Shingles caused by varicella-zoster was regarded as rare disease, mostly related to childhood chickenpox. However, meningoencephalitis caused by varicella-zoster is increasingly recognized as a predominant cause of ME among immunocompetent adults in non-epidemic circumstances. Diagnosis of complications of varicella-zoster, particularly in cases where the disease reactivates after years or decades of latency, are difficult. A rash (shingles) can be present or absent. Symptoms vary, and there is significant overlap in symptoms with herpes-simplex symptoms. Although DNA analysis techniques such as polymerase chain reaction (PCR) can be used to look for DNA of herpesviruses in spinal fluid or blood, the results may
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