Acquired factor VIII:C inhibitor (IgG) and positive direct Coombs' test (IgM) in a patient with lung carcinoma

Abstract
A 73-year-old man with lung squamous-cell carcinoma simultaneously developed a factor VIII:C inhibitor and a transient positive direct Coombs' test. The factor VIII:C inhibitor was characterized as a mixture of IgG1, IgG2, IgG4 with kappa and lambda light chains. The Coombs' test was IgM-specific. blood transfusions (packed red cells), cyclophosphamide and prednisone. Bleeding subsided without factor VIII-replacement therapy. Before death, in spite of the tumour-mass progression, factor VIII:C was normal.