A novel, noninvasive diagnostic probe for hydroa vacciniforme and related disorders. Detection of latency-associated Epstein-Barr virus transcripts in the crusts

Objective: To establish a new diagnostic method for Epstein-Barr virus (EBV)-associated cutaneous disorders. Design: Skin biopsy is usually required to confirm the latent EBV infections in cutaneous lesions of EBV-associated NK/T-cell lymphoproliferative disorders, including hydroa vacciniforme (HV) and hypersensitivity to mosquito bites (HMB). We have devised a novel, noninvasive method to detect EBV-encoded small RNA (EBER), BamHI A rightward transcripts (BARTs) in the skin crusts and scales of such patients. Patients: Six patients with EBV-associated cutaneous lesions were enrolled in the present study, including three patients with HV, one with HV-like eruptions and chronic active EBV infection, and two with EBV-associated cutaneous lymphoma. Main outcome measures: RNA was extracted from the crusts obtained from the cutaneous lesions by forceps, converted to cDNA, and processed for polymerase chain reaction (PCR) amplification with a specific set of primers. The PCR products were assayed by a DNA sequencer. Results: Intact RNAs were successfully extracted from the crusts as well as control materials. EBER1 and BARTs RNAs were detected in all 7 crusts, and in 6 of 7 crusts of EBV-associated cutaneous diseases, respectively. One of 23 crusts from non EBV-associated diseases was positive for EBER1 RNA. The sensitivity and specificity of our assay for latent EBV infection were 100% and 95.8% for EBER1 RNA, and 85.7% and 100% for BARTs mRNA, respectively. The correct DNA sequence for EBER1 and BARTs was confirmed in the PCR products by a direct sequencing method. Conclusions: Our procedure may be of use as a biomarker for EBV-associated cutaneous lesions, including HV, HMB, and NK/T-cell lymphomas.