Prognostic significance of a polymerase chain reaction-detectable dominant T-lymphocyte clone in cutaneous lesions of patients with mycosis fungoides.

Although mycosis fungoides (MF) is considered to be an indolent lymphoma, survival is highly influenced by TNM stage. At diagnosis, most MF patients present with early stage disease and a high probability of long-term survival. Treatment is generally directed towards skin lesions, and achievement and duration of complete responses are variable. A dominant T-cell clone is detectable in the cutaneous lesions of 60% of patients. The aim of this study was to determine whether the presence of a T-cell clonal population influences the clinical course of the disease after topical therapy. Cutaneous biopsies from 68 patients were histologically diagnosed as MF and T-cell clonality was analyzed by in vitro amplification of TCR-gamma chain gene rearrangements (polymerase chain reaction gamma [PCRgamma]). After a median follow-up of 48 months, response to treatment was clinically assessed. Age, sex, duration of symptoms before diagnosis, type of cutaneous lesions (T stage), TNM stage, and PCRgamma were evaluated as predictive factors of response to treatment in univariate and multivariate analyses. Univariate analysis demonstrated that T1 cutaneous lesions (P = .05) and PCRgamma negativity (P = .007) were associated with a higher complete remission rate. Using multivariate analysis, T stage (relative risk, 3.13; P = .06) and PCRgamma (relative risk, 4.4; P = .01) remained independent significant predictive parameters of response. In conclusion, T stage and cutaneous PCRgamma at diagnosis are the two predictive parameters of treatment response for MF. Therefore, the cutaneous PCRgamma findings should be considered in the analysis of future therapeutic trials.