Viruses and pemphigus: an intriguing never-ending story.

Virus infections and autoimmunity have long been linked. As to pemphigus, many studies have been directed to prove or rule out the possibility of viral induction. Herpesviruses have often been related to the onset or reactivation of pemphigus. The association may be (i) casual, (ii) due to the iatrogenic immunosuppression facilitating opportunistic viral infections or (iii) based on a pathogenic link between the viral presence and the host's dysregulated immune response leading to autoimmunity. Japanese researchers, using real-time polymerase chain reaction, lately detected herpes simplex virus DNA in the saliva from pemphigus patients at the earliest stage of the disease and with no signs or history of herpetic infection, thus confirming the possible existence of cases of pemphigus induced by herpesviruses. These selected cases could be included into the innovative concept of 'paraviral eruptions', where an inciting role for induction may be played by the concomitant intake of certain drugs.