Natural killer cell proliferation and renal disease: a functional and phenotypic study

We describe a 57-year-old woman who presented with a constitutional syndrome, glomerulonephritis, and lymphocytosis. The phenotypic study, using flow cytometry, showed an expansion of natural killer (NK) cells (CD2+, CD3-, CD16+, CD56+, and CD7+). We performed a functional study of peripheral blood mononuclear cells (PBMCs) and of purified CD16+ cells (NK cells) and CD3+ cells (normal T cells). The expanded NK cell population, CD16+, did not proliferate with phytohemagglutinin (PHA) or anti-CD3 but showed a dose-dependent proliferation with recombinant interleukin-2 (rIL-2) and also proliferated with phorbol dibutyrate. This population showed very strong NK and lymphokine-activated killer cell (LAK) activities. The patient's symptoms resolved spontaneously without treatment. Three years later, however, there is still abnormal renal function, and the expansion of NK cells persists, although with no indication of malignancy. We review the features of the different large granular lymphocyte proliferations and their seldom described relationship with renal disease.