Immunological profiles of natural killer cells and their subpopulations in overweight and obesity class‑I individuals stratified by two‑dimensional categories of lipid profiles and body mass index

Overweight and obesity remain global health issues that should not be overlooked. They may impair immune health and alter the function of natural killer (NK) cells, immune effectors that may help regulate immune surveillance and associate metabolic inflammation. Therefore, the present case‑control study investigated the immunological profiles of NK cells, both overall and by subpopulations [neural cell adhesion molecule 1 (NCAM1/CD56) staining: Weak (CD56Dim) and strong (CD56Bright)], in 125 Thai participants stratified into five groups by lipid profiles [normal lipid (NL) and dyslipidemia (DL) and body mass index (BMI; normal weight [NW], overweight [OW] and obesity class‑I (OB‑I)]. NK cells' immunological profiles were determined by flow cytometry. It was found that total NK cell percentages were significantly higher in the DL/OB‑I group than in the NL/NW group (P<0.01) and the NL/OW group (P<0.05). Interferon‑gamma (IFN‑γ)‑producing CD56Bright NK cell percentages were also highest in the DL/OB‑I group. BMI correlated positively with total NK cell percentage (R=0.214; P<0.05), CD56Dim NK cell percentage (R=0.217, P<0.05), and IFN‑γ‑producing CD56Bright NK cell percentage (R=0.463; P<0.01). Altogether, the findings demonstrated that NK cell percentage and activation increased markedly with BMI and dyslipidemia. The immunological profiles of NK cells were particularly altered in the DL/OB‑I group, characterized by higher percentages and cytokine‑producing capacity. Therefore, BMI and lipid profiles must be controlled to preserve immunological status and prevent subsequent low‑grade inflammation.