Dominance of Nonmalignant T-Cell Clones and Distortion of the TCR Repertoire in the Peripheral Blood of Patients with Cutaneous CD30+ Lymphoproliferative Disorders

The CD30-positive cutaneous lymphoproliferative disorders (CLPD) include lymphomatoid papulosis (LyP) and primary cutaneous anaplastic large T-cell lymphoma (cALCL). Despite the malign-appearing histology, an excellent prognosis and spontaneous regression of single lesions characterize LyP. Even after years of clinical remission newly erupting lesions often harbor a T-cell clone identical to the initial one. This fact raises the question whether the clonal T-cell population persists in the peripheral blood. Therefore we investigated genomic DNA of 126 samples of lesional skin and peripheral blood from 31 patients with CLPD, obtained during both active disease and clinical remission. We performed molecular genetic analysis by combining T-cell receptor (TCR)-γ PCR with the GeneScan technique and assessed the TCR repertoire in selected blood samples by β-variable complementarity-determining region 3 (CDR3) spectratyping qualitatively and quantitatively. We were able to detect a clonal T-cell population in 36/43 (84%) skin samples and in 35/83 (42%) blood samples. Comparison of the compartments in each patient demonstrated different T-cell clones in skin and blood, suggesting a reactive nature of the clonal T cells in the blood. Moreover, CDR3 spectratyping revealed a restricted T-cell repertoire in the blood, suggesting T-cell stimulation by an unknown antigen.