minimum–maximum.

FIGURE 3

Plasma levels of IL-8 (pg/mL) in HIV infected children at different stages of the disease, that is, HIV infected ART naïve, long-term nonprogressors (LTNPs) (n = 24) versus progressors (n = 26) and ART responders (n = 17) versus ART nonresponders (n = 12). Lines indicate the median, boxes interquartile ranges, and whiskers indicate the minimum–maximum.

FIGURE 4

(A) Correlation of CD4 counts with plasma levels of IL-8 in ART naïve (n = 50) HIV-1 infected children. (B) correlation of viral load with plasma levels of IL-8 in ART treated (n = 29) HIV-1 infected children.

FIGURE 5

(A), Plasma levels of IL-8 (pg/ml) in progressors (n = 15) (B), relative mRNA expression in progressors (n = 8), pre- and postinitiation of ART.