Functionality of natural killer cells in obese asthma phenotypes

Area of Science:

• Immunology
• Respiratory Medicine
• Cell Biology

Background:

• Obesity-associated asthma (OA) is a severe asthma phenotype with poor response to inhaled steroids.
• OA may comprise subtypes: early-onset allergic (EoOA) and late-onset non-allergic (LoOA).
• The role of Natural Killer (NK) cells in OA pathogenesis is not well understood.

Purpose of the Study:

• To investigate the role and function of NK cells in different subtypes of obesity-associated asthma.
• To compare NK cell characteristics between OA patients and obese non-asthmatic controls.
• To explore potential therapeutic targets for improving OA treatment.

Main Methods:

• Flow cytometry was used to analyze NK cell subsets, cytotoxic activity, and intracellular cytokine production (IFN-γ, IL-10, IL-13, IL-17) in peripheral blood.
• Expression of NK cell activatory receptors (NKG2D, NKp46i, NKp44) was assessed.
• The effects of IL-12 and IL-23 stimulation on NK cells were evaluated in obese non-asthmatic controls, EoOA, and LoOA patients.

Main Results:

• Body Mass Index was negatively correlated with CD69 expression on NK cells.
• NKG2D receptor expression was significantly lower in CD56dim NK cells of asthma patients.
• IL-12 stimulation increased NKp44 expression in EoOA and controls, and IL-10 in LoOA and controls.
• Intracellular IL-17 levels were higher in allergic OA, and NK cytotoxicity was reduced in LoOA compared to EoOA.

Conclusions:

• Obesity-associated asthma patients exhibit impaired NK cell receptor expression, activation, and reduced cytotoxicity.
• Significant differences in NK cell function exist between EoOA and LoOA subtypes.
• These findings support the development of personalized treatment strategies for steroid-resistant OA.