Division of Reproductive Endocrinology, Dept of Obstetrics & Gynecology, 956 Court Avenue, Room D324, Memphis, Tennessee 381632116, USA
1 To whom correspondence should be addressed at: Professor of Obstetrics and Gynecology, 80 Humphreys Center, Suite 307, Memphis, TN 38120-2363, USA. e-mail: wkutteh{at}utmem.edu
Dear Sir,
We appreciate the comments of Drs Sugi and McIntyre. We are aware of the excellent contributions to the literature from these investigators in the field of antiphospholipid antibodies (APA) and, as they noted, appreciate the difficulties in the assay of APA.
Every lot of calf serum is carefully screened and purchased in bulk. As the authors know, there are significant lot-to-lot variations in the optical density obtained in the APA assay from different batches of serum. Each lot is screened with the sera from a known high positive patient with phosphatidylethanolamine (aPE) to achieve similar optical density over time as prior lots of serum.
However, we are amazed that the authors are surprised that phosphatidylinositol (aPI) and phosphatidylglycerol (aPG) were detected independently from anticardiolipin (aCL) and antiphosphatidylserine (aPS). In a specific APA, this is a common observation, and has been reported by us and others. We do believe that each phospholipid can be detected independently based on unique binding site specificity.
Finally, and most importantly, we believe that there is a growing body of literature to suggest that antibodies other that those directed against cardiolipin are clinically significant. Our study is really just one clinicians approach to treatment of these women who have suffered repeated pregnancy losses. Our study does not have the power or the proper study design to definitively answer the questions that have been posed. In the absence of such data, we all must continue to do our best to diagnose and treat these women.