Changes in lymphoid organs, peripheral blood and in homing of lymphocytes after administration of local anaesthetics.

The newly synthetized local anaesthetics of the carbanilate type--pentacaine and heptacaine, and the currently used trimecaine have been previously found to exhibit markedly different effects on immune reactions in vitro and in vivo when administered in equitoxic doses. These compounds are now assayed for their influence on the weight and cell count in lymphoid organs, on peripheral blood leucocyte count and homing of 51Cr-labelled syngeneic lymph node cells. We have found that the weight and cell count in the thymus, spleen, lymph nodes, bone marrow and the levels of peripheral leucocytes are reduced after administration of pentacaine, whereas heptacaine and trimecaine have no effect on these parameters. In contrast to heptacaine and trimecaine, pentacaine significantly reduces also the homing of lymph node cells to the recipients' lymph nodes and increases their homing to bone marrow.