PD-1 expression, mRNA level and cytotoxicity changes in CD19CAR-T cells / 中华血液学杂志

Objective: To observe the changes of PD-1 expression, mRNA level and cytotoxic activity of CD19 CAR-T cells during the culture process of CAR-T cells. Methods: The peripheral blood T cells of 6 lymphoma patients with high expression of PD-1 and 6 healthy volunteers were the source of CAR-T cells. The expression of PD-1 was analyzed by flow cytometry. The mRNA level of PD-1 was analyzed by PCR. The cell proliferation was analyzed by CCK-8 assay. The cytotoxicity was analyzed by LDH assay. Results: ①The transfection efficiency of high PD-1 expression T cells and healthy volunteer T cells were as the same (P>0.05) . ②The cell proliferation capacity of CD19 CAR-T cells from high PD-1 expression T cells or healthy volunteer T cells, with or without PD-1 inhibitor were as the same (P>0.05) . ③The cytotoxicity to lymphoma cells of high PD-1 expression T cells and CAR-T cells were lower than that of these two T cells combined with PD-1 inhibitor and the CAR-T cells from healthy volunteer T cells (P<0.001) . There was no difference of the cytotoxicity between the CAR-T cells from high PD-1 expression T cells combined with PD-1 inhibitor and the CAR-T cells from healthy volunteer (P>0.05) . ④There was no difference of the expression of PD-1 in all CAR-T cell groups during the culture process (P>0.05) . There was no difference of mRNA level of PD-1 in all groups during the culture process (P>0.05) . ⑤The PD-1 expression of CAR-T cells increased by the time of culture after contacting with lymphoma cells (P<0.001) . The PD-1 inhibitors could antagonize this effect. There was no difference of mRNA level of PD-1 in all groups after contacting with lymphoma cells (P>0.05) . Conclusion: The PD-1 expression of CAR-T cells from high PD-1 expression T cells increased by the time of culture after contacting with lymphoma cells. However, the mRNA level of PD-1 of all groups did not change, even if PD-1 inhibitor was applied.

Efficacy and safety of CD19 chimeric antigen receptor T cells for the treatment of 22 patients with B-cell lymphoma / 中华血液学杂志

Objective: To investigate the efficacy and safety of CD19 chimeric antigen receptor T (CAR-T) lymphocytes for the treatment of B cell lymphoma. Methods: A total of 22 patients with B-cell lymphoma from February 1, 2017 to July 1, 2018 were reviewed to evaluate the efficacy and adverse reactions of CD19 CAR-T. Results: Of 22 patients with B-cell lymphoma received CD19 CAR-T cells, the median dose of CAR-T cells was 7.2 (2.0-12.0) ×106/kg. Nine of 12 cases of relapse refractory patients were overall response. Complete remission (CR) occurred in 2 of 12 patients, partial remission (PR) in 7 of 12 patients. The overall response in minor residual disease positive (MRD) group was 8 of 10 patients. CD19 CAR-T cells proliferated in vivo and were detectable in the blood of patients. The peak timepoints of CAR-T cells proliferated in the relapsed refractory and MRD positive groups were 12 (5-19) and 4.5 (1-12) days after treatment respectively, and among peripheral blood cells, CAR-T cells accounted for 10.10% (3.55%-24.74%) and 4.02% (2.23%-28.60%) of T lymphocytes respectively. The MRD positive patients achieved sustained remissions during a median follow-up of 8 months (rang 3-18 months) . None of all the patients relapsed during a median follow-up time of 10 months (3-18 months) . However, 7 PR responders of the relapsed refractory patients maintained a good condition for 1.5-6.0 months. One patient bridged to hematopoietic stem cell transplantation, another one sustained remission for 12 months. Cytokine-release syndrome (CRS) occurred in 14 patients with grade 1-2 CRS in MRD positive group and grade 3 CRS in relapsed refractory group. Conclusions: CAR-T cell therapy not only played a role in the rescue treatment of relapsed and refractory patients, but also produced a surprising effect in the consolidation and maintenance of B-cell lymphoma. CD19 CAR-T cells might be more effective in the treatment of MRD positive B-cell lymphoma patients than in the refractory or relapsed cases. High response rate was observed with fewer adverse reactions.

Effect of PD-1 inhibitor Nivolumab on the proliferation and cytotoxicity of anti-CD19 chimeric antigen receptor T cells / 中华血液学杂志

Objective: To Evaluation the effect of PD-1 inhibitor Nivolumab on the proliferation and cytotoxicity of anti-CD19 chimeric antigen receptor T cells (CD19-CAR-T) in vitro. Methods: Five patients with high PD-1 expression in peripheral blood and five healthy volunteers were selected. These peripheral blood mononuclear cells were used as the source of T cells to prepare CD19-CAR-T cells. Different doses (72, 36, 18 μg/ml) of Nivolumab was added on day 8 to the culture medium. Patient T cells incubated with 72 μg/ml Nivolumab and CD19-CAR-T cells of healthy volunteers were used as controls. CCK-8, lactate dehydrogenase (LDH) cytotoxicity assay and ELASA were used to detect the proliferation capacity, the specific cytotoxicity and the inflammatory factor secretion. Results: ①T cells from patients with high expression of PD-1 as the source of CD19-CAR-T cells did not affect transfection rate compared with that of healthy volunteers [(32.80±7.22)% vs (35.10±5.84)%, t=-0.554, P=0.593]. ②Incubation of CD19-CAR-T cells with 72 μg/ml Nivolumab did not affect CD19-CAR-T cell proliferation, but its cytotoxicity was significantly higher than that of CD19-CAR-T cells alone or patients' T cells +72 μg/ml Nivolumab (all P<0.001), there was no significant difference in the killing activity between the 72 μg/ml and 36 μg/ml Nivolumab treated CD19-CAR-T cells on Pfeiffer cells (P=0.281, 0.267, respectively), and they were all higher than those of 18 μg/ml Nivolumab treated CD19-CAR-T cells (all P<0.001). ③Different doses of PD-1 inhibitor Nivolumab combined with CD19-CAR-T cells does not affect the secretion of IFN-γ and IFN-α (all P>0.05). Conclusion: Combination of 36 μg/ml PD-1 inhibitor and CD19-CAR-T cells could reduce the drug toxicity and enhance the cytotoxicity.

Expression and Significance of HIF-1α in Erythropoiesis of Secondary Iron Overload Disease after Irradiation Damage / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To study the expression of hypoxia inducible factor 1α(HIF-1α) of iron-overloaded in irradiated mice and its effect on erythropoiesis.</p><p><b>METHODS</b>Twenty mice were randomly divided into 4 groups: Ctrl (control group), IR (irradiation group), IO (irradiation + iron overload group), and RAPA (rapamycin treatment group). The iron overload model was verified. The CFU-E (colony forming unit-erythroid) and BFU-E(burst colony forming unit-erythroid) were cultured; flow cytometry was used to detect the ratios of early stage (Ter119CD71) to late stage (Ter119CD71) of primitive erythroblasts; RT-PCR was used to detect the mRNA expression of HIF-1α and its related signal molecules in bone marrow cells.</p><p><b>RESULTS</b>The expression of HIF-1α in IR and IO group was significantly higher than that in Ctrl group, and that in IO group was significantly higher than IR group (P<0.05). The ratio of late stage primitive erythroblasts, the number of CFU-E and BFU-E in both IR and IO group were lower than those in Ctrl group, and those in IO group were significantly lower than those in IR group (P<0.05). Compared with Ctrl group, the expression of HIF-1α related signal pathway molecules in both IR and IO group was significantly decreased (P<0.05). Compared with IO group, the expression of HIF-1α and its related signal molecules in RAPA(mTOR inhibitor) group was decreased significantly (P<0.05), the number of BFU-E was increased significantly(P<0.05).</p><p><b>CONCLUSION</b>Irradiation induces the increase of HIF-1α and the decrease of the ability of hematopoietic colony formation and the ratio of late stage primitive erythroblasts. Iron overload can aggravate the injury. mTOR inhibitor rapamycin can partially alleviate the injury, suggesting that iron overload can lead to injury of erythropoiesis through HIF-1α.</p>

Effects of Iron Overload on the Apoptosis and Function of Splenic CD8+ T Cells in Mice / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects of iron overload on apoptosis and function of splenic CD8+ T cells in mice.</p><p><b>METHODS</b>Forty C57BL/6 mice were randomly divided into control groups, Iron overload (IO), IO+NAC and IO+DFX groups. The iron overload model was established by intraperitoneal injection of iron dextran, and saline was injected as the control. The levels of intracellular reactive oxygen species (ROS) and labile iron pool (LIP) were analyzed by measuring the mean fluorescence intensity (MFI) of 2-7 dichlorofluorescein (DCF) or calcein. The ratio of CD8+ T cells and the levels of IFN-γ, TNF-α, Granzyme-B, and perforin in CD8+ T cells were detected by flow cytometry. The CD8+ T cell apoptosis was determined by flow cytometry with Annexin V/PI double staining. Real-time PCR was used to detect the expression of IFN-γ, TNF-α, Granzyme-B, perforin, BCL-2, and bax at mRNA level in CD8+ T cells.</p><p><b>RESULTS</b>Iron overload was found by spleen iron staining and flow cytometry. The level of intracellular ROS in iron overload (IO) groups was higher than that of the control groups (P<0.01). The percentage of CD8+ T cells in spleen from mice with IO was lower than that in control groups (P<0.05). The expression of IFN-γ and Granzyme-B in CD8+ T cells in IO group were lower than that in control group, the expression of IFN-γ and Granzyme-B at mRNA level in CD8+ T cells was lower than that of control group (P<0.05). CD8+ T cell apoptosis in iron overload group was significantly higher than that in control groups (P<0.01); the expression of BCL-2 at mRNA level was lower than that in control group, but the expression of BAX at mRNA level was higher than that in control group (P<0.05). These effects could be reversed after treating iron-overloaded mice with DFX or NAC.</p><p><b>CONCLUSION</b>Iron overload can inhibit the ratio of CD8+ T cells of splenic cells in mice, decrease the expression of IFN-γ, Granzyme-B, increase the apoptosis of CD3+ CD8+/CD8-. These effects may be regulated through increasing the intracellular ROS level, and can be partially reversed after treating iron-overloaded mice with DFX or NAC.</p>