Pseudolymphoma of the lung: lymphoid subsets in the lung mass and in peripheral blood.

Studies of the lymphocyte markers in a case of pseudolymphoma of the lung indicate a non-neoplastic nature of the lymphoid infiltrate. The relative proportions of T and B cells and of the markers for the various subsets of both populations reflect the morphologically mixed character of the cellular infiltrate of the lung mass. Moreover, an imbalance of T cell subsets was observed in the peripheral blood: the numbers of T cells with receptors for IgM (TM) were persistently decreased while an increase of the values of T lymphocytes with receptors for IgG (TG) was noted. In addition an altered immunologic status of the patient was indicated by the in vivo impairment of cellular immunity as demonstrated by the failure to respond to common antigens and to become sensitized to 1-chloro-2,4-dinitrobenzene (DNBC).