Antibodies to neutrophil granulocyte myeloperoxidase and elastase: autoimmune responses in glomerulonephritis due to hydralazine treatment.

Autoantibodies against myeloperoxidase and elastase were found in a study of nine patients who had developed glomerulonephritis after treatment with hydralazine, but not in patients who were treated with hydralazine without side-effects. Circulating IgM isotype antibodies against myeloperoxidase, and IgM and IgG anti-elastase, were mainly present during the initial months after withdrawal of the drug. By contrast, IgG isotype antibodies against myeloperoxidase, initially found in seven patients, had increased in concentration and were present in all patients at follow-up after 4-12 years.