Abstract
Killer‐immunoglobulin‐like receptors (KIR) or C‐type lectin‐like receptors are heterogeneously expressed on NK cells and small subsets of T cells and might provide a new diagnostic tool for LGL lymphoproliferations (LGLL). We investigated the diagnostic impact of these cell surface molecules in T‐ and NK‐type LGLL. Using three‐color flow cytometry we examined the expression patterns of KIR (CD158a/b/e/i), CD85j, lectin‐like receptors (CD94, CD161, NKG2A/D) and natural cytotoxicity receptors (NKp30/44/46) in 13 patients with LGLL (10 T‐, 3 NK‐LGLL) and compared them to those of the corresponding lymphocyte subsets in 20 control subjects. The presence of clonal TCR‐gamma rearrangements and of Epstein Barr virus‐ (EBV) DNA were evaluated by PCR.
All patients exhibited an altered expression of NK‐associated markers. KIR were either lacking (6/13) or overexpressed (7/13). CD94 expression was significantly higher in all LGLL. NKG2A expression was significantly higher in NK‐LGLL. Absence or overexpression was observed for NKG2A in T‐LGLL and CD161 in most T/NK‐LGLL. In NK‐LGLL expression of NKp30 and NKp46 was significantly decreased, whereas CD85j was overexpressed.
We consistently found a skewed expression pattern of novel NK markers as a pathological feature of LGLL. These antigens should be included in the diagnostic workup of this rare disease. Copyright © 2006 John Wiley & Sons, Ltd.