TH1 to TH2 Shift of Cytokines in Peripheral Blood of HIV-Infected Patients Is Detectable by Reverse Transcriptase Polymerase Chain Reaction but Not by Enzyme-Linked Immunosorbent Assay Under Nonstimulated Conditions

Abstract

Background:Dysregulation of cytokines has been implicated in the pathogenesis of HIV infection. Therefore, we determined tumor necrosis factor-a (TNF-α), interleukin-lβ (IL-1β), IL-4, IL-10, and interferon-γ (IFN-γ) mRNA and serum levels in HIV-infected patients under nonstimulated conditions. Material and Methods:Blood samples of 32 HIV-infected patients and 10 healthy HIV-negative controls were analyzed. Cytokine serum levels were quantified by enzyme-linked immunosorbent assay (ELISA). Cytokine mRNA levels were determined semiquantitatively by competitive reverse transcriptase polymerase chain reaction (RT-PCR) and expressed as ratios relative to those of β-actin. Results:Competitive RT-PCR was shown to be more sensitive than protein ELISA in analyzing cytokine production. We found a significant correlation between steady-state mRNA ratios and serum protein levels for TNF-α. Significantly higher cytokine mRNA ratios were found in those patients with IL-10 and IFN-γ levels detectable by ELISA. Steady-state mRNA ratios of TNF-α, IL-4, and IL-10 were significantly increased in patients with highly replicative HIV-infection. Furthermore, elevated IL-4:IFN-γ ratios were related to both high viral load and loss of CD4 cells. Discussion:Determination of steady-state mRNA ratios by semiquantitative RT-PCR represents a sensitive method to analyze cytokines in peripheral blood of HIVinfected patients under nonstimulated conditions. The data obtained with this technique provide further evidence for a TH1 to TH2 cytokine shift with progressive HIV disease. Address correspondence and reprint requests to Marcus Altfeld, Massachusetts General Hospital, AIDS Research Center, 149 13th Street, 5th floor, Charlestown, MA 02129-2000, U.S.A.; email: [email protected] Manuscript received August 2, 1999: accepted December 1, 1999. © 2000 Lippincott Williams & Wilkins, Inc.