[Morphological evidence of the presence of a bacillus in cell cultures of the synovial membrane from rheumatoid arthritis patients].

34 synovial membranes (SM) from 24 rheumatoid arthritis (RA) patients, and two from osteoarthrosis cases as controls, were studied by culturing the cells on elongated coverslips and Giemsa staining them. 33/34 RA-SM, a 97%, disclosed the presence of a rod-shaped bacterium and its cell wall-deficient forms (CWDB), all adhering to the cells. An external contamination as the organism origin, was ruled out. From one of the RA-SM, a Gram (-), nonfermentative bacillus was isolated, which up to now remains unidentified. This bacillus, when reinoculated onto human embryonic fibroblasts, reproduces the images shown in the rest of the RA-SM. The possibility of this bacillus being the etiological agent of RA is discussed.