1. Cushing syndrome and glucocorticoids: T-cell lymphopenia, apoptosis, and rescue by IL-21.
- Author
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Hwang, SuJin, Tatsi, Christina, Kuehn, Hye, Niemela, Julie, Stoddard, Jennifer, Su, Yan, Lodish, Maya, Uzel, Gulbu, Spolski, Rosanne, Leonard, Warren, Holland, Steven, Fleisher, Thomas, Stratakis, Constantine, and Rosenzweig, Sergio
- Subjects
BCL2 ,NF-κB ,PI3K ,cytokines ,infections ,interleukins ,Adolescent ,Apoptosis ,Child ,Cushing Syndrome ,Cytokines ,Female ,Glucocorticoids ,Humans ,Leukocyte Count ,Lymphopenia ,Male ,T-Lymphocytes - Abstract
BACKGROUND: Pediatric endogenous Cushing syndrome (eCs) is mainly caused by pituitary corticotropin-producing adenomas, and most glucocorticoid-dependent effects progressively regress upon tumor removal. eCs reproduces long-term, high-dose glucocorticoid therapy, representing a clean, natural, and unbiased model in which to study glucocorticoid bona fide effects on immunity. OBJECTIVE: We performed extensive immunologic studies in otherwise healthy pediatric patients with eCs before and 6 to 13 months after tumor resection, as well as in in vitro glucocorticoid-treated control cells. METHODS: Flow cytometry, immunoblotting, enzyme-linked immunosorbent assay, real-time quantitative PCR, and RNA-Seq techniques were used to characterize patients and in vitro glucocorticoid treated cells. RESULTS: Reduced thymic output, decreased naive T cells, diminished proliferation, and increased T-cell apoptosis were detected before surgery; all these defects eventually normalized after tumor removal in patients. In vitro studies also showed increased T-cell apoptosis, with correspondingly diminished NF-κB signaling and IL-21 levels. In this setting, IL-21 addition upregulated antiapoptotic BCL2 expression and rescued T-cell apoptosis in a PI3K pathway-dependent manner. Similar and reproducible findings were confirmed in eCs patient cells as well. CONCLUSIONS: We identified decreased thymic output and lymphocyte proliferation, together with increased apoptosis, as the underlying causes to T-cell lymphopenia in eCs patients. IL-21 was decreased in both natural and in vitro long-term, high-dose glucocorticoid environments, and in vitro addition of IL-21 counteracted the proapoptotic effects of glucocorticoid therapy. Thus, our results suggest that administration of IL-21 in patients receiving long-term, high-dose glucocorticoid therapy may contribute to ameliorate lymphopenia and the complications associated to it.
- Published
- 2022