Effect of IL-27 on activity of bone marrow NK cells of patient with B-chronic lymphocytic leukemia in vitro

Functional defect in immune cells is the prominent feature in hematological malignancies that lead to the expansion of tumor cells. Using immunostimulatory cytokines is one of the new therapeutic approaches. This study aimed to investigate the effect of IL-27 on the activity of bone marrow-NK cells of chronic lymphocytic leukemia (CLL) patients in vitro.

10 ml of bone marrow aspirate samples were collected from 5 patients with CLL and isolated monocular cells using Ficoll-Hypaque density gradient. NK cells were then purified by MACS technique. The mononuclear cells were cultured in RPMI with or without recombinant human IL-27 (100ng/ml) for 48 hours. Expression of CD69 was assessed on purified and unpurified NK cells (BMCs) using flow cytometry. Also, purified NK cells were adjacent to the target cells as the K562 cell line in E:T ratios of 2.5:1, 5:1 and 10:1, then the target cell survival was assessed by flow cytometry using Annexin V/7-AAD.

The levels of CD69 expression on purified NK cells increased in IL-27 treated group in compared to the control (P=0.05). However, the expression level of CD69 in unpurified NK cells did not significantly increase with IL-27 treatment (P=0.06). Moreover, in the ratio of E/T:10, the NK cell cytotoxicity rate increased significantly (P=0.03), but this difference was not significant in the E:T ratios of 2.5 and 5.

IL-27 cytokine increased NK cell function and cytotoxic activity against malignant cells in CLL. The results of this study can be used in clinical trials in the future.