αßγδ T cells play a vital role in fetal human skin development and immunity.

T cells in human skin play an important role in the immune defense against pathogens and tumors. T cells are present already in fetal skin, where little is known about their cellular phenotype and biological function. Using single-cell analyses, we identified a naive T cell population expressing αß and γδ T cell receptors (TCRs) that was enriched in fetal skin and intestine but not detected in other fetal organs and peripheral blood. TCR sequencing data revealed that double-positive (DP) αßγδ T cells displayed little overlap of CDR3 sequences with single-positive αß T cells. Gene signatures, cytokine profiles and in silico receptor-ligand interaction studies indicate their contribution to early skin development. DP αßγδ T cells were phosphoantigen responsive, suggesting their participation in the protection of the fetus against pathogens in intrauterine infections. Together, our analyses unveil a unique cutaneous T cell type within the native skin microenvironment and point to fundamental differences in the immune surveillance between fetal and adult human skin.

Adolescents and Young Adults (AYAs) With Initially Localized and Metastatic Bone Sarcomas: A Retrospective Single Center Analysis of Side Effect Management.

BACKGROUND/AIM: Ewing sarcoma (ES) and osteosarcomas (OSA) are the most common bone tumor types in adolescents and young adults (AYA). Therapy management of these tumors consists of preoperative chemotherapy, operation, and postoperative chemotherapy. The aim of this study was to evaluate the efficacy and tolerability of EURAMOS-A and EURO E.W.I.N.G. protocols. PATIENTS AND METHODS: We retrospectively evaluated 31 patients between 18 and 39 years of age with ES and OSA treated at the Department of Medicine I, Clinical Division of Oncology. Patients with ES were treated according the EURO E.W.I.N.G protocol, whereas patients with OSA according to the EURAMOS-1 protocol. RESULTS: Most frequent tumor sites for ES were thorax and pelvis, each 33%. Eight patients had initially localized disease (67%). A median of 3 cycles of full dose chemotherapy could be administered. Nine patients had a dose reduction (75%). Most common reason for dose reduction was prolonged aplasia (67%). Overall response rate (ORR) was 33%. For OSA patients, the most frequent tumor site was the lower extremity (58%). Sixteen patients (84%) had initially localized disease. A median of only 9 cycles of EURAMOS-1 in full dose could be administered. Most common reason for dose reduction was elevated methotrexate level (53%) and ORR was 90%. CONCLUSION: The two studied protocols were well-tolerated in the AYA patients included in this study. Dose reductions instead of dose delays should be considered when side effects occur.