title: Does Rh immune globulin suppress HLA sensitization in pregnancy?
abstract: BACKGROUND
  How Rh immune globulin (RhIG) prevents sensitization to D antigen is unclear. If RhIG Fc delivers a nonspecific immunosuppressive signal, then RhIG may inhibit sensitization to antigens other than D. HLA antibody prevalence was compared in previously pregnant D- versus D+ women to investigate whether RhIG suppresses HLA sensitization.
  
  
  METHODS
  In the Leukocyte Antibody Prevalence Study (LAPS), 7920 volunteer blood donors were screened for anti-HLA and surveyed about prior pregnancies and transfusions. A secondary analysis of the LAPS database was performed.
  
  
  RESULTS
  D- women not more than 40 years old (presumed to have received antenatal with or without postpartum RhIG in all pregnancies) had a significantly lower HLA sensitization rate than D+ women (relative risk, 0.58; 95% confidence interval [CI], 0.40-0.83). When stratified by deliveries (one, two, three, or four or more), D- women not older than 40 were HLA sensitized less often than D+ women in every case. In contrast, a clear relationship between D type and HLA sensitization was not seen in older previously pregnant women whose childbearing years are presumed to have preceded the use of routine RhIG prophylaxis. In a multivariable logistic regression model, D- women not more than 40 years old remained significantly less likely to be HLA sensitized compared with D+ women after adjusting for parity, time from last pregnancy, lost pregnancies, and transfusions (odds ratio [OR], 0.55; 95% CI, 0.34-0.88).
  
  
  CONCLUSIONS
  Consistent with a nonspecific immunosuppressive effect of RhIG, younger previously pregnant D- women were less likely than previously pregnant D+ women to be HLA sensitized.
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts; Westat, Rockville, Maryland; Institute for Transfusion Medicine, Pittsburgh, Pennsylvania.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Kaufman
authors.forename: Karen S
authors.initials: KS
authors.lastname: Schlumpf
authors.forename: David J
authors.initials: DJ
authors.lastname: Wright
authors.forename: Darrell J
authors.initials: DJ
authors.lastname: Triulzi
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006680:HLA Antigens / Q000276:immunology*; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D011247:Pregnancy; D018029:Rho(D) Immune Globulin / Q000276:immunology*
chemical_list: D006680:HLA Antigens; D018029:Rho(D) Immune Globulin