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The lectin peanut agglutinin (PNA), which interacts specifically with D-galactosyl residues, was studied for its binding to human normal and malignant lymphoid cells at various stages of differentiation. As previously reported, PNA binds to thymocytes; however, it does not interact with the prothymocytes which precede the cortical thymocyte differentiation stage. No mature peripheral cells in any of the lymphoid organs bind PNA. In contrast to the normal T differentiation pathway, the expression of the PNA-binding site does not seem to coincide with that of T cell characteristics in the various malignant lymphoid cells studied. We therefore conclude that more information is needed about the nature of the PNA-binding site before it can be used as a differentiation marker in malignant lymphoid cells.

Lymphocytes were separated from the synovial fluid of 34 arthritic patients. The majority of lymphocytes rosetted with SRBC and were thus of T origin. A proportion of these cells were activated as indicated by their high 3H-thymidine incorporation in vitro, the formation of "stable" E rosettes, and their ability to attach to autologous monocytes and to human cells. Such attached activated T cells enhanced the cytotoxic activity of monocytes. Human and murine-activated T cells generated in mixed lymphocyte cultures also attached to cell lines of the same species, and after their attachment they enhanced the cytotoxic activity of monocytes and natural killer cells. It is suggested that one of the possible roles of activated T cells in immunologically damaged tissues is the attraction of circulating nonspecific killer cells to the site of the response.

A subcutaneous intraperitoneal proslysis has been successfully implanted in three chronic uraemic patients. Fifty peritoneal dialyses have been done during 6-3 patient-months, without complications. During this short experience, peritonitis was not seen at all. The patients' acceptance of the prosthesis was good. Lack of abdominal tubes or bags is a remarkable technical improvement of this device.