Interferon-gamma responses to Candida recover slowly or remain low in immunodeficient HIV patients responding to ART

J Clin Immunol. 2006 Mar;26(2):160-7. doi: 10.1007/s10875-006-9008-4. Epub 2006 Mar 28.

Abstract

Extended assessments of memory T-cell responses in HIV patients who have a satisfactory virological response to combination antiretroviral therapy (CART) have been limited by availability of longitudinal samples and of antigens to which most individuals (including HIV-negative controls) have been exposed. Studies of cytomegalovirus (CMV) show that interferon-gamma (IFN-gamma) responses never recover completely, but this may be antigen-specific. Here we present responses to Candida and CMV antigens analyzed using a statistical approach that derives overall trends from samples collected at variable time points. Results were considered in relation to putative markers of T-regulatory cells. Blood mononuclear cells collected from seventeen HIV-1 patients (nadir <100 CD4 T cells/mL) 0-8 years after initiation of CART were stimulated with Candida spp lysate, Candida enolase protein or CMV lysate and production of IFN-gamma was assessed by ELISpot assay. CD4 T-cell counts increased fivefold and stabilized within 24 months on CART, following control of plasma viremia. IFN-gamma responses to Candida antigens began low and increased slowly, generating positive slope up to 60 months on CART (Candida enolase p=0.008; Candida lysate p=0.03; mixed-model Wald test). Only two patients displayed a CMV or Candida-specific IFN-gamma response above the median for seronegative controls. Proportions of T cells expressing CD25 or CD57 did not correlate with IFN-gamma responses. Slow reconstitution of IFN-gamma responses to CMV and Candida in previously immunodeficient patients with restored CD4+ T-cell counts on CART suggests a broad and nonresolving defect in memory T-cell responses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Anti-Retroviral Agents / therapeutic use*
  • Antigens, Fungal / immunology
  • Antigens, Fungal / pharmacology
  • Antigens, Viral / immunology
  • Antigens, Viral / pharmacology
  • CD4-Positive T-Lymphocytes / immunology
  • Candida / enzymology
  • Candida / immunology*
  • Cellular Senescence / immunology
  • Cytomegalovirus / immunology
  • Cytomegalovirus Infections / immunology
  • Cytomegalovirus Infections / virology
  • HIV Infections / drug therapy
  • HIV Infections / immunology*
  • HIV-1*
  • Humans
  • Interferon-gamma / biosynthesis
  • Interferon-gamma / immunology*
  • Male
  • Middle Aged
  • Phosphopyruvate Hydratase / immunology
  • Phosphopyruvate Hydratase / metabolism
  • Phosphopyruvate Hydratase / pharmacology
  • RNA, Viral / metabolism
  • T-Lymphocytes / immunology

Substances

  • Anti-Retroviral Agents
  • Antigens, Fungal
  • Antigens, Viral
  • RNA, Viral
  • Interferon-gamma
  • Phosphopyruvate Hydratase