A group led by Dr. Vincent Descamps at University Denis Diderot in Paris, France has found preliminary evidence that PCR saliva testing is useful for the detection of herpesvirus reactivation among patients with the drug hypersensitivity syndrome known as “Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS).” The study included 5 patients who met definite criteria for DRESS and 15 controls (5 immunosuppressed patients and 10 healthy adults). The PCR assay used in the study demonstrated shedding of HHV-7, EBV, HHV-6, and CMV. Interestingly, DNA viral loads were found to be similar when comparing blood and saliva samples. Neither HHV-6 nor CMV were detected in control samples, while significant production of HHV-7 and EBV was demonstrated among controls.
Herpesvirus reactivation, in particular HHV-6, is a hallmark of drug hypersensitivity conditions such as DRESS and DIHS, and has been shown to contribute to increasingly severe clinical outcomes compared to DIHS/DRESS patients who do not experience virus reactivation (Tohyama 2007, Pritchett 2012). Although the HHV-6 reactivation mechanism in patients with DIHS remains unclear, many believe that under conditions of transient immunosuppression HHV-6 may be reactivated from latently infected monocytes. Therefore, drug-induced immune reaction accompanied by skin inflammation may cause an increase in the number of monomyeloid precursors and facilitate HHV-6 reactivation (Tohyama & Hashimoto 2011).
Dr. Descamps’ group has initiated a large therapeutic prospective study to determine the effectiveness of various treatment regimens in limiting the clinical severity of DIHS/DRESS. In the study, patients with severe DRESS & betaherpesvirus reactivation will be treated with a combination of corticosteroids and antiviral medication (ganciclovir). Severe DRESS without betaherpesvirus reactivation will be treated with corticosteroids and IVIG.