Cutaneous T-cell lymphoma (CTCL): Current practices in blood assessment and the utility of T-cell receptor (TCR)-Vβ chain restriction

Background: Accurate quantification of malignant cells in the peripheral blood of patients with cutaneous T-cell lymphoma is important for early detection, prognosis, and monitoring disease burden. Objective: We sought to determine the spectrum of current clinical practices; critically evaluate elements of current International Society for Cutaneous Lymphomas (ISCL) B-1 and B-2 staging criteria; and assess the potential role of T-cell receptor-V beta analysis by flow cytometry. Methods: We assessed current clinical practices by survey, and performed a retrospective analysis of 161 patients evaluated at Yale (2011-2014) to compare the sensitivity, specificity, positive predictive value, and negative predictive value of parameters for ISCL B2 staging. Results: There was heterogeneity in clinical practices among institutions. ISCL B1 criteria did not capture 5 Yale cohort cases with immunophenotypic abnormalities that later progressed. T-cell receptor-V beta testing was more specific than polymerase chain reaction and aided diagnosis in detecting clonality, but was of limited benefit in quantification of tumor burden. Limitations: Because of limited follow-up involving a single center, further investigation will be necessary to conclude whether our proposed diagnostic algorithm is of general clinical benefit. Conclusion: We propose further study of modified B-1 criteria: CD4/CD8 ratio 5 or greater, % CD4(+) CD26(-) 20% or greater, or % CD4(+) CD7(-) 20% or greater, with evidence of clonality. T-cell receptor-V beta testing should be considered in future diagnostic and staging algorithms.