Method: We report three RA patients treated with RTX who developed osteoarticular and cutaneous infection due to C fetus.
Result: Age of the patients was 71, 53 and 80 years respectively with a median RA duration of 24, 13 and 19 years. All patients had history of diabetes mellitus. Patient n°2 also suffered of COPD and patient n°3 of BOOP and hypertensive cardiomyopathy. All patients were co-treated with corticosteroids, with a dosage of 10mg/D and DMARDs. Patients had received respectively 4, 1 and 2 RTX cycle before C fetus infection. Gamma globulin amount before the last RTX infusion was 5, 5.8 and 6.9 g/L. C fetusinfection occurred within a delay of 4 month [0.75-36] before the last RTX infusion. Patient n°1 developed left knee prosthesis infection, patient n°2 cellulitis of the right leg, and patient n°3 arthritis of the right elbow. Only one patient had fever. CRP amount was 16.5, 2 and 50mg/dl and median WBC was 13 200, 15 400 and 13 200. All patients had severe B lymphopenia (respectively 0, 2 and 7 CD19+ B lymphocyte /mm3) and hypogammaglubulinemia (respectively 5, 5.8 and 3.2 g/L of gammaglobulin) at the onset of infection. Evolution was good in all patients after antibiotic therapy and discontinuation of RTX treatment. (Table 1)
Conclusion: This represents the first report of a series of C. fetus infections in RA patients treated with RTX. Our observations highlight a crucial role of B cell in C fetus infection.
Interestingly, the 3 patients were treated with corticosteroids with a dosage of 10mg/d and had hypogammaglobulinemia, both before RTX infusion and when infection occurred which have been recently shown to be risk factors of severe infections in RA patients treated with RTX (1). The three patients had also diabetes mellitus that has probably promote the infection.
C fetus infections are certainly under diagnosed, mainly because this germ growth requires microaerophylic culture conditions (2). Our observations show that clinicians should be aware of the possibility of C fetus infection in RA patient treated with RTX and should ask for specific research of microaerophilic organism in case of “culture negative” monoartritis and/or cellulitis, especially when risk factors of severe infections such as hypogammaglobulinemia or diabetes mellitus are present.
1-Gottenberg et al. Arthritis Rheum. 2010.
2- Blaser et al. Clin Infect Dis. 1998.
Disclosure: A. Meyer, None; A. Theulin, None; E. Chatelus, None; C. Sordet, None; R. M. Javier, None; H. Chifflot, None; J. E. Gottenberg, None; J. Sibilia, <10,000$, 5 .