Pattern of platelet-associated immunoglobulin (classes and IgG subclasses) in childhood immune thrombocytopenic purpura

Platelet-associated Ig classes and IgG subclasses were studied by a semiquantitative platelet ELISA test in 17 children with immune thrombocytopenic purpura (ITP). An elevation of PAIg was found in 94% of the children. In nearly all cases increased amounts of PAIgG of subclass G1 was seen, and in half of the cases increased amounts of PAIgM were also seen. No statistical difference in the composition of PAIg classes and PAIgG subclasses in acute and in chronic ITP was found. However, a correlation of increased amount of PAIgG3 and very low platelet count (20 x 10(9)/l) was observed.