Pediatric medulloblastoma express immune checkpoint B7-H3

Purpose Medulloblastomas (MB) are highly malignant brain tumors that predominantly occur in young infants. Immunotherapy to boost the immune system is emerging as a novel promising approach, but is often hampered by inhibitory immune checkpoints. In the present study, we have studied immune checkpoint B7-H3 expression in a tissue cohort of human pediatric MB. Methods Expression of B7-H3 was detected by immunohistochemistry and classified via B7-H3 staining intensity and percentage of B7-H3 positive tumor cells. Subsequently, B7-H3 protein expression was distinguished in MB molecular subtypes and correlated to immune cell infiltrates, patient characteristics, and survival. Results B7-H3 protein expression was found in 23 out of 24 (96%) human pediatric MB cases and in 17 out of 24 (71%) MB cases > 25% of tumor cells had any level of B7-H3 expression. B7-H3 protein expression was more frequent on Group-4 MB as compared with other molecular subtypes (p = 0.02). Tumors with high B7-H3 expression showed less influx of γδT cells (p = 0.002) and CD3+ T cells (p = 0.041). Conclusion Immune checkpoint B7-H3 is differentially expressed by the large majority of pediatric MB. This further warrants the development of novel B7-H3-directed (immuno)therapeutic methods for children with incurable, metastatic, or chemo-resistant MB.

Impairment of antigen-presenting function of peripheral γδ T cells in patients with sepsis

Impairment of antigen-presenting functions is a key mechanism contributing to sepsis-induced immunosuppression. Recently, γδ T cells have been demonstrated as professional antigen-presenting cells (APCs); however, their role in sepsis remains unknown. In this in vitro study, the APC function of human peripheral γδ T cells was assessed using samples collected from 42 patients with sepsis and 27 age-matched healthy controls. The APC-related markers HLA-DR, CD27, CD80, and CCR7 on fresh γδ T cells were significantly higher in patients with sepsis compared with matched controls; however, they responded poorly to 4-hydroxy-3-methyl-2-butenyl pyrophosphate (HMBPP) stimulation, characterised by the deactivation of these APC markers and impaired proliferation. Furthermore, the adhesion function of γδ T cells, essential for antigen presentation, was greatly reduced in patients with sepsis; for instance, in co-cultures with green fluorescent protein-expressing Escherichia coli, HMBPP-activated γδT cells from healthy individuals adhered to E. coli efficiently, whereas no such phenomenon was observed with respect to γδT cells from patients with sepsis. In line with these results, in co-cultures with isolated CD4 + αβ T cells, HMBPP-activated γδT cells of healthy individuals promoted the efficient proliferation of CD4 + αβ T cells, whereas γδT cells from patients with sepsis did not do so. In conclusion, our findings show that the antigen-presenting function of γδ T cells is severely impaired in patients with sepsis and the mechanisms behind need further study.

Activation of T-bet, FOXP3, and EOMES in Target Organs From Piglets Infected With the Virulent PRRSV-1 Lena Strain

Transcription factors (TFs) modulate genes involved in cell-type-specific proliferative and migratory properties, metabolic features, and effector functions. Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogen agents in the porcine industry; however, TFs have been poorly studied during the course of this disease. Therefore, we aimed to evaluate the expressions of the TFs T-bet, GATA3, FOXP3, and Eomesodermin (EOMES) in target organs (the lung, tracheobronchial lymph node, and thymus) and those of different effector cytokines (IFNG, TNFA, and IL10) and the Fas ligand (FASL) during the early phase of infection with PRRSV-1 strains of different virulence. Target organs from mock-, virulent Lena-, and low virulent 3249-infected animals humanely euthanized at 1, 3, 6, 8, and 13 days post-infection (dpi) were collected to analyze the PRRSV viral load, histopathological lesions, and relative quantification through reverse transcription quantitative PCR (RT-qPCR) of the TFs and cytokines. Animals belonging to both infected groups, but mainly those infected with the virulent Lena strain, showed upregulation of the TFs T-bet, EOMES, and FOXP3, together with an increase of the cytokine IFN-γ in target organs at the end of the study (approximately 2 weeks post-infection). These results are suggestive of a stronger polarization to Th1 cells and regulatory T cells (Tregs), but also CD4+ cytotoxic T lymphocytes (CTLs), effector CD8+ T cells, and γδT cells in virulent PRRSV-1-infected animals; however, their biological functionality should be the object of further studies.

