Does Rh immune globulin suppress HLA sensitization in pregnancy?

• Published in: Transfusion (Philadelphia, Pa.) Vol. 53; no. 9; pp. 2069 - 2077
• Main Authors: Kaufman, Richard M., Schlumpf, Karen S., Wright, David J., Triulzi, Darrell J.
• Format: Journal Article
• Language: English
• Published: Hoboken, NJ Blackwell Publishing Ltd 01.09.2013; Wiley; Wiley Subscription Services, Inc
• Subjects: Adult; Aged; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Blood. Blood and plasma substitutes. Blood products. Blood cells. Blood typing. Plasmapheresis. Apheresis; Confidence intervals; Cross-Sectional Studies; Female; HLA Antigens - immunology; Humans; Logistic Models; Medical research; Medical sciences; Middle Aged; Pregnancy; Rho(D) Immune Globulin - immunology; Studies; Transfusions. Complications. Transfusion reactions. Cell and gene therapy; Pregnancy; Human; HLA-System; Immunoglobulins; Transfusion; Major histocompatibility system; Female; Sensitization; Woman; Class I histocompatibility antigen
• ISSN: 0041-1132; 1537-2995; 1537-2995
• DOI: 10.1111/trf.12049

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. Study Design and 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). Conclusion 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.