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Seventeen patients with well compensated chronic renal failure undergoing periodic hemodialysis were studied with regard to absolute number of T and B lymphocytes, spontaneous and PHA induced lymphocyte blastogenesis both with autologous and homologous compatible plasma. A normal lymphocyte count as well as a normal relative and absolute number of T and B lymphocytes was found in most cases. Spontaneous blastogenesis was normal. Lymphocyte response to PHA was reduced both with autologous and homologous plasma, but the depression was more relevant when autologous plasma was used in culture. The authors discuss these findings with respect to available data, particularly concerning inhibitory factors in uraemic plasma.

Certain properties of the bond between lymphocytes and mouse red blood cells were studied. The turnover of the receptor on the lymphocytes of twelve healthy subjects was evaluated. After two hours of incubation in a medium devoid of additives the receptor is released and its resynthesis is completed in twenty-four hours. In experiments employing proteolytic enzymes inhibition of rosette formation is observed, whereas neuraminidase, under the same experimental conditions, significantly increases the number of rosette forming cells. The percentage of mouse rosette forming cells in nineteen patients affected with chronic lymphatic leukaemia was then evaluated (17 with type B and 2 with type T). On the basis of these cases and other recently published data, an ontogenetic explanation for the appearance of this receptor is proposed.

Two different cellular populations among the circulating lymphocytes were separated by using a technique based on the T lymphocytes capacity to form nonimmune rosettes with sheep red blood cells. The first population (P) is essentially composed of T lymphocytes, the second (population S) is made up mainly of type B lymphocytes. This technique was applied in the study of circulating lymphocytes in 11 patients with chronic lymphocytic leukaemia and was satisfactory both for good reproducibility and for its ability to obtain vital separate lymphocytes. Normal reactivity to PHA and PWM of population P and normal capacity to form E rosettes with SRBC were found. In mixed culture of T lymphocytes stimulated by B cells of the same patient significant blastic response was observed.

In 29 bronchogenic, 22 esophageal carcinomas and 17 glioblastoma peripheral mononuclear cells cytotoxicity toward chicken red blood cells was studied under three different sets of conditions: spontaneously induced, PHA induced, or mediated by antibodies toward target cells lysis. Cultures were 48 hours. While the cytotoxicity induced by mitogen and that medicated by antibody are diminished when compared to the control groups, spontaneous cytotoxicity shows values significantly higher in all the tumoral forms examined. Kinetically this type of lysis shows an already increased release of isotope after 24 hours and a steady rise in the successive hours. After depletion of adherent cells the mononuclear elements lose most of their lytic power. This datum, which contrasts with the diminished spontaneous cytotoxicity toward tumoral cells frequently described in the course of neoplasm, underlines the heterogenicity of the element responsible for SCMC and the diverse effects that the disease provokes on cell function.

In twelve patients with active sarcoidosis we attempted to explain the nature of reduced release on interleukin-2 (IL-2) and the consequent impairment in lymphoproliferative in vitro responses. The addition of exogenous IL-2 containing supernatants was unable to completely restore the defective uptake of 3H-Thymidine suggesting that an impairment of IL-2 producer cells is not enough to explain the in vitro hyporesponsiveness of sarcoid lymphocytes. We also found a reduced number of precursors of IL-2 responder cells, as defined by peripheral blood lymphocytes bearing Tac determinant following in vitro stimulation with mitogens. The abnormalities of both IL-2 producer cells and precursors of IL-2 responder cells in peripheral blood of patients with sarcoidosis are discussed, stressing the importance of the concept of compartmentalization of T lymphocytes in this disease.

In 22 cases of myeloma and 12 cases of benign paraproteinemia the functional situation of circulating lymphocytes was studied. The technique used was the incorporation of 3H-Thymidine after PHA stimulation. E rosette formation and immunoglobulin bearing cells were evaluated. A reduction of 3H-Thymidine incorporation in the blastic cells was seen in the patients with myeloma (2,942 +/- 421 cpm/10(6) lymphocytes in respect to 13,182 +/- 920 of the control group). The difference was statistically significant: p less than 0.001. In benign monoclonal gammopathies the reduction was moderate and was at the limits of the significance: 9,482 +/- 1,100. The percentage of E rosettes and of immunoglobulins bearing cells was normal. The different behaviour of the blastic response in vitro in the two groups of patients tested confirms that the respective condition of the immunocompetent system is clearly different. A possible interpretation of this type of behaviour is discussed.