Characterization of natural cytotoxic T lymphocytes and natural killer cells in Cuban older adults

Abstract

Abstract Introduction: The Cuban population has a high proportion of older adults and faces age-related changes in the immune system, known as immunosenescence. Natural killer T (NKT) cells and natural killer (NK) cells play an important role in innate inmunity and modulating adaptive immune responses. Their diminished function in older adults contributes to increased susceptibility to infectious diseases, tumors, and autoimmune diseases in this population group. Objective: To characterize distribution of NKT and NK cells in Cuban older adults. Methods: A cross-sectional study was carried out in 30 Cuban older adults, considering age, sex and malignant neoplasm comorbidity as factors of influence on the values of NK and NKT. A linear regression model was used to analyze the data, as well as a two-tailed Mann-Whitney U test to compare independent samples. In addition, odds ratios were used as measures of effect. NK cells and NKT lymphocytes were quantified in peripheral blood using flow cytometry. Results: In the studied populations of NK and NKT cells, age and sex did not show any significant differences. However, most cases exhibited values above the normal reference ranges, with the exception of one female patient. While no significant differences were found in the comparisons by sex and age, higher values of NK and NKT cells were observed in the group under 80 years old and in males. The adequate NK cell numbers in PB might be a protective factor against malignant neoplasms Conclusions: NK and NKT cells play a fundamental role in the regulation of immune response and directly influence the impairment of immune response in older adults, age and sex showed no significant impact on NKT and NK cell counts and percentages. Nevertheless, the presence of adequate NK cell percentages might be a protective factor against malignant neoplasms.