The decreased expression of CD3 zeta chains in cancer patients is not reversed by IL-2 administration
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F Farace1, E Angevin, J Vanderplancke
1Unité d'Immunologie Cellulaire, INSERM U333, Villejuif, France.
Abstract:
The mechanisms underlying the impaired immune response frequently observed in cancer patients are poorly understood. Recently, a decreased expression of the signal-transducing CD3 zeta chains has been shown to occur in patients with colorectal or renal-cell carcinoma. Here, we have investigated the expression of the zeta molecule on lymphocytes from patients with advanced cancers including renal-cell carcinoma (n = 21), hepatic colorectal carcinoma metastases (n = 6), head-and-neck squamous-cell carcinoma (n = 7) or miscellaneous tumors (n = 7), using flow cytometry analysis of PBMCs with monoclonal antibody specific for the cytoplasmic domain of the zeta chain. The same analysis was also performed with patients undergoing IL-2 therapy (from 5 days up to 3 months i.v. or s.c.). PBMCs from patients (n = 41) showed a significant decrease in expression of the zeta chains as compared to the levels found in lymphocytes from healthy controls (n = 15), which was not reversed by IL-2 administration. Together, these results suggest that an alteration in the expression of the zeta-chain-transducing element in PBMCs may be a common cause of progressive immunosuppression in advanced cancer patients and that IL-2 is not sufficient to reverse this situation in vivo.
Insights
Cancer patients often have weakened immune systems due to decreased CD3 zeta chain expression on lymphocytes. This reduction in zeta chains, crucial for immune signaling, was observed across various advanced cancers and was not improved by IL-2 therapy.
Area of Science:
- Immunology
- Oncology
- Molecular Biology
Background:
- Impaired immune responses are common in cancer patients, but underlying mechanisms remain unclear.
- Decreased expression of CD3 zeta chains, a key signal transducer, has been noted in specific cancers.
Purpose of the Study:
- To investigate zeta molecule expression on lymphocytes in patients with advanced cancers.
- To determine if Interleukin-2 (IL-2) therapy can reverse alterations in zeta chain expression.
Main Methods:
- Flow cytometry was used to analyze peripheral blood mononuclear cells (PBMCs) from cancer patients and healthy controls.
- Monoclonal antibodies specific for the cytoplasmic domain of the zeta chain were employed.
- Analysis included patients with renal-cell carcinoma, colorectal carcinoma metastases, head-and-neck squamous-cell carcinoma, and miscellaneous tumors, as well as those undergoing IL-2 therapy.
Main Results:
- Patients with advanced cancers exhibited significantly decreased expression of zeta chains on PBMCs compared to healthy controls.
- This decrease in zeta chain expression was a common finding across different types of advanced cancers studied.
- IL-2 therapy, administered intravenously or subcutaneously for up to three months, did not restore normal zeta chain expression levels in vivo.
Conclusions:
- Altered expression of the zeta-chain-transducing element in PBMCs may be a significant factor contributing to progressive immunosuppression in advanced cancer.
- Interleukin-2 therapy alone is insufficient to reverse the observed reduction in zeta chain expression in these patients.