ABSTRACT
We evaluated relations between interleukins [IL] IL-6 and IL-10 and euthyroid sick syndrome [ESS] in patients with nonthyroidal illness [NTI]. 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. 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. 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