Serum interleukin 6 and ferritin levels are the independent risk factors for pneumonia in elderly patients

Pneumonia is a common infection in elderly patients. We explored the correlations of serum interleukin-6 (IL-6) and ferritin (SF) levels with immune function/disease severity in elderly pneumonia patients. Study subjects included 151 pneumonia/58 healthy geriatrics, with their age/sex/body mass index (BMI)/disease course and severity/blood pressure/C-reactive protein (CRP)/procalcitonin (PCT)/smoking status documented. The disease severity was evaluated by pneumonia severity index (PSI). T helper 17 (Th17)/regulatory T (Treg) cell ratios and IL-6/SF/immunoglobulin G (IgG)/Th17 cytokine (IL-21)/Treg cytokine (IL-10) levels were assessed using flow cytometry/ELISA. The correlations between these indexes/independent risk factors in elderly patients with severe pneumonia were evaluated by Spearman/multivariate logistic regression analyses. Patients showed obvious differences in smoking and CRP/PCT levels. Pneumonia patients exhibited up-regulated Th17 cell ratio and serum IL-6/SF/IL-21/IL-10/IgG levels, down-regulated Treg cell ratio, and more evident differences were noted in severe cases. Serum IL-6/SF levels were positively correlated with disease severity, immune function, and IL-21/IL-10/IgG levels. Smoking history and IL-6/SF levels were identified as independent risk factors in severe pneumonia geriatrics. Collectively, serum IL-6 and SF levels in elderly pneumonia patients were conspicuously positively correlated with disease severity and IL-21/IL-10/IgG levels. CRP, PCT, IL-6, and SF levels were independent risk factors for severe pneumonia in elderly patients.