Gene analysis of pulmonary pseudolymphoma.

The value of gene analysis was assessed in patients with pulmonary pseudolymphoma. Two patients with histopathologic evidence of pseudolymphoma took part in the study. High molecular weight DNA was extracted from resected specimens and digested with restriction enzymes, followed by southern blotting. Gene rearrangement of immunoglobulins and T-cell receptors was investigated using DNA probes against heavy chain (H chain), kappa chain, and lambda chain of immunoglobulin genes and that against the beta-chain of T-cell receptor genes. Both patients with pseudolymphoma showed rearranged bands for the H chain; B-cell lymphoma was diagnosed from the gene analysis. Gene analysis is a valuable method when it is difficult to judge whether the tumor cells are of T-cell origin or B-cell origin in phenotype analysis by immunohistologic studies and when it should be judged whether or not the lymphoid hyperplasia is tumor related.