Quinidine-induced thrombocytopenic purpura: clinical presentation in relation to drug-dependent and drug-independent platelet antibodies.
We have studied the clinical course of quinidine-induced thrombocytopenia in relation to the presence of drug-dependent (dd-ab:s) and drug-independent antibodies in 14 patients. Thrombocytopenia was reversible in 9 d after discontinuation of quinidine treatment in 10 patients. In four it lasted more than 1 month. Drug-dependent antibodies of IgG class were detectable in seven patients: in six by an immunofluorescence test applying flow cytometry and in one patient by a monoclonal antibody-immobilized platelet protein assay (MAIPA) only. The dd-ab:s of this patient had glycoprotein (GP) IIb/IIIa specificity. Five of the six patients with dd-ab:s by immunofluorescence test had GPIb/IX-specific dd-ab:s by MAIPA. They recovered within 5 d after discontinuation of the drug. All four patients with prolonged thrombocytopenia had elevated platelet-associated IgG (PAIgG) in the acute phase as studied by a direct platelet immunofluorescence test. The remaining five patients displayed a relatively rapid clinical recovery but less uniform pattern of immunological findings. The results suggest that patients with GPIb/IX-specific dd-ab:s recover promptly despite an acute and profound thrombocytopenia. Another sub-group with prolonged thrombocytopenia had persistently elevated PAIgG during the convalescent phase.
Nieminen
U
U
Finnish Red Cross Blood Transfusion Service, Helsinki.
Kekomäki
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001792:Blood Platelets / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D008875:Middle Aged; D010980:Platelet Membrane Glycoproteins / Q000276:immunology; D011696:Purpura, Thrombocytopenic / Q000139:chemically induced* / Q000276:immunology; D011802:Quinidine / Q000009:adverse effects* / Q000276:immunology; D013997:Time Factors
D007074:Immunoglobulin G; D010980:Platelet Membrane Glycoproteins; D011802:Quinidine