SBIR-STTR Award

In some patients, phospholipid-binding antibodies have been associated with recurrent venous and/or arterial thrombosis as well as with recurrent fetal loss (the antiphospholipid syndrome, or APS). These antibodies are induced in a variety of clinical circumstances, and it is likely that the above clinical associations are limited only to patients with particular subgroups of antiphospholipid (aPL) antibodies. Antibody subgroups may differ in their affinities for particular phospholipids or in their specificities for particular phospholipid conformations, such conformations being determined by phospholipid-lipid mixtures. It is possible that manipulation of phospholipid antigen concentration or of phospholipid-lipid mixtures in an enzyme-linked immunosorbent assay (ELISA) system may enable more specific identification of patients with APS. With a view to preparing a marketable ELISA kit specifically designed to identify patients with APS, this study will compare ELISA systems with varying concentrations of negatively charged phospholipids and phospholipid-lipid mixtures to determine the system that is most sensitive and specific for identifying APS patients. Materials used in the assay systems will be evaluated for their stability over time to determine their utility in an ELISA kit.

Anticipated Results:
Tests for aPL antibodies are being introduced in laboratories throughout the world. Current methods for detecting these antibodies can be improved if antigens more specific for identification of patients with APS can be determined. A simply designed ELISA kit for identifying APS patients should be readily marketable in the United States, Europe, and elsewhere.National Heart, Lung, And Blood Institute (NHLBI)

The Anti-Phospholipid Syndrome (APS) is a disorder of recurrent arterial or venous thromboses and recurrent fetal loss affecting a small population of young people. These patients are identified by production of relatively high levels of antibodies specific for negatively charged phospholipids. An ELISA assay system using cardiolipin as antigen has been the most popular method of measuring these antibodies. The use of this assay has been hampered by low specificity because of the frequency with which low levels of anticardiolipin (aCL) antibodies are produced in diseased and healthy individuals. In Phase I we sought to identify a phospholipid antigen or mixture of phospholipid antigens which would enable sensitive and specific identification of APS patients (compared to other patient groups in which false positive aCL tests are frequent). Phospholipid antigen coated plates were stable at 4'C for prolonged periods of time making the use of these reagents in an ELISA kit feasible. In Phase II, we plan to assemble, calibrate, and complete the design of a APS kit. Kit materials will be carefully tested for stability.Awardee's statement of the potential commercial applications of the research:Commercial and university laboratories throughout the world have introduced ELISA anti-cardiolipin tests. Relatively few laboratories have experience with assay and current methods can be improved if antigens more specific for identification of patients with the APS can be determined. We will design, study and calibrate a simple ELISA Kit specific for the Anti-Phospholipid Syndrome which can be marketed in the United States, Europe, and elsewhere.National Heart, Lung and Blood Institute (NHLBI)