Lupus inhibitors following bone marrow transplant.

Lupus inhibitors have been reported in a number of pathologic states in which there is a disruption of normal immunoregulation. We report here the development of new lupus inhibitors following bone marrow transplantation. Retrospective analysis of 1292 patients undergoing transplantation at the University of Minnesota over a 10 year period demonstrated newly recognized lupus inhibitors in 3% of the patients. These inhibitors were usually detected in the first 1-2 months after transplant. They occurred more frequently in children, with a particularly high incidence in patients with Hurler syndrome. The development of inhibitors was associated with the use of cyclosporine A (CsA) or T depletion for GVHD prophylaxis, with the use of busulfan/cytoxan as a preparative regimen (which includes phenytoin for seizure prophylaxis) and with the occurrence of viral infections. Lupus inhibitors were not associated with development of GVHD, or with any diagnosis other than Hurler syndrome. Thrombotic complications were rare as would be expected in this severely thrombocytopenic population. The incidence of lupus inhibitors that we recognized may substantially underestimate the true incidence as frequent routine coagulation studies were not performed in these patients. Prospective evaluation of lupus inhibitors during bone marrow transplant may provide insight into the pathogenesis of these inhibitors in other disease states.