APOH and autoimmune polyendocrinopathy: More than 80% (26 of 32) of the β2GPI-reactive T cell clones recognized an epitope within Domain I, while only 19% (6 of 32) recognized an epitope within Domains IV and/or V. Interestingly, the predominance of Domain I-specific T cell clones in atherosclerotic lesions of primary APS patients differs from the predominant Domain V specificity observed in peripheral T cells of APS patients (34, 35, 38).