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Updated: May 29, 2026
Isolating Human Peripheral Blood Mononuclear Cells and CD4+ T cells from Sézary Syndrome Patients for Transcriptomic Profiling
Published on: October 14, 2021
Functional and phenotypical alterations of polymorphonuclear cells in Sézary syndrome patients
Maria Teresa Fierro1, Anna Maria Cuffini, Mauro Novelli
1Department of Dermatology, Biomedical Sciences and Human Oncology, Turin University, Via Cherasco 23, 10126 Turin, Italy.
Abstract:
Sézary syndrome (SS), the leukemic variant of cutaneous T-cell lymphoma (CTCL), has a poor prognosis and infections represent the most frequent cause of death. Polymorphonucleate granulocytes (PMNs) constitute an essential part of the innate immune system: their phagocytic and killing activity against pathogens is mediated by the interactions between Toll-like receptors (TLRs) and the Pathogen-associated molecular patterns (PAMPs). The aim of this study was to investigate PMN functional activity and phenotype in SS patients and their correlation with the onset of infectious complications. This prospective study enrolled 18 consecutive SS patients; PMN functional activity was evaluated by phagocytosis and intracellular killing tests towards Klebsiella pneumoniae. Flow-cytometry was applied to analyze PMN phenotype. PMNs from SS patients displayed a reduced phagocytic activity and intracellular killing against K. pneumoniae at 30 min and 60 min, more pronounced in SS patients with recurrent infections. CD11b and CD66b median fluorescence intensity (MFI) was significantly higher in SS than in healthy subjects, whereas CD62L MFI was decreased. No significant differences in TLR2, 4, 8 and 9 percentage expression or MFI were found. An increased TLR5 percentage expression was documented. The impairment in PMN functional activities in SS could favour the immune-suppression and raise infection risk.
Insights
Sézary syndrome patients show impaired polymorphonucleate granulocyte (PMN) function, leading to increased infection risk. This study highlights reduced PMN phagocytosis and killing activity in Sézary syndrome, correlating with recurrent infections.
Area of Science:
- Immunology
- Hematology
- Dermatology
Background:
- Sézary syndrome (SS), a leukemic form of cutaneous T-cell lymphoma (CTCL), is associated with poor prognosis, with infections being the primary cause of mortality.
- Polymorphonucleate granulocytes (PMNs) are crucial for innate immunity, combating pathogens via phagocytosis and killing, processes influenced by Toll-like receptor (TLR) and Pathogen-associated molecular pattern (PAMP) interactions.
Purpose of the Study:
- To investigate the functional activity and phenotype of PMNs in SS patients.
- To determine the correlation between PMN function and the incidence of infectious complications in SS.
Main Methods:
- A prospective study involving 18 SS patients.
- Evaluation of PMN phagocytic and intracellular killing activity against Klebsiella pneumoniae.
- Flow cytometry analysis of PMN phenotype, including expression of CD11b, CD66b, CD62L, and TLRs (TLR2, 4, 5, 8, 9).
Main Results:
- SS patients exhibited significantly reduced PMN phagocytic and intracellular killing activity against K. pneumoniae compared to healthy controls.
- This functional impairment was more pronounced in SS patients experiencing recurrent infections.
- PMN phenotype analysis revealed increased CD11b and CD66b expression and decreased CD62L expression in SS patients. TLR5 expression was elevated, while TLR2, 4, 8, and 9 expression showed no significant differences.
- The observed impairment in PMN function in SS patients may contribute to immune suppression and increased susceptibility to infections.
Conclusions:
- PMN functional impairment, including reduced phagocytosis and killing capacity, is a significant characteristic of Sézary syndrome.
- Altered PMN phenotype and increased TLR5 expression are observed in SS patients.
- These PMN defects likely contribute to the heightened risk of infections and poor outcomes in Sézary syndrome, underscoring the need for targeted immune support strategies.
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