The detection of both IGH rearrangements and CD expression in BALF cells has been shown to aid in diagnosing pulmonary B-cell lymphoma: it revealed B-cell clonality as well as an increase in B-cell (CD19- or CD20-positive) lymphocytes to over 10% of total BALF lymphocytes3,12–14. The gene discussed is CD19; the disease is B-cell non-Hodgkin lymphoma.