Both laboratories contributed equally to the study.
IMMUNE HEMATOLOGIC DISEASE
The implementation of surface plasmon resonance technique in monitoring pregnancies with expected fetal and neonatal alloimmune thrombocytopenia
Article first published online: 24 DEC 2012
© 2012 American Association of Blood Banks
Volume 53, Issue 9, pages 2078–2085, September 2013
How to Cite
Bakchoul, T., Bertrand, G., Krautwurst, A., Kroll, H., Bein, G., Sachs, U. J., Santoso, S. and Kaplan, C. (2013), The implementation of surface plasmon resonance technique in monitoring pregnancies with expected fetal and neonatal alloimmune thrombocytopenia. Transfusion, 53: 2078–2085. doi: 10.1111/trf.12051
This work was supported by a grant for TB from the University Hospital Giessen and Marburg GmbH.
- Issue published online: 9 SEP 2013
- Article first published online: 24 DEC 2012
- Manuscript Accepted: 30 OCT 2012
- Manuscript Revised: 9 OCT 2012
- Manuscript Received: 8 JUN 2012
- University Hospital Giessen and Marburg GmbH
Maternal anti-HPA-1a alloantibodies are responsible for most cases of severe fetal and neonatal alloimmune thrombocytopenia (FNAIT). The presence of HPA-1a alloantibodies in maternal blood alone does not predict the fetal platelet (PLT) count, and the predictivity of antibody titers determined by enzyme immunoassays (EIAs) is debated. In contrast to EIA, surface plasmon resonance (SPR) provides information on antibody-binding properties.
Study Design and Methods
Sequential sera from pregnant women with expected FNAIT were assessed for HPA-1a alloantibodies using SPR. Group I (n = 6) was treated with intravenous immunoglobulin (IVIG) and steroids beginning at 19 weeks of gestation (w.g.), and Group II (n = 4) received intrauterine PLT transfusions (IUT) beginning at 22 w.g. Maternal alloantibodies were quantified using an HPA-1a monoclonal antibody (MoAb) as a standard. Antibody avidity was determined as the ratio of B700 (end of the dissociation phase) to B350 (end of the association phase); the area under the curve (AUC) was calculated to determine overall antibody binding.
After 22 w.g., alloantibody characteristics remained stable in both groups, while there was a steep decrease in B700 and B350 values between 16 and 22 w.g. (assessed only in Group I), indicating a decrease in anti-HPA-1a alloantibody concentrations. Interestingly, the AUCs of the last maternal sample before elective delivery appeared to be correlated with fetal and neonatal PLT counts (p = 0.014 and 0.017, respectively).
SPR provides quantitative information on HPA-1a alloantibody characteristics in addition to monoclonal antibody–specific immobilization of platelet antigens. SPR results can be calibrated using a MoAb standard and should be further assessed for a potential correlation with fetal PLT count.