Flow cytometry analysis of lymphocyte subsets in bronchoalveolar lavage: comparison between lung non-Hodgkin lymphomas and reactive diseases

Deepened flow cytometry (FCM) analysis of bronchoalveolar lavage fluid (BALF) cells can disclose clonal B and abnormal T lymphocytes in case of lung involvement in non Hodgkin lymphoma (NHL). The possible role of routine FCM BALF analysis in diagnosing NHL involving the lungs is largely undetermined. To evaluate whether differences exist, within FCM screening of lymphocyte subsets, between BALFs from lung NHL and BALFs from reactive diseases. We compared alveolar leukocyte and lymphocyte data obtained using flow cytometry in 17 lung NHL cases with the median corresponding data detected in 208 controls, matched with cases for computed tomography findings. Absolute leukocyte counts did not differ significantly between cases and controls. As calculated within leukocytes, percentages of total, B, T, CD4+ and CD8+ T lymphocytes, respectively, were significantly higher in B cell NHL cases than in their controls (P = .003,.023,.009,.004, and.020, respectively). Similarly, percentages of total, and CD8+ T lymphocytes, respectively, were significantly higher in T cell NHL cases than in their controls (P = .046 and.027, respectively). Huger BALF lymphocytosis occurs in pulmonary NHLs than in other lung diseases. Possible lymphocyte cutoffs, that could indicate lung NHL and the subsequent need of a second-step BALF staining shortly following the initial screening, should be prospectively attempted.