CD3+T, CD4+T, CD8+T, and CD4+T/CD8+T Ratio and Quantity of γδT Cells in Peripheral Blood of HIV-Infected/AIDS Patients and Its Clinical Significance

Objective. To investigate the quantity of CD4+T, CD4+T, CD8+T, and γδT cells in peripheral blood of HIV-infected/AIDS patients as well as to explore the possible role of CD4/CD8 ratio and γδT cells in the progression of HIV/AIDS, aimed at providing evidence for the diagnosis and treatment of AIDS. Methods. The quantity levels of CD3+T cells, CD4+T cells, CD8+T cells, and γδT cells in peripheral blood of 46 HIV-infected/AIDS patients and 30 healthy controls were detected by using flow cytometry. Results. The count of CD3+T, CD4+T, CD8+T, and γδT cells ( x ¯ ± s , A/μl) in the peripheral blood was 1183.64 ± 132.58 , 278.39 ± 122.38 , 863.13 ± 82.38 , and 22.53 ± 1.74 in the experimental group as well as 1456.46 ± 124.37 , 788.74 ± 189.67 , 569.61 ± 46.49 , and 10.96 ± 0.28 in the control group, respectively. The p values of the two groups were <0.005 after the t -test, revealing a statistically significant difference. The proportion of CD3+T, CD4+T, CD8+T, and γδT cells in total lymphocytes in the two groups ( x ¯ ± s , %) was 71.83 ± 5.37 , 13.39 ± 2.23 , 62.93 ± 5.81 , and 3.67 ± 0.87 in the experimental group, respectively. In the control group, the values were expressed as 66.72 ± 5.48 , 42.77 ± 3.38 , 31.41 ± 3.62 , and 1.73 ± 0.36 , respectively. After performing the t -test, p values in the two groups were <0.005 except CD3+T, with statistically significant differences. Besides, CD4/CD8 was 0.33 ± 0.11 in the experimental group and 1.48 ± 0.29 in the control group, t = 26.528 , p < 0.001 , exhibiting a significant statistical difference. Conclusion. HIV infection induces the activation and proliferation of CD8+T and γδT cells, contributing to the decrease of CD4+T cells, while CD8+T and γδT cells are involved in the immune response and tissue damage after HIV infection.

Identification of Immune-Related Key Genes in Ovarian Cancer Based on WGCNA

Background: Ovarian cancer (OV) is a fatal gynecologic malignancy and has poor survival rate in women over the age of forty. In our study, we aimed to identify genes related to immune microenvironment regulations and explore genes associated with OV prognosis.Methods: The RNA-seq data of GDC TCGA Ovarian Cancer cohort of 376 patients was retrieved from website. Weighted gene co-expression network analysis (WGCNA) and ESTIMATE algorithm were applied to identify the key genes associated with the immune scores. The correlation between key genes and 22 immune cell types were estimated by using CIBERSORT algorithms.Results: WGCNA showed that the pink module was most correlated with the immune score. Seven of 14 key genes (FCRL3, IFNG, KCNA3, LY9, PLA2G2D, THEMIS, and TRAT1) were significantly associated with the OS of OV patients. Correlation analysis showed our key genes positively related to M1 macrophages, CD8 T cells, plasma cells, regulatory T (Treg) cells and activated memory CD4 T cells, and negatively related to naive CD4 T cells, M0 macrophages, activated dendritic cells (DCs) and memory B cells. Kaplan-Meier survival analysis showed that lower abundances of neutrophils and higher abundances of M1 macrophages, plasma cells, T cells gamma delta (γδT) cells and follicular helper T (Tfh) cells predicted better OV prognosis.Conclusion: Forteen key genes related to the immune infiltrating of OV were identified, and seven of them were significantly related to prognosis. These key genes have potential roles in tumor infiltrating immune cells differentiation and proliferation. This study provided potential prognostic markers and immunotherapy targets for OV.

