Objective: To investigate the prevalence of human herpesvirus 8 (HHV-8; Kaposi sarcoma-associated herpes-virus) infection in patients with lymphoproliferative skin diseases such as large-plaque parapsoriasis (LPP) and mycosis fungoides compared with inflammatory cutaneous conditions or healthy control subjects. Design: A survey study was undertaken in 123 subjects with various clinical conditions. Setting: All patients had been seen in the Dermatology Department of the San Gallicano Dermatology Institute, Rome, Italy, in the last 2 years. Patients: Forty-five patients with inflammatory or autoimmune cutaneous diseases, 50 healthy control subjects, 10 patients with LPP, 12 patients with mycosis fungoides, and 6 patients with classic Kaposi sarcoma were included in the study. Main Outcome Measures: The prevalence of HHV-8 infection was investigated with serologic studies using the gold standard assay based on body cavity-based B-cell lymphoma-1 cells latently infected with HHV-8. The presence of HHV-8 conserved sequence, corresponding to open reading frame 26, was also assessed in the peripheral blood and lesion tissue samples from patients with lymphoproliferative cutaneous diseases with nested polymerase chain reaction. The presence and distribution of cell types infected with HHV-8 in the lesion tissues was determined with immunohistochemical staining with the monoclonal antibody directed against the latent nuclear antigen-1 of HHV-8 encoded by open reading frame 73. Results: In healthy control subjects and patients with inflammatory skin diseases, 13.9% were found to have antibody against HHV-8, consistent with the seroprevalence population in Italy. A highly significant association of HHV-8 infection and LPP was found (100%) compared with mycosis fungoides (25%). The peripheral blood mononuclear cells in 8 of 10 patients with LPP were found to harbor viral sequences at nested polymerase chain reaction, whereas none of them had a detectable serum viral load. All LPP lesion tissue samples were positive for HHV-8-encoded open reading frame 26, and the presence of HHV-8-infected cells was confirmed by immunohistochemistry profiles performed on paraffin-embedded tissues from 4 of 10 patients. The positive cell types included endothelial cells and the infiltrating dermal lymphocytes, characteristic hallmarks of LPP. Analysis of T-cell receptor γ chain rearrangements in lesion tissue from our patients confirmed the lack of a significant association between T-cell clonality and LPP. Conclusion: These data suggest that HHV-8 may play a role in the onset of LPP, a disease whose cause and evolution are still undefined and which has often been considered the early stage of mycosis fungoides.
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