Factor VII inhibitor.

Factor VII inhibitor activity was identified in a 66 year old man with probable bronchogenic carcinoma. Initial studies indicated a normal partial thromboplastin time (PTT) and a prothrombin time (PT) prolongation which increased with incubation. PT correction failed to occur with 50 per cent normal plasma in vitro and 2 U of fresh frozen plasma in vivo, indicating inhibitor activity. Specific factor assay levels fell within normal limits except for a factor VII level of 30 per cent. Subsequent evaluation with antiglobulin studies suggested an inhibitor of immunoglobulin G [IgG] origin.