title: In vivo decrease in the expression of complement receptor 2 on B-cells in HIV infection.
abstract: OBJECTIVE
  To investigate changes in the expression of complement receptor 2 (CR2) on B-cells from HIV-infected individuals. CR2 is the C3d/Epstein-Barr virus receptor and has been implicated in B-cell activation. Changes in its level of expression may therefore be associated with B-cell dysfunction.
  
  
  METHODS
  Cross-sectional study of HIV-infected adults and age-matched control donors.
  
  
  METHODS
  The percentage expression and mean fluorescence intensity of CR2 (and three additional markers: CD19, CD69, and a standard antigen designation: HLA-DR) was measured on CD20+ B-cells using a two-color flow cytometric assay.
  
  
  RESULTS
  This study demonstrated a highly significant (P = 0.0001) decrease in the percentage co-expression of CR2 on CD20+ B-cells in HIV-infected individuals, compared with control donors. The mean percentage of CD20+ cells co-expressing CR2 was 71% (s.d., +/- 15%) in the HIV-seropositive patients and 94% (s.d., +/- 4%) in the control group. The pattern of CR2 expression in a number of the patients suggested a decrease in antigen density on the cells. Decreased expression of CR2 did not correlate with disease stage (asymptomatic, AIDS-related complex, or AIDS), nor with CD4+ T-cell percentage or absolute count, in the seropositive group.
  
  
  CONCLUSIONS
  The evidence for a role for CR2 in B-cell activation suggests that its decreased expression, which we have demonstrated in HIV-seropositive individuals, may be associated with the B-cell dysfunction observed in HIV infection. Our finding that expression of this marker is decreased even in asymptomatic patients is consistent with reports of early B-cell defects in such individuals. Further investigation of this possible association may shed some light on both the increased incidence of bacterial infections in HIV-infected adults and children and their impaired responses to certain immunizations.
authors.affiliation: Department of Pediatrics, Rush-Presbyterian-St Luke's Medical Center, Chicago, Illinois 60612.
authors.forename: M E
authors.initials: ME
authors.lastname: Scott
authors.forename: A L
authors.initials: AL
authors.lastname: Landay
authors.forename: T F
authors.initials: TF
authors.lastname: Lint
authors.forename: G T
authors.initials: GT
authors.lastname: Spear
mesh_terms: D000328:Adult; D001402:B-Lymphocytes / Q000276:immunology*; D015415:Biomarkers / Q000097:blood; D005260:Female; D015658:HIV Infections / Q000276:immunology*; D006679:HIV Seropositivity / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D017464:Receptors, Complement 3d / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D017464:Receptors, Complement 3d