Disease the time between infection and the appearance of symptoms. The latency period is the time between infection and the ability of the disease to spread to another person, which may precede, follow, or be simultaneous with the appearance of symptoms. Some viruses also exhibit a dormant phase, called viral latency, in which the virus hides in the body in an inactive state. For example, varicella zoster virus causes chickenpox in the acute phase; after recovery from chickenpox, the virus may remain dormant in nerve cells for many years, and later cause herpes zoster (shingles). Diseases may be classified by cause,
IgG4-related disease Japanese investigators, notably choosing not to use the term 'systemic' as that might lead to malignant tumours in other organs getting incorrectly diagnosed as being just another manifestation of the IgG4-related condition. However, some experts at the international symposium did express reservations about naming the disease after IgG4, as its role in pathogenesis is questionable and the use of serum IgG4 concentrations as a biomarker is unreliable. An expanded term, 'Immunoglobulin G4-related disease', has sometimes been used also. However, this term was never referenced in the 2012 recommendations for nomenclature, and its use would appear to be erroneous. IgG4-related disease