Lymphocytes infiltrating synovial membranes were characterized in eight patients with proliferative rheumatoid synovitis. Surface immunoglobulins were studied with use of immunofluorescence, and the C3 receptor was detected by adherence of red cells coated with antibody and complement - both are B-cell markers. Spontaneous rosette formation with sheep erythrocytes was used as a T-cell marker. To obtain viable lymphocytes in suspension, the villous synovium of five of these patients was digested with collagenase and deoxyribonuclease. Populations enriched in lymphocytes could be obtained by velocity sedimentation. Whereas only 9 to 35 per cent of lymphocytes bore surface immunoglobulins, the majority (70 to 85 per cent) formed sheep-erythrocyte rosettes. Cells bearing the C3 receptor constituted a distinct minority of synovial lymphocytes in frozen-tissue sections, and were found in follicle-like accumulations. These data indicate that the predominant infiltrating lymphocyte in proliferative rheumatoid synovitis is a T cell.

The capacity of lymphoid cells from nonsensitized mice to lyse antibody-coated target erythrocytes in vitro does not require the presence of thymus-derived or thymus-dependent lymphocytes. Thus, spleen cells from thymus-deprived mice and spleen cell populations from which thymus-dependent lymphocytes had been removed were fully competent to mediate destruction of antibody-coated target cells. However, prior treatment of spleen cell populations with antibody to kappa chains diminished this function, suggesting a role for bone marrow-derived lymphocytes.

Heat-aggregated guinea pig γ-globulin was shown to bind to the surface membrane of a subclass of guinea pig T lymphocytes. Cells of this subpopulation were identified as T lymphocytes because these cells did not stain for surface Ig (a B-cell marker) but did form spontaneous E-rosettes with rabbit erythrocytes (a T-cell marker). A strikingly high proportion of such aggregate-binding (Agg+), E-rosette-forming (E-rosette+), but surface Ig-negative (Ig-) cells were found in an inflammatory exudate. Thus purified peritoneal exudate lymphocytes (PELs) are known to consist of over 90% T cells, and 59% of these cells bound aggregates. 10% of these Agg+ Ig- E-rosette+ cells were found in draining lymph node cell populations and none in thymus cell populations. The high frequency amongst PELs suggested that these Aggregate+ Ig- E-rosette+ cells might be activated T cells as these are known to occur in high proportion in PEL populations. Confirmatory evidence for this postulate was provided by the striking increase (from 10% to 46%) of Ig- E-rosette+ cells that bound aggregates when lymph node cells were activated by antigen stimulation in vitro.

Chronic lymphocytic leukemia (CLL) is thought to be a malignancy of bone marrow-derived (B) lymphocytes, since the leukemic cells from a majority of patients bear easily detectable membrane-bound immunoglobulin (Ig) (1), possess a complement (C3) receptor (2), and do not bind sheep erythrocytes (3). Since in most studies (1, 3-5), but not all (6), the cells from an individual patient bear Ig restricted to a single light chain class, it is suspected that the CLL lymphocytes represent the progeny of a single clone of B cells.The present study provides support for the clonal proliferation of CLL cells by demonstrating in a single patient that the Ig on virtually all of the CLL cells possess the same idiotypic (variable region) determinants. The anti-idiotypic serum, prepared against a circulating paraprotein, reacted only with the paraprotein and the surface Ig on the CLL cells and not with a variety of other serum or cell-bound Igs. Materials and MethodsSource and Isolation of Lymphocytes. J . T . is a 61-yr old male with an 18 mo history of chronic lymphocytic leukemia and an |gG paraprotein. The peripheral lymphocyte count has been maintained at _< 20,000 mature lymphocytes per mm 3 by two, brief courses of chemotherapy. The IgG paraprotein has persisted at 50-60 mg/ml throughout his course.Lymphocytes were collected from peripheral blood by the methods of BSyum (7). CLL lymphocytes from 23 different patients were either used fresh or frozen viably (8) and stored at -82°C for periods of up to 9 mo before use. Viability of the thawed cells ranged from 40-82%. Preliminary experiments demonstrated that viably frozen cells maintained their surface immunoglobulin. Lymphocytes (PBL) from 16 nonhematologic patients were used fresh.