title: Humoral immune responses to Pneumocystis jirovecii antigens in HIV-infected and uninfected young children with pneumocystis pneumonia.
abstract: BACKGROUND
  Humoral immune responses in human immunodeficiency virus (HIV)-infected and uninfected children with Pneumocystis pneumonia (PcP) are poorly understood.
  
  
  METHODS
  Consecutive children hospitalized with acute pneumonia, tachypnea, and hypoxia in South Africa were investigated for PcP, which was diagnosed by real-time polymerase chain reaction on lower respiratory tract specimens. Serum antibody responses to recombinant fragments of the carboxyl terminus of Pneumocystis jirovecii major surface glycoprotein (MsgC) were analyzed.
  
  
  RESULTS
  149 children were enrolled of whom 96 (64%) were HIV-infected. PcP occurred in 69 (72%) of HIV-infected and 14 (26%) of HIV-uninfected children. HIV-infected children with PcP had significantly decreased IgG antibodies to MsgC compared to HIV-infected patients without PcP, but had similar IgM antibodies. In contrast, HIV-uninfected children with PcP showed no change in IgG antibodies to MsgC, but had significantly increased IgM antibodies compared to HIV-uninfected children without PCP. Age was an independent predictor of high IgG antibodies, whereas PcP was a predictor of low IgG antibodies and high IgM antibodies. IgG and IgM antibody levels to the most closely related MsgC fragments were predictors of survival from PcP.
  
  
  CONCLUSIONS
  Young HIV-infected children with PcP have significantly impaired humoral immune responses to MsgC, whereas HIV-uninfected children with PcP can develop active humoral immune responses. The children also exhibit a complex relationship between specific host factors and antibody levels to MsgC fragments that may be related to survival from PcP.
authors.affiliation: Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America.
authors.forename: Kpandja
authors.initials: K
authors.lastname: Djawe
authors.affiliation: Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America ; Research Service, Veterans Affairs Medical Center, Cincinnati, Ohio, United States of America.
authors.forename: Kieran R
authors.initials: KR
authors.lastname: Daly
authors.affiliation: Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America.
authors.forename: Linda
authors.initials: L
authors.lastname: Levin
authors.affiliation: Department of Pediatrics and Child Health, University of Cape Town, Cape Town, South Africa.
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Zar
authors.affiliation: Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America ; Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America ; Research Service, Veterans Affairs Medical Center, Cincinnati, Ohio, United States of America.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Walzer
mesh_terms: D000367:Age Factors; D000946:Antigens, Fungal / Q000276:immunology*; D002648:Child; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D056724:Immunity, Humoral / Q000502:physiology*; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D045363:Pneumocystis carinii / Q000276:immunology*; D011020:Pneumonia, Pneumocystis / Q000150:complications* / Q000276:immunology
chemical_list: D000946:Antigens, Fungal; D007074:Immunoglobulin G; D007075:Immunoglobulin M