Differential surface marker expression in patients with Cd-16⁺ lymphoproliferative disorders: In vivo model for NK differentiation

In this study, we report on three patients, each with a CD-16⁺ lymphoproliferative disorder. Peripheral blood lymphocyte from all three patients were evaluated for lymphocyte morphology, natural killer (NK) function, and surface marker expression. In addition, two-color flow cytometric analysis was performed to determine the phenotype of the CD-16⁺ cells. Our findings indicate that the presence of increased numbers of CD-16⁺ cells alone is not a good predictor of NK activity. However, we observed a differential expression of the HLA class II molecules DR and DQ on the CD-16⁺ cells obtained from these patients that was associated with NK function. Hence, a CD-16⁺, Leu-7^-, Leu-19⁺ (NKH-1_A) and HLA class II⁺ phenotype did correlate with NK function in contrast to a CD-16⁺, Leu-7⁺, Leu-19^- (NKH-1_A) and HLA class II-phenotype. Of importance was the fact that the Cd-16⁺, HLA class II⁺ cells did not express ED-25 or TFR, nor did they mediate cytotoxicity against solid tumor targets, suggesting that these CD-16⁺ cells are not activated. Thus, in contrast to previous studies of NK ontogeny that utilized in vitro activated NK cells, studies of patients with CD-16⁺ lymphoproliferative disorders may provide an alternative aspproach for examining NK differentiation.