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#13
DO ANTI-PHOSPATIDYL ETHANOLAMINE AND ANTI-PHOSPHATIDYL CHOLINE ANTIBODIES INCREASE SENSITIVITY OR CREATE MORE HAVOC?
John D. May, B.S., Jeffrey Dlott, M.D., Shirley Johnson, B.S., Sue Faucett, B.S., Nancy Higgins, B.S. and Zacharie Brahmi, Ph.D.. Indianapolis IN, USA, Clarian Health Partners, 46202, Medicine.

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The antiphospholipid syndrome (APS) is a loosely defined type of autoimmune disease the etiology of which is still unresolved. Our laboratory has been testing for antiphospholipids for a number of years using an in-house method. In this study, therefore, we did a head to head comparison between our in-house method and commercial kit where the results are semi-quantitative. The in-house method permits the detection 3 classes of antibodies (IgM, IgG, IgA) directed against phosphatidyl serine (PS), cardiolipin (CL), phosphatidyl choline (PC), and phosphatidyl ethaloneamine (PE) whereas the kit detects the 3 classes of Abs directed against PS and CL only. When the results with CL and PS were examined there were 29 number of discrepant cases: 11 of 29 resulted in no difference secondary to the difference in the method used (i.e. intent to treat or repeat testing based on moderate titers-kit or mOm >6 in-house) ; 8 of the remaining 18 cases were considered low level (5/18 mOm = 5, 3/18 were low titer (kit); 10 of 18 were moderate to high resulting in a change of intent to treat (5 due to in-house and 5 due to kit results). There were no cases where an IgA titer > 6 mOm or was not detected by another isotype. By the in-house-method, we also examined 1016 patients. 433 were negative and 583 were positive for any of the PL tested. Of the 583 positive ones, 45% were negative for PS and CL, but positive for either PE or PC. These results emphasize that the presence of antiphospholipid Abs, especially those directed against PE and/or PC should be interpreted with caution and that the treatment of such patients should be initiated only when warranted by the clinical context.