Notch receptors signal through a highly conserved pathway to influence cell fate decisions. Notch1 is required for T lineage commitment; however, a role for Notch signaling has not been clearly defined for the peripheral T cell response. Notch gene expression is induced, and Notch1 is activated in primary CD4+ T cells following specific peptide-Ag stimulation. Notch activity contributes to the peripheral T cell response, as inhibition of endogenous Notch activation decreases the proliferation of activated T cells in a manner associated with the diminished production of IL-2 and the expression of the high affinity IL-2R (CD25). Conversely, forced expression of a constitutively active Notch1 in primary T cells results in increased surface expression of CD25, and renders these cells more sensitive to both cognate Ag and IL-2, as measured by cell division. These data suggest an important role for Notch signaling during CD4+ T cell responses, which operates through augmenting a positive feedback loop involving IL-2 and its high affinity receptor.
CD40 is a cell-surface molecule that critically regulates immune responses. CP-870,893 is a fully human, CD40-specific agonist monoclonal antibody (mAb) exerting clinical antineoplastic activity. Here, the safety of CP-870,893 combined with carboplatin and paclitaxel was assessed in a Phase I study. Patients with advanced solid tumors received standard doses of paclitaxel and carboplatin on day 1 followed by either 0.1 mg/Kg or 0.2 mg/Kg CP-870,893 on day 3 (Schedule A) or day 8 (Schedule B), repeated every 21 d. The primary objective was to determine safety and maximum-tolerated dose (MTD) of CP-870,893. Secondary objectives included the evaluation of antitumor responses, pharmacokinetics and immune modulation. Thirty-two patients were treated with CP-870,893, 16 patients on each schedule. Two dose-limiting toxicities were observed (grade 3 cytokine release and transient ischemic attack), each at the 0.2 mg/Kg dose level, which was estimated to be the MTD. The most common treatment-related adverse event was fatigue (81%). Of 30 evaluable patients, 6 (20%) exhibited partial responses constituting best responses as defined by RECIST. Following CP-870,893 infusion, the peripheral blood manifested an acute depletion of B cells associated with upregulation of immune co-stimulatory molecules. T-cell numbers did not change significantly from baseline, but transient tumor-specific T-cell responses were observed in a small number of evaluable patients. The CD40 agonist mAb CP-870,893, given on either of two schedules in combination with paclitaxel and carboplatin, was safe for patients affected with advanced solid tumors. Biological and clinical responses were observed, providing a rationale for Phase II studies.
Background & Aims Cholesteryl Ester Storage Disease, an inherited deficiency of lysosomal acid lipase, is an underappreciated cause of progressive liver disease with no approved therapy. Presenting features include dyslipidemia, elevated transaminases, and hepatomegaly. Methods To assess the clinical effects and safety of the recombinant human lysosomal acid lipase, sebelipase alfa, 9 patients received 4 once-weekly infusions (0.35, 1, or 3 mg·kg−1) in LAL-CL01 which is the first human study of this investigational agent. Patients completing LAL-CL01 were eligible to enroll in the extension study (LAL-CL04) in which they again received 4 once-weekly infusions of sebelipase alfa (0.35, 1, or 3 mg·kg−1) before transitioning to long term every other week infusions (1 or 3 mg·kg−1). Results Sebelipase alfa was well-tolerated with mostly mild adverse events unrelated sebelipase alfa. No anti-drug antibodies were detected. Transaminases decreased in patients in LAL-CL01 and increased between studies. In 7 patients receiving ongoing sebelipase alfa treatment in LAL-CL04, mean±SD decreases for alanine transaminase and aspartate aminotransferase at week 12 compared to the baseline values in LAL-CL01 were 46±21U/L (-52%) and 21±14U/L (-36%), respectively (p<0.05). Through week 12 of LAL-CL04, these 7 patients also showed mean decreases from baseline in total cholesterol of 44±41mg/dL (-22%; p=0.047), low density lipoprotein-cholesterol of 29±31mg/dL (-27%; p=0.078), and triglycerides of 50±38mg/dL (-28%, p=0.016) and increases in high density lipoprotein-cholesterol of 5mg/dL (15%; p=0.016). Conclusions These data establish that sebelipase alfa, an investigational enzyme replacement, in patients with Cholesteryl Ester Storage Disease is well tolerated, rapidly decreases serum transaminases and that these improvements are sustained with long term dosing and are accompanied by improvements in serum lipid profile.
Objectives: During the coronavirus-19 pandemic, experts recommended delaying routine cancer screening and modifying treatment strategies. We sought to understand the sequalae of these recommendations. Materials and Methods: We performed a retrospective single-center analysis of screening, diagnosis, and treatment of lung, colorectal, and breast cancer. Data was collected from our institutional cancer registry. Prepandemic (2016-2019) was compared with pandemic (2020) data. Results: Three thousand three sixty one screening chest computed tomography scans (CTs), 35,917 colonoscopies, and 48,093 screening mammograms were performed. There was no difference in CTs [81.0 (SEM10.0) vs. 65.6 (SEM3.29), P =0.067] or mammograms [1017.0 (SEM171.8) vs. 809.4 (SEM56.41), P =0.177] in 2020 versus prepandemic. There were fewer colonoscopies in 2020 [651.4 (SEM103.5) vs. 758.91 (SEM11.79), P =0.043]. There was a decrease in cancer diagnoses per month in 2020 of lung [22.70 (SEM1.469) vs. 28.75 (SEM0.8216), P =0.003] and breast [38.56 (SEM6.133) vs. 51.82 (SEM1.257), P =0.001], but not colorectal [13.11 (SEM1.467) vs. 15.88 (SEM0.585), P =0.074] cancer. There was no change in stage at presentation for lung ( P =0.717), breast ( P =0.115), or colorectal cancer ( P =0.180). Lung had a shorter time-to-treatment in 2020 [38.92 days (SEM 2.48) vs. 66 (SEM1.46), P =0.002]. Conclusions: In 2020, there was no difference in screening studies for lung and breast cancer but there was a decrease in new diagnoses. Although there were fewer colonoscopies performed in 2020, there was no change in new colorectal cancer diagnoses. Despite changes in guidelines during the pandemic, the time-to-treatment for lung cancer was shorter and was unchanged for colorectal and breast cancer. These findings highlight the importance of continuing care for a vulnerable patient population despite a pandemic.
T cells developing in the thymus are ultimately derived from bone marrow (BM) hematopoietic stem cells (HSCs). An understanding of the developmental steps between HSCs and T cells is important for gaining insight into cancers of the T lineage, improving T cell reconstitution after BM transplantation, and also to help ameliorate immunological defects in aging. In this article, we summarize our current understanding of the inter-related fields of early T cell development and thymic aging, and briefly discuss major unresolved questions in this field.
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