Comparison of and Immune Reconstitution and Graft Versus Host Disease in 30mg/Kg Anti-T-Lymphocyte Globuline with 60mg/Kg ATLG As Graft Versus Host Disease Prophylaxis in Matched Unrelated Donor Myeloablative Peripheral Blood Stem Cell Transplantation

Introduction: Data on the influence of different ATLG doses on immune reconstitution (IR) and GvHD in MUD allo-SCT is limited. In this study, we compared the impact of ATLG doses (30mg/kg vs 60 mg/kg) on IR and transplant outcomes. Methods: In this retrospective study we included 289 patients who received MUD allografts (HLA 10/10) between 2005-2019 in the University Cance Center University of Hamburg. All patients received PBSC-allo-SCT with MAC for various hematological malignancies. Seventy-three patients received 30mg/kg ATLG, and 216 patients received 60mg/kg (on days -3.-2 and -1) prior to allo-SCT. Periphereal blood samples were collected on days +30, +100 and +180 and analyzed by flow cytometry for following lymphocyte populations: T-cells (total and activated), T-helper cells (total, naïve and memory), cytotoxic T-cells (total, naïve and memory), B-Lymphocytes (total, naïve and memory), NK-cells, NKT-cells, γδT-cells and regulatory T-cells. Results: Neutrophil and platelet engraftments were significantly delayed after the 60mg/kg compared to 30mg/kg group with medians of 11 days (range, 8-23) vs 12 days (8-27) (p=0.009) for neutrophil and 14 days (range, 9-53) vs 16 days (range, 8-237) for platelets, respectively (p=0.002). We observed a higher incidence of EBV reactivation within the first 100 days in the 60mg/kg group (41% vs 21% in the 30mg/kg group, p=0.049). Higher cumulative incidence of Infections Day +100 was observed in the 60 mg/Kg group with an incidence of 75% vs that of 67% in the 30mg/Kg group respectively (p=0.002). At day +30 we observed a faster reconstitution of naïve-B cells (p&lt;0.0001) and γδ T cells (p=0.045) in the 30mg/kg group. No significant differences in IR were observed at day +100. At day +180 the use of 30mg/Kg was associated with a faster naïve helper T-cell (p=0.046), NK-cells (p=0.035), and naïve B-cell reconstitution (p=0.009). The incidence of aGVHD grade II-IV was comparable between the groups: 63% and 59% in the 30mg/Kg and 60mg/Kg groups, respectively. We observed a higher incidence of grade IV aGvHD in the 30mg/kg group (8%) comparing with the rate of 0.5% in the 60mg/kg group (p=0.0002), this was confirmed in multivariate analysis: RR 0.65 (95%CI 0.005-0.363) p= 0.004. After a median follow up of 21 months (range, 1-161) there were no significant differences in OS, PFS, NRM, RI and cGVHD between the groups. Conclusion: The choice of ATLG dose has significant impact on IR after MUD-allo-SCT. Higher doses are associated with reduced severe aGVHD, however at the cost of delaying engraftment and increasing infections. Disclosures Ayuk: Celgene/BMS: Honoraria; Gilead: Honoraria; Janssen: Honoraria; Mallinckrodt/Therakos: Honoraria, Research Funding; Miltenyi Biomedicine: Honoraria; Novartis: Honoraria; Takeda: Honoraria.

Activated naïve γδ T cells accelerate deep molecular response to BCR-ABL inhibitors in patients with chronic myeloid leukemia

Tyrosine kinase inhibitors (TKIs) that target BCR-ABL are the frontline treatments in chronic myeloid leukemia (CML). Growing evidence has shown that TKIs also enhance immunity. Since gamma-delta T (γδT) cells possess the potent anticancer capability, here we investigated the potential involvement of γδT cells in TKI treatments for CML. We characterized γδT cells isolated from chronic-phase CML patients before and during TKI treatments. γδT expression increased significantly in CML patients who achieved major molecular response (MMR) and deep molecular response (DMR). Their Vδ2 subset of γδT also expanded, and increased expression of activating molecules, namely IFN-γ, perforin, and CD107a, as well as γδT cytotoxicity. Mechanistically, TKIs augmented the efflux of isopentenyl pyrophosphate (IPP) from CML cells, which stimulated IFN-γ production and γδT expansion. Notably, the size of the IFN-γ+ naïve γδT population in TKI-treated CML patients was strongly correlated with their rates to reach DMR and with the duration on DMR. Statistical analysis suggests that a cutoff of 7.5% IFN-γ+ naïve subpopulation of γδT in CML patients could serve as a determinant for MR4.0 sustainability. Our results highlight γδT cells as a positive regulator for TKI responses in CML patients.