Differential surface marker expression in patients with CD-16+ lymphoproliferative disorders: in vivo model for NK...

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-1A) and HLA class II+ phenotype did correlate with NK function in contrast to a CD-16+, Leu-7+, Leu-19- (NKH-1A) and HLA class II- phenotype. Of importance was the fact that the CD-16+, HLA class II+ cells did not express CD-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 approach for examining NK differentiation.