A New Polymerase Chain Reaction–Based Method for the Detection of T-Cell Clonality in Patients With Possible Cutaneous T-Cell Lymphoma

Abstract

THE OFTEN-SLOW evolution of cutaneous T-cell lymphoma (CTCL) and the gravity of the diagnosis of malignant lymphoma pose a special diagnostic problem to dermatopathologists. Immunohistochemistry and molecular studies of the T-cell receptor γ (TCRG) gene are frequently used to corroborate the clinicopathological impression. For the past decade, the Southern blot analysis using T-cell receptor β probes has been the method of choice for the molecular demonstration of clonal T-cell populations. Southern blot analysis, however, is a labor-intensive, unwieldy procedure requiring several days for results. Its sensitivity in detecting a clonal population is at best in the range of 2% to 5% of total nucleated cells, and thus, small clonal T-cell populations in early lesions of mycosis fungoides (MF) can be difficult to detect.^1,2 A new, rapid, and easy technique for the detection of T-cell clonality using polymerase chain reaction (PCR) and single-strand conformation polymorphism (SSCP) was recently developed.³ Our goal was to determine the value of the new PCR test compared with the clinicopathological correlation (CPC) and immunophenotyping.