ANALYSIS OF IMMUNOGLOBULIN CLASS, IGG SUBCLASS AND TITER OF HPA-1A ANTIBODIES IN ALLOIMMUNIZED MOTHERS GIVING BIRTH TO BABIES WITH OR WITHOUT NEONATAL ALLOIMMUNE THROMBOCYTOPENIA
C. Proulx et al., ANALYSIS OF IMMUNOGLOBULIN CLASS, IGG SUBCLASS AND TITER OF HPA-1A ANTIBODIES IN ALLOIMMUNIZED MOTHERS GIVING BIRTH TO BABIES WITH OR WITHOUT NEONATAL ALLOIMMUNE THROMBOCYTOPENIA, British Journal of Haematology, 87(4), 1994, pp. 813-817
We analysed the titre and isotype composition of antibodies produced b
y mothers giving birth to babies with or without neonatal alloimmune t
hrombocytopenic purpura (NAITP) and patients with post-transfusion pur
pura (PTP). All these individuals produced an antibody specific for th
e HPA-1a allotype present on the platelet glycoprotein IIb-IIIa (GPIIb
-IIIa). Sera from mothers who gave birth to thrombocytopenic babies (g
roup 1, n = 36), non-thrombocytopenic babies (group 2, n = 4) or from
PTP patients (group 3, n = 3) were tested by an indirect-ELISA. Result
s indicated no evident differences in the isotype composition or titre
of the antibodies from the three groups of sera. The antibody titre r
anged from 1:120 to 1:3500. Antibodies with the IgG1 subclass were pre
sent in all sera. Most sera contained IgG1 alone (24/43 sera tested) o
r in combination with IgG3 (10/43). IgG2 was never present and only th
ree sera showed intermediate reactivity with anti-IgG4 MAb. Few sera (
nine sera from groups 1 and 2) were weakly positive when tested with t
he anti-IgM antibodies. These results suggest that neither the titre n
or the isotype composition can be used to predict the severity or the
occurrence of thrombocytopenia in newborns.