title: Demonstration of frequent occurrence of clonal T cells in the peripheral blood but not in the skin of patients with small plaque parapsoriasis.
abstract: Clinical, immunohistological, and molecular biological data suggest the chronic dermatosis small plaque parapsoriasis (SPP) to be a precursor of mycosis fungoides (MF). However, most data are contradictory and confusing due to inexact definition of SPP. Recently, clonal T cells were detected in skin and blood samples of early MF. Because demonstration of identical T-cell clones in skin and blood of SPP patients would indicate a close relationship of SPP to MF, we investigated the clonality of skin and blood specimens from 14 well-defined SPP patients. By a polymerase chain reaction (PCR) amplifying T-cell receptor gamma rearrangements and subsequent high-resolution electrophoresis, clonal T cells were detected in 9 of 14 initial and 32 of 49 follow-up blood samples, but in 0 of 14 initial skin specimens. Even a clone-specific PCR showing the persistence of the initial blood T-cell clone in 20 of 20 follow-up samples, failed to detect the T-cell clone in the skin. In 2 patients, the clonal T cells were shown to be CD4(+). For the first time, the majority of SPP patients was shown to carry a T-cell clone in the peripheral blood. Although a relation between circulating clonal T cells and SPP cannot directly be proven by the applied techniques, our results indicate blood T-cell clonality to be a characteristic feature of SPP and CTCL because analysis of multiple controls and clinical workup of our SPP patients excluded other factors simulating or causing a clonal T-cell proliferation. A sufficient cutaneous antitumor response but also an extracutaneous origin of the T-cell clones might explain the failure to detect skin infiltrating clonal T cells.
authors.affiliation: Department of Dermatology, University Hospital Charité, Humboldt University of Berlin, Germany.
authors.forename: J M
authors.initials: JM
authors.lastname: Muche
authors.forename: A
authors.initials: A
authors.lastname: Lukowsky
authors.forename: J
authors.initials: J
authors.lastname: Heim
authors.forename: M
authors.initials: M
authors.lastname: Friedrich
authors.forename: H
authors.initials: H
authors.lastname: Audring
authors.forename: W
authors.initials: W
authors.lastname: Sterry
mesh_terms: D000368:Aged; D002454:Cell Differentiation / Q000276:immunology; D006801:Humans; D008875:Middle Aged; D010267:Parapsoriasis / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D016133:Polymerase Chain Reaction; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics / Q000276:immunology*; D012867:Skin / Q000276:immunology* / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology / Q000473:pathology*
chemical_list: D016692:Receptors, Antigen, T-Cell, gamma-delta