Interferon-gamma responses to Candida recover slowly or remain low in immunodeficient HIV patients responding to ART.
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.
School of Surgery and Pathology, University of Western Australia, Nedlands, Australia.
Kate
K
Burgess
Patricia
P
Price
Ian R
IR
James
Shelley F
SF
Stone
Niamh M
NM
Keane
Andrew Y F
AY
Lim
John R
JR
Warmington
Martyn A
MA
French
D000328:Adult; D000368:Aged; D044966:Anti-Retroviral Agents / Q000627:therapeutic use*; D000946:Antigens, Fungal / Q000276:immunology / Q000494:pharmacology; D000956:Antigens, Viral / Q000276:immunology / Q000494:pharmacology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002175:Candida / Q000201:enzymology / Q000276:immunology*; D016922:Cellular Senescence / Q000276:immunology; D003587:Cytomegalovirus / Q000276:immunology; D003586:Cytomegalovirus Infections / Q000276:immunology / Q000821:virology; D015658:HIV Infections / Q000188:drug therapy / Q000276:immunology*; D015497:HIV-1; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010751:Phosphopyruvate Hydratase / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D012367:RNA, Viral / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology
D044966:Anti-Retroviral Agents; D000946:Antigens, Fungal; D000956:Antigens, Viral; D012367:RNA, Viral; D007371:Interferon-gamma; D010751:Phosphopyruvate Hydratase