Is there a relationship between anti-HPA-1a concentration and severity of neonatal alloimmune thrombocytopenia?
There is uncertainty about the relationship between anti-HPA-1a levels and severity of neonatal alloimmune thrombocytopenia (NAIT). To investigate this relationship further,the concentration of anti-HPA-1a in HPA-1b homozygous women was determined, using a newly developed quantitative ELISA that uses purified anti-HPA-1a to obtain a standard curve. Seventy-eight samples collected from 22 HPA-1b homozygous pregnant women at various stages of pregnancy were tested. These included five women who had delivered babies with severe NAIT. A national HPA-1a antibody standard (NIBSC 93/710), designated as 1 arbitrary unit/mL (AU/mL),was used in each ELISA to calibrate the purified anti-HPA- 1a, enabling the presentation of results as AU/mL. Moreover, selected samples were also assayed by PAK 12 and their reactivity compared with quantity of antibody. The use of the purified HPA- 1a antibody yielded consistent sigmoid curves, enabling the measurement of HPA-1a antibody concentration in the test s
