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 (V beta) monoclonal antibodies (moAbs) could consistently identify clonal T-cell populations within CTCL skin infiltrates, and whether these cell 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-V beta moAb staining. The V beta + restricted cells expressed aberrant antigen profiles. Overall, aberrant antigen profiles were detected in 18/24 (75%) CTCL. Patients. V beta 18 moAb crossreacted with a 85 kD protein produced by basal and suprabasal keratinocytes. We conclude: 1) Restricted TCR-V beta expression correlated with aberrant T-cell antigen profiles: 2) In the absence of a complete panel of TCR-V beta 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-V beta 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 V beta 18 moAb and may be related to immune function(s) of the epidermis.