Discrepancy in the aPS/PT-IgG titers using 2 ELISA kits in patients with several kinds of collagen diseases

Abstract

ELISA kits for the measurement of phosphatidylserine-dependent antiprothrombin antibodies (aPS/PT) have recently been developed by two companies, MBL Corporation and Cosmic Corporation, in Japan. We evaluated the relationship between aPS/PT titers using these two ELISA kits in patients with systemic lupus erythematosus (SLE), primary antiphospholipid syndrome (PAPS) and systemic scleroderma (SSc). Namely, Cosmic aPS/PT titers were found to be significantly correlated with MBL aPS/PT titers in patients with SLE and PAPS, but not so in patients with SSc(r=0.99, 0.99, and 0.07, p<0.0001, <0.0001, and NS, respectively). The results suggest that commercially available aPS/PT ELISA kits lead to different results and thus, we should pay attention to the clinical significance of aPS/PT titers in certain patients associated with a variety of underlying diseases such as SSc.