Relapse of aplastic anemia responsive to sirolimus combined with cyclosporine

Prolonged haematologic toxicity in CAR-T-cell therapy: A review

Chimeric antigen receptor-T-cell (CAR-T-cell) therapy is a novel immunotherapy with encouraging results for treatment of relapsed/refractory haematologic malignancies. With increasing use, our understanding of immune-mediated side effects such as cytokine release syndrome and neurotoxicity has improved; nevertheless, prolonged haematologic toxicity (PHT), with a high incidence rate, remains underrecognized. Owing to heterogeneity in populations, the CAR-T cells used and diseases treated as well as differences in the definition of PHT, its rate, risk factors and management vary across studies. In this review, we provide a narrative of PHT occurring in patients following CAR-T-cell therapy; evidence of PHT treatment strategies is also presented, with the aim of contributing to systematic understanding of PHT.

Impaired immunosuppressive role of myeloid-derived suppressor cells in acquired aplastic anemia

Myeloid-derived suppressor cells (MDSC) are a group of heterogeneous immature myeloid cells and display immunosuppressive function. In this study, MDSC populations were evaluated in acquired aplastic anemia (AA) (n=65) in which aberrant immune mechanisms contributed to bone marrow destruction. Our data demonstrate that both the proportion and immunosuppressive function of MDSC are impaired in AA patients. Decreased percentage of MDSC, especially monocytic MDSC, in the blood of AA patients (n=15) is positively correlated with the frequency of T-regulatory cells, bone marrow level of WT1 and decreased plasma level of arginase-1. RNA sequencing analyses reveal that multiple pathways including DNA damage, interleukin 4, apoptosis, and Jak kinase singnal transducer and activator of transcription are upregulated, whereas transcription, IL-6, IL-18, glycolysis, transforming growth factor and reactive oxygen species are downregulated in MDSC of AA (n=4), compared with that of healthy donors (n=3). These data suggest that AA MDSC are defective. Administration of rapamycin significantly increases the absolute number of MDSC and levels of intracellular enzymes, including arginase-1 and inducible nitric-oxide synthase. Moreover, rapamycin inhibits MDSC from differentiating into mature myeloid cells. These findings reveal that impaired MDSC are involved in the immunopathogenesis of AA. Pharmacologically targeting of MDSC by rapamycin might provide a promising therapeutic strategy for AA.

Case Report: Sirolimus Alleviates Persistent Cytopenia After CD19 CAR-T-Cell Therapy

Chimeric antigen receptor T (CAR-T) cells show good efficacy in the treatment of relapsed and refractory B-cell tumors, such as acute B-cell leukemia (ALL) and diffuse large B-cell lymphoma (DLBCL). The main toxicities of CAR-T include cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, cytopenia, and severe infection. It is still very difficult for CAR-T to kill tumor cells to the maximum extent and avoid damaging normal organs. Here, we report a case of DLBCL with persistent grade 4 thrombocytopenia and severe platelet transfusion dependence treated with CD19 CAR-T cells. We used sirolimus to inhibit the sustained activation of CAR-T cells and restore normal bone marrow hematopoiesis and peripheral blood cells. Moreover, sirolimus treatment did not affect the short-term efficacy of CAR-T cells, and DLBCL was in complete remission at the end of follow-up. In conclusion, sirolimus can represent a new strategy for the management of CAR-T cell therapy-related toxicity, including but not limited to hematotoxicity. However, further controlled clinical studies are required to confirm these findings.

The Role of mTOR Inhibitors in Hematologic Disease: From Bench to