Antiphospholipid antibody production during Mediterranean spotted fever.

Antiphospholipid antibodies (aPLA) were discovered during the course of Mediterranean spotted fever (MSF) caused by Rickettsia conorii and characterized by endothelial cell (EC) damage resulting from this organism's tropism for EC. In two MSF patients, two types of aPLA were identified: antiphosphatidylethanolamine antibodies detected by immunological methods and lupus anticoagulant detected by clotting assays. The persistence of both aPLA for several months after the acute phase and clinical recovery might correspond to a durable immunological response to membrane damage of EC caused by R. conorii. Their possible role in the pathophysiology of microthrombi formation observed during MSF remains to be elucidated in a study on a larger number of patients.