Occurrence of cold agglutinin disease in RA patient during etanercept therapy successfully treated with rituximab.

, 81 infliximab naive RA patients and 47 healthy subjects as controls. At the same time and apart from the purposes of that study, we also had done a pathergy test in those subjects who agreed to participate, with the aim of determining the effect of the pathergy phenomenon on the response of BS patients to the tuberculin test. Informed consent was obtained from all subjects. The study was approved by the ethical committee of Istanbul University, Cerrahpasa Medical School. Eighty BS and 61 RA patients and 38 healthy controls participated. The tuberculin test was administered with the Mantoux technique, using 5 IU of purified protein derivative (PPD) solution, which was injected intradermally into the forearm by a nurse. The pathergy test was done at three sites on each forearm by inserting six sterile 20-gauge needles intradermally, on the same day as the tuberculin test. Both the tuberculin test and the pathergy reaction were evaluated 48 h later, by two independent observers in a blinded manner. Subjects put their arms through a curtain and their hands were covered to prevent the observers from recognizing the subjects, or any deformities revealing the diagnosis. PPD reaction was evaluated by measuring the transverse diameter of the induration. A positive pathergy test was defined as a papule or a pustule at the insertion site of the needle. The number of subjects with a positive PPD test (!10 mm) in each group was compared and the relationship between PPD positivity and the pathergy phenomenon was sought. The number of patients with a positive pathergy reaction, a positive PPD test and the mean PPD induration of each group are shown in Table 1. The mean diameter of the PPD induration was lower among RA patients (H 2df ¼ 20.1, P < 0.001, Kruskal–Wallis) when compared with BS patients and healthy controls. The mean indurations in BS patients and healthy controls were similar (H 1df ¼ 2.0, P ¼ 0.163, Kruskal–Wallis). Inter-group comparisons revealed that mean PPD induration was similar among BS patients and healthy controls (Mann–Whitney U ¼ 1207, P ¼ 0.163). PPD indurations in both BS patients and healthy controls were higher than in RA patients (Mann–Whitney U ¼ 1595, P < 0.001 and Mann–Whitney U ¼ 568.5, P < 0.001, respectively). The number of patients with a positive PPD was also lower among RA patients than the other two groups (2 ¼ 19.246, P …