The exceptional association of Hairy cell leukemia (HCL) and monoclonal large granular lymphocyte (LGL) proliferation is reported in the same patient. Immunophenotypic analysis, showed that most of the PBMC expressed CD3 and HNK-1 molecules, while in the bone marrow biopsy an infiltration by CD22 +/CD25 + lymphoid cells was detectable. The monoclonal rearrangement of βTTCR genes in the PBMC, suggests that the increased LGL is not reactive. Nevertheless, a possible interaction between the two entities is proposed. The high sIL-2R serum levels, related to proliferation of hairy cells, might account for the lack of NK activity observed in the LGL.
Keywords: Hairy cell leukemia; large granular lymphocyte proliferation; soluble IL-2R.