T-Cell clonality in pityriasis lichenoides et varioliformis acuta: a heteroduplex analysis of 20 cases

Abstract

Background: Cutaneous lesions of pityriasis lichenoides et varioliformis acuta (PLEVA), a T cell-mediated cutaneous inflammatory condition, are clinically similar to lymphomatoid papulosis (LyP), leading some authors to hypothesize that they are part of the same spectrum of lymphoproliferative disorders, although reports of the development of cutaneous lymphoma in patients with PLEVA are not as frequent as they are for patients with LyP. Furthermore, unlike in cases of LyP, no systematic search for a dominant T-cell clone has been carried out in cases of PLEVA, whereas clones have been detected in a few cases of PLEVA using mainly Southern blot analysis.

Objective: To investigate T-cell clonality in a series of archival PLEVA lesions. TISSUES: Archival paraffin-embedded biopsy specimens from 20 clinically and pathologically typical cases of PLEVA were selected.

Main outcome measure: Identification of a dominant T-cell clone by polymerase chain reaction and heteroduplex analysis targeted on the TCRgamma gene. Peripheral blood mononuclear cells (PBMCs) and Jurkat cells were used as negative and positive controls. Serial dilutions of Jurkat T-cell lymphoma DNA in PBMC DNA were used to assess the sensitivity of the method.

Results: Analysis of 13 (65%) of 20 PLEVA biopsy specimens revealed the presence of a dominant T-cell clone. Positive and negative controls confirmed the specificity of the procedure. The sensitivity was determined to be between 1% and 5% of the total T-cell infiltrate.

Conclusions: This study provides further evidence for the presence of a dominant T-cell clone in skin lesions of some patients with PLEVA and supports the hypothesis that PLEVA is part of the spectrum of clonal-T-cell cutaneous lymphoproliferative disorders.