Association of NK cell subsets and cytotoxicity with FCGR3A gene polymorphism in functional NK cell deficiency

OBJECTIVE: The purpose of this study was to assess the association between clinical, laboratory, and functional analyses and polymorphism in the FCGR3A gene in individuals with functional NK cell deficiency. METHODS: A total of 15 functional NK cell deficiency patients and 10 age -matched healthy controls underwent NK cell subgroup, cytotoxicity, and FCGR3A whole-exome analysis with next -generation sequencing. RESULTS: Three different NK cell subsets (CD56(bright)CD16(neg), CD56(bright)CD16(int), and CD56(dim)CD16(hi)) were identified. No statistically significant difference was found in the ratio of CD56(bright)CD16negcells between patients and controls. CD56(bright)CD16(int)and CD56(dim)CD16(hi)ratios were found to be significantly lower in patients. As a result of NK cell cytotoxicity analysis, a proportional decrease of K562 amount between patients and controls was found to be statistically significant (p<0.001). In the FCGR3A whole-exome analysis, all patients were found to be homozygous mutant for the c.526G > T (p.V176F) in exon 4, while three patients were homozygous wild type and 12 patients were heterozygous for the c.197T>A (p.L66H) in exon 3. CONCLUSION: In this study, a group of pediatric patients with suspected functional NK cell deficiency were evaluated and the findings indicated that NK subsets, cytotoxicity results, and FCGR3A gene polymorphism were found to be correlated with the clinical features. We conclude that this kind of study might contribute to follow-up the patients in time.