Molecular detection of circulating Sezary cells in patients with mycosis fungoides: could it predict future development of secondary Sezary syndrome? A single-institution experience

Abstract

While the majority of patients with early-stage mycosis fungoides (MF) have an excellent prognosis, a few cases progress to secondary Sezary syndrome (sSS), which carries a dismal clinical outcome. We retrospectively analyzed 135 cases of MF/SS and correlated molecular detection of T-cell clones in the skin and blood with other clinicopathologic findings. When stratified by the diagnoses, patients with MF demonstrated a 26.5% (31/117) positive rate for a blood T-cell clone, of which 50% (10/20) had an identical T-cell clone in the skin. Follow-up evaluation showed conversion into sSS or leukemic phase in 50% (5/10) of cases with a positive blood T-cell clone (estimated mean interval 41.8 months) in comparison to no cases in the group without a clone (0/31). Interestingly, 4/5 cases of sSS had an identical T-cell clone in the skin, while the remaining case did not have the test performed on skin for clonal comparison. Kaplan–Meier survival analysis demonstrated a poor clinical outcome in the group with a blood T-cell clone, in comparison with the group without, in overall survival (p < 0.0001) and progression-free survival (p < 0.0001; HR = 22.6). These findings suggest that molecular detection of a blood T-cell clone may have a role in predicting sSS. Due to amplification of non-neoplastic T-cell expansion in a significant number of cases, comparison of blood T-cell clones with skin may have confirmatory value.

Keywords::

• Mycosis fungoides
• secondary Sezary syndrome
• blood T-cell clone
• clinical outcome

Acknowledgements

We thank Steven R. Conlon in the Department of Pathology at Duke University Medical Center for his technical assistance with the images and figures, William G. Reese IV for his technical assistance with the T-cell clonality assay and Felisa Alcancia for her help with the flow cytometric data analysis.

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