S. Panzer et al., MATERNAL ALLOIMMUNIZATION AGAINST FETAL PLATELET ANTIGENS - A PROSPECTIVE-STUDY, British Journal of Haematology, 90(3), 1995, pp. 655-660
Neonatal alloimmune thrombocytopenia (NAIT) is induced by maternal all
oantibodies to fetal platelet antigens, This prospective study was car
ried out to evaluate the incidence of anti-platelet antibodies in 933
mother-child pairs where the mother and child were typed for the human
platelet antigens (HPA)-1, -2, -3, -5, Sera from mismatched mother-ch
ild pairs were screened for anti-platelet antibodies, anti-HLA class I
and blood group ABO IgG antibodies. Platelet-specific antibodies were
anti-HPA-3a in one and anti-HPA-5b in 17 neonates, respectively, All
these neonates had normal platelet counts, One woman had autoreactive
antibodies. Anti-HLA class I and anti-blood group A IgG antibodies wer
e detected in live and four neonates, respectively, born with a platel
et count < 150 x 10(9)/l. None of the 11 homozygous HPA-1b mothers bec
ame immunized against their heterozygous offspring. The maternal HLA-a
llotypes HLA-DR52 and -DR6, typically found in individuals immunized a
gainst HPA-1a and -5b, respectively, were found in three of 11 HPA-b/b
non-responders and eight of the anti-HPA-5b responders. The results i
ndicate that a risk for NAIT due to HPA-2 and -3 alloimmunization is l
ow. The HLA allotypes do not predict the risk for NAIT due to HPA-1 or
-5 alloimmunization. Maternal anti-HPA-5b antibodies do not correlate
with the platelet count in the neonate.