Differential diagnosis of lymphoid infiltrates in the lungs

: Clinico-morphological and immuno-histological data on 15 cases of marked lymphocytic lung tissue infiltration are presented. The nature of B- and T-lymphocyte distribution, their proliferative activity as well as patterns of distribution of cells synthesizing light chains of immunoglobulins are described. In 12 cases, lymphocytic interstitial pneumonia was diagnosed; it featured distinct boundaries between zones of B- and T-lymphocytes of proliferating and resting cells. However, non-Hodgkin's lymphoma (MALT) detected in 3 cases lacked such a pattern. That might be interpreted as a marker of the particular pathology.