Serum cytokine values and fatigue in chronic hepatitis C infection

Abstract

Patients with chronic hepatitis C infection often experience fatigue. In many clinical situations, an association between fatigue and altered serum cytokine levels has been found. Altered cytokine levels in patients with hepatitis C have not shown a correlation with the degree of serum transaminase elevation or pathological change on liver biopsy. The aim of our study was to examine whether there was an association between abnormal serum cytokine levels and fatigue in patients with compensated chronic hepatitis C. Patients referred to a tertiary care hepatology clinic who were hepatitis C antibody positive and who had elevated alanine aminotransferase (ALT) levels were eligible for entry into the study. A control group was also included. Subjects in both groups who had characteristics other than hepatitis C that were known to alter cytokine values and/or cause fatigue were excluded. Patients completed a validated questionnaire to determine their fatigue severity score (FSS). Bioassays were used to measure interleukin (IL)-1, IL-6 and tumour necrosis factor-alpha (TNF-alpha) levels in early morning serum samples taken from patients and controls. Altered cytokine values were defined as those more than two standard deviations above the mean control value. Data was analysed using SPSS, version 8.01. Of the 78 patients with chronic hepatitis C who participated in the study, 19 (24%), 24 (30%) and 45 (56%) had elevated levels of IL-1, IL-6 and TNF-alpha, respectively, compared with only two (6%) of the control group who had elevation of any of the three cytokines. No correlation was found between the FSS and serum cytokine levels, when analysed singly or in combination, in patients with chronic hepatitis C. Hence, alteration in early morning serum levels of IL-1, IL-6 and TNF-alpha in patients with chronic hepatitis C infection and elevated ALT levels bear no correlation with the symptom of fatigue.