Expression of the chemokine receptor CXCR3.

(A) Normal tonsil shows staining of approximately 50% of T cells in the interfollicular areas for CXCR3. B cells, in follicles and mantle zones, are negative. (B) Angiocentric T-cell lymphoma of the lung shows diffuse positivity for CXCR3 in the angioinvasive component. (C) Histiocyte-rich T-cell (lymphoepithelioid) lymphoma shows a mixture of predominantly small tumor lymphocytes and numerous CD68-positive epithelioid histiocytes (inset, left). Tumor cells are positive for CXCR3. Histiocytes show strong expression of Mig (inset, right).