Fig 1: Detection of autoantibodies against C1q and MBL in RA patients. (A) C1q, (B) MBL, and alpha-1 antitrypsin as negative control were immobilized on microtiter plate wells. After blocking, serum samples diluted 1:50 were added. In the case of C1q, high salt concentration buffer was used and in the case of MBL 10 mM EDTA was used to exclude unspecific binding, as described in Materials and methods. Bound IgG was detected by HRP-conjugated anti-human IgG. Selected samples are shown: positive patient samples, some negative patient samples and controls. For full datasets please refer to Supplementary Figure 1 . Data are mean ± SEM of two experiments.