THE CONTENT OF NK CELLS AND THEIR SUBTYPES IN THE CASE OF DRUG-INDUCED JAW OSTEONECROSIS.

The goal of the study is assessing the population structure of lymphocytes and the subpopulation composition of NK cells in the peripheral blood of humans in the case of drug-induced osteonecrosis of the jaw for improving the quality of diagnosis, treatment, and prevention of osteonecrosis of the jaw. Thirty patients were examined, including 15 patients with drug-induced osteonecrosis of the jaw (ONJ), 10 healthy individuals, and five patients with pyoinflammatory diseases of the maxillofacial region, aged 49 to 77. Every four weeks, the patients had been receiving 4 mg intravenous injections of bisphosphonates (the Zometa preparation (zoledronic acid)) for 1.5 - 3 years. The study was performed on a FACS Canto II flow cytometer manufactured by Becton Dickinson (BD), USA. In the patients with ONJ, an imbalance of the NK cell subtypes was observed. As to the common NK cells, the level of subtypes of cytolytic NK cells (CD3-CD16+(or hight)56dim) was elevated, and the level of cytokine-producing cells (СD3-CD16-(or low) 56bright) was reduced, compared to the healthy individuals (p<0.05). In the patients with ONJ, after the surgical treatment, the relative and absolute levels of lymphocytes and the total level of NK cells (CD3-CD16+/56+) normalized on the seventh day. The level of NK cells subtypes did not change after the treatment. This pathology is characterized by a low level of innate protection factors, as evidenced by the reduction of the total population of NK cells, and the imbalance of NK cells subtypes. The imbalance of NK cells (the natural killer cells) was an indicator of unfavorable prognosis for osteonecrosis treatment.