Circulating lymphoma cells in patients with B & T non-Hodgkin's lymphoma detected by immunoglobulin and T-cell receptor gene rearrangement.

We studied peripheral blood mononuclear cells from 50 patients with active B- and T-cell non-Hodgkin's lymphoma by DNA hybridisation. Nineteen patients (38%) had circulating clones of cells detected by immunoglobulin gene rearrangement (17 patients) or T-cell receptor gene rearrangement (2 patients) with JH and J beta 2 probes. Lymphoma tissue and peripheral blood were studied simultaneously in 22 patients, 9 of which had a circulating clone of cells in peripheral blood. In 7 patients the gene rearrangement in lymphoma tissue and peripheral blood mononuclear cells was identical. However, in 2 patients both heavy chain and light chain gene rearrangements were different in tissue and peripheral blood. The incidence of peripheral blood involvement was commonest in advanced CSIII & IV disease (54%) compared to CSI & II disease (18%) (P less than 0.05), and in low grade (45%) compared to intermediate and high grade lymphoma (31%) (difference not statistically significant). Only 4 patients had definite lymphoma cells seen on peripheral blood smear. The presence of circulating lymphoma cells correlated with conventional assessment of bone marrow involvement although circulating clones were detected in 30% (12/40) of patients with apparently normal bone marrow.