Evaluation of fatigue state with virus-related novel biomarkers in obstructive lung diseases

Background Fatigue is an important clinical state and limits physical, mental activities in the patients with chronic lung diseases. However mechanisms and evaluation methods of fatigue are not well established. Recently reactivation of human herpesvirus (HHV)6/7 and HHV6 related molecules, named SITH-1 (Small protein encoded by the Intermediate Stage Transcript of HHV6-1) and its serum antibody (aSITH-1Ab) have been studied as novel biomarkers for fatigue.1),2) Fatigue due to chronic stress can cause increase of HHV6/7 DNAs in saliva, and aSITH-1Ab in blood of patients with mental disturbance. The HHV-related biomarkers could be good candidates to evaluate the pathological fatigue. Method To evaluate fatigue state, patients in stable conditions with COPD, asthma (BA) and BA COPD overlap syndrome (ACOS) were enrolled. The fatigue markers, depression score, and inflammation markers were measured. Result 60 patients were enrolled (mean age=60±14.8y, M/F=45/15, COPD/BA/ACOS=15/32/14). The rates (%) of high HHV DNA in saliva, meaning fatigue state, in COPD/BA/ACOS were 40/36/30, for both viruses equally. aSITH-1Ab positive rates (%) in COPD/BA/ACOS were 15.8/57.9/26.3. The markers for systemic inflammation were higher in COPD/ACOS than BA alone. Conclusion 30∼40% of the patients with COPD/BA/ACOS were estimated as fatigue. The patients with COPD (COPD/ACOS) showed higher systemic inflammation than BA alone, whereas those with BA (BA/ACOS) showed higher prevalence of mental disturbance than COPD alone. 1) Kondo K. et al. Journal of Virology 2002; 76: 4145-4151 2) Kondo K. et al. US Patent Application US 2013/0137088 A1 May 30, 2013.