Lymphocyte tubular structures in rheumatoid arthritis

SUMMARY Two types of lymphocyte tubular structures were studied by electron microscopy in 80 patients with classic or definite rheumatoid arthritis (RA). Fifteen patients with unequivocal systemic lupus erythematosus (SLE) and 10 healthy persons were studied as controls. Lymphocyte tubulo-reticular structures were found in 13 of the 80 patients with RA and in 10 of the 15 patients with SLE. No tubuloreticular structures were found in any of the healthy subjects. In the RA patients antinuclear antibodies, LE cell phenomenon, and chlorambucil treatment were associated signifi-cantly with these inclusions but disease activity was not related to their presence. In cases in which tubuloreticular structures were present the number of cells containing inclusions was on average much lower in patients with RA than in those with SLE. Lymphocyte tubular parallel arrays were found in all the patients with RA and SLE and in all the healthy persons. In all three groups the average number of cells containing parallel tubular arrays was similar. Since tubuloreticular structures (TRS) in the renal endothelium in systemic lupus erythematosus (SLE) were first described (Gy6key et al., 1969) there have been many reports of their presence in the cytoplasm of human lymphocytes. TRS have been found in the vascular endothelium and lymphocytes in various diseases of apparently independent pathogenesis (Schaff et al., 1973; Landolt et al., 1976) and there has been no convincing explanation for their presence. They have often been found in SLE (Gyorkey et al., 1972; Bariety et al., 1973; Grimley et al., 1973) and TRS in lymphocytes seem to be related to disease activity (Klippel et al., 1974). However, they have been reported in only a few cases of rheumatoid arthritis (RA) (Gyorkey et al., 1972; Bariety et al., 1973). Another type of lymphocyte tubular inclusion are parallel tubular arrays (PTA). These have been found in lymphocytes of healthy persons (Huhn, 1968; Bariety et al., 1971; Brunning and Parkin, 1975), but they are more common in various disease