Correlation between clonotypic T-cell receptor beta chain variable region (TCR-Vβ) gene expression and aberrant T-cell antigen expression in cutaneous T-cell lymphoma

Immunohistochemical studies can augment the clinicopathologic diagnosis of cutaneous T‐cell lymphoma (CTCL). Our goal was to determine whether a panel of 11 T‐cell receptor (TCR) beta chain variable region (Vβ) monoclonal antibodies (moAbs) could consistently identify clonal T‐cell populations within CTCL skin infiltrates, and whether these cells exhibited aberrant T‐cell antigen expression. Biopsies from 24 CTCL and 3 parapsoriasis patients were analyzed. Of the 27 patients, 4 (15%) demonstrated T‐cell clonality by restricted TCR‐Vp moAb staining. The Vp+ restricted cells expressed aberrant antigen profiles. Overall, aberrant antigen profiles were detected in 18/24 (75%) CTCL patients. Vβ18 moAb crossreacted with a 85 kD protein produced by basal and suprabasal keratinocytes. We conclude: 1) Restricted TCR‐Vp expression correlated with aberrant T‐cell antigen profiles; 2) In the absence of a complete panel of TCR‐Vp moAbs, localization of aberrant T‐cell antigen expression can be useful in identifying malignant T‐cells within CTCL skin infiltrates; 3) The detection sensitivity and specificity of the currently available TCR‐Vβ moAbs may limit their utility to consistently detect clonal T‐cell populations in CTCL skin biopsies; 4) A 85 kD protein present on basal and suprabasal keratinocytes is recognized by Vβ18 moAb and may be related to immune function (s) of the epidermis.