Relation Between Thyroid Hormone Concentration and Serum Levels of Interleukin-6 and Interleukin-10 in Patients With Nonthyroidal Illness Including Chronic Kidney Disease

Introduction. We evaluated relations between interleukins (IL) IL-6 and IL-10 and euthyroid sick syndrome (ESS) in patients with nonthyroidal illness (NTI). Materials and Methods. Sixty patients and 20 healthy volunteers were recruited. The patients had either chronic kidney disease (CKD), congestive heart failure (CHF), or acute myocardial infarction (MI), distributed equally in 3 subgroups. Serum levels of IL-6 and IL-10, thyroid stimulating hormone (TSH), total T4, and T3 were determined. Results. In the 60 patients with NTI, we detected a significantly lower T3 and T4 levels compared to controls, while TSH level was within the reference range. Also, IL-6 level was substantially higher than that in controls (P < .001) and correlated with T3 (r = -0.620, P < .001) and T4 (r = -0.267, P < .001). Similarly was IL-10 level (P < .001) that correlated with T3 (r = -0.512, P < .001), but not with T4. The ILs correlated positively with each other (r = 0.770, P < .001). Only IL-6 was a predictor of low T3 (P = .001). The proportion of patients with subnormal T3, T4, and TSH levels was highest in those with MI along with greatest IL-6 and IL-10 levels compared to patients with CHF and CKD. Patients with CKD showed the least disturbance in IL-6 and IL-10 despite the lower levels of T3, T4, and TSH in a higher proportion of them compared to patients with CHF. Conclusions. The high frequency of ESS in patients with NTI may be linked to IL-6 and IL-10 alterations. Perturbation of IL-6, and not IL-10, might be involved in the pathogenesis of ESS along with other key players as suggested by our findings in CKD.