Increased levels of cytokines have been proposed to account for the decreased ATP production and increased lactate during exercise; however, the elevations of cytokine levels are inconsistent in specific cytokine, albeit frequently found. Similarities have been drawn between cancer and CFS with regard to abnormal intracellular immunological signaling. Abnormalities observed include hyperactivity of Ribonuclease L, a protein activated by IFN, and hyperactivity of NF-κB. Endocrine
Evidence points to abnormalities in the hypothalamic-pituitary-adrenal axis (HPA axis) in some, but not all, persons with CFS, which may include slightly low cortisol levels, a decrease in the variation of cortisol levels throughout the day, decreased responsiveness of the HPA axis, and a high serotonergic state, which can be considered to be a "HPA axis phenotype" that is also present in some other conditions, including post-traumatic stress disorder  and some autoimmune conditions. It is unclear whether or not decreased cortisol levels of the HPA axis plays a primary role as a cause of CFS, or has a secondary role in the continuation or worsening of symptoms later in the illness. In most healthy adults, the cortisol awakening response shows an increase in cortisol levels averaging 50% in the first half-hour after waking. In people with CFS, this increase apparently is significantly less, but methods of measuring cortisol levels vary, so this is not certain. Autoimmunity
Autoimmunity has been proposed to be a factor in CFS, but there are only a  few relevant findings so far.
Vocal cord hemorrhage occurs when a blood vessel in the vocal cords ruptures, which results in leakage of blood into the superficial lamina propria and dysphonia (hoarseness). The rupture usually results from overly forceful or incorrect vocalization, and may be a one-time occurrence or occur repeatedly. According to News Medical.net, "professional singers are at an increased risk of vocal hemorrhage, particularly in cases where gruelling performance schedules are followed". The treatment is  vocal rest as failure to rest the voice can result in permanent scarring. == References ==