Objective. Rapid restoration of corneal epithelium integrity after injury is particularly important for preserving corneal transparency and vision. Mesenchymal stem cells (MSCs) can be taken into account as the promising regenerative therapeutics for improvement of wound healing processes based on the variety of the effective components. The extracellular vesicles form MSCs, especially exosomes, have been considered as important paracrine mediators though transferring microRNAs into recipient cell. This study investigated the mechanism of human umbilical cord MSC-derived small extracellular vesicles (HUMSC-sEVs) on corneal epithelial wound healing. Methods. HUMSC-sEVs were identified by transmission electron microscopy, nanoparticle tracking analysis, and Western blot. Corneal fluorescein staining and histological staining were evaluated in a corneal mechanical wound model. Changes in HCEC proliferation after HUMSC-sEVs or miR-21 mimic treatment were evaluated by CCK-8 and EdU assays, while migration was assessed by in vitro scratch wound assay. Full-length transcriptome sequencing was performed to identify the differentially expressed genes associated with HUMSC-sEVs treatment, followed by validation via real-time PCR and Western blot. Results. The sEVs derived from HUMSCs can significantly promote corneal epithelial cell proliferation, migration in vitro, and corneal epithelial wound healing in vivo. Similar effects were obtained after miR-21 transfection, while the beneficial effects of HUMSC-sEVs were partially negated by miR-21 knockdown. Results also show that the benefits are associated with decreased PTEN level and activated the PI3K/Akt signaling pathway in HCECs. Conclusion. HUMSC-sEVs could enhance the recovery of corneal epithelial wounds though restraining PTEN by transferring miR-21 and may represent a promising novel therapeutic agent for corneal wound repair.

This study aimed to evaluate treatment response, survival, safety profiles, and predictive factors to chimeric antigen receptor T cell (CAR-T) therapy in Chinese patients with relapsed or refractory B cell acute lymphoblast leukemia (R/R B-ALL). 39R/R B-ALL patients who underwent CAR-T therapy were included. Baseline data were collected from patients’ electronic medical records. Patients’ peripheral bloods, bone marrow aspirates, and biopsies were obtained for routine examination, and treatment response and survival profiles as well as adverse events were evaluated. The rates of complete remission (CR), CR with minimal residual disease (MRD) negative/positive, and bridging to hematopoietic stem-cell transplantation (HSCT) were 92.3%, 76.9%, 15.4%, and 43.6%, respectively. The median event-free survival (EFS) was 11.6 months (95% confidence interval (CI): 4.0–19.2 months) and median overall survival (OS) was 14.0 months (95% CI: 10.9–17.1 months). Bridging to HSCT independently predicted better EFS and OS, while high bone marrow blasts level independently predicted worse EFS. The incidence of cytokine release syndrome (CRS) was 97.4%, and refractory disease as well as decreased white blood cell independently predicted higher risk of severe CRS. Other common adverse events included hematologic toxicities (grade I: 5.1%, grade II: 7.7%, grade III: 17.9%, grade IV: 69.2%), neurotoxicity (28.2%), infection (38.5%), and admission for intensive care unit (10.3%). In conclusion, CAR-T therapy presents with promising treatment response, survival and safety profiles, and higher disease burden predicts worse survival as well as increased risk of severe CRS in Chinese R/R B-ALL patients.

Purpose: Assessing the possibility of finding tumor-infiltrating lymphocytes (TIL) in bone marrow of acute myeloid leukemia (AML) patients and evaluating the anti-tumor activity of these TIL against autologous AML cells. Patients and methods: TIL were immunomagnetically isolated by using anti-CD3 from bone marrow samples of 20 patients at the presentation of AML or four weeks upon completion of chemotherapy. TIL were ex vivo expanded for two weeks and immunophenotyped. Functionality in terms of cytokine secretion and cytotoxicity was assessed by γ-interferon quantitation and Elispot assay, respectively. Results: TIL were detected in bone marrow samples of 50% (10/20) of the patient cohort. They were noted to highly express CD137 and PD-1 and display a significantly higher anti-tumor reactivity compared to that of autologous peripheral blood lymphocytes. TIL could be expanded in co-cultures with irradiated feeder cells supplemented with interleukin (IL)-7 and IL-15. Conclusion: Data suggested the presence of reactive γ-interferon-secreting TIL in AML patients. They are expandable and possess anti-tumor activity, which might have a great potential in the development of adoptive cellular therapy for AML.

Natural Killer (NK) cells have shown promising prospects in ‘off‐the‐shelf’ cell therapy, particularly the NK‐92 cell line, which can serve as a foundation for the next generation of universal chimeric antigen receptor (CAR)‐engineered NK products. A key strategy for generating universal cellular products is the elimination of the beta‐2‐microglobulin (B2M) gene, which encodes a component of MHC class I molecules (MHC‐I) that plays a role in the presentation of foreign antigens and in the ‘licensing’ or ‘education’ of NK cells. To functionally study the impacts of MHC‐I deficiency on NK‐92, we generated a B2M knockout (KO) NK‐92MI (B‐92) cell line and compared the multidimensional properties of B2M KO and wild‐type NK‐92MI cells in terms of biological phenotypes, effector functions, and transcriptomic signatures. We observed a decrease in activating receptors, cytokine production, and cytotoxicity in B‐92 cells. Further analysis of signalling events revealed that the upregulated expression and phosphorylation of SHP‐1 in B‐92 cells inhibited the phosphorylation levels of STAT3 and ERK, thereby affecting their killing function. By knocking out SHP‐1 (PTPN6), we partially restored the cytotoxic function of B‐92 cells. Notably, we also found that CAR modification can overcome the hyporesponsiveness of B‐92 cells. These findings will facilitate further exploration in the development of NK cell‐based products.