Availability of NK cell expansion agent combined with recombinant IL‑2 and IL‑15 stimulation on the expansion and high‑purity of NK cells in patients with immune‑related pancytopenia in�vitro

Natural killer (NK) cells are a group of large granular lymphocytes that play an important regulatory role in innate immunity and adaptive immunity. Immune‑related pancytopenia (IRP) is a type of pancytopenia resulting from bone marrow hematopoietic cells that were destroyed or suppressed by auto‑antibodies. The specific mechanism of IRP is not clear. In the present study, it was identified that the percentage of NK cells in peripheral blood lymphocytes was decreased in patients with IRP. Subsequently, high purity NK cells were extracted from 6 untreated patients with IRP using the immunomagnetic beads sorting, magnetic‑activated cell‑sorting method, which were then cultured then in RPMI‑1640 medium containing 20% FBS. NK cell expansion agents, with or without recombinant interleukin (IL)‑15, were used to amplify high‑purity NK cells on the basic of recombinant IL‑2. Expression of the activated receptors NKG2‑D type II integral membrane protein (NKG2D) and natural killer cell p46‑related protein (NKp46), and the inhibitory receptors CD158a and NKG2‑A/NKG2‑B type II integral membrane protein (NKG2A), in CD56+ NK cells were detected by flow cytometry before and after cell culture. It was observed that treatment with an NK cell expansion agent combined with the stimulation of recombinant IL‑2 and recombinant IL‑15 could increase the number whilst maintaining the purity of NK cells. There were no significant changes in the expression of NKG2D, NKp46, NKG2A and CD158a in patients with IRP before and after NK cell culture. This new amplification method lays a foundation for clinical NK cell immunotherapy and anti‑tumor applications.