Western blotting is a sensitive technique for the detection of anti-PlA1

Western (immuno-) blotting was evaluated as a technique for anti-PlA1 detection, using untreated and chloroquine or low pH-treated platelets. Chloroquine-treated platelet membranes generated the cleanest blots, giving end-point titres of 4000-16,000 for three different anti-PlA1 sera. These titres were between three and eight doubling dilutions higher than those obtained in solid phase, ELISA or indirect immunofluorescence tests. Nitrocellulose strips used for blotting could be stored for at least six months at room temperature without significant loss of PlA1 activity. However, immunoblotting still failed to detect anti-PlA1 in the sera of four of fivePl (A1-) women whose infants were born with neonatal thrombocytopenia of probable alloimmune origin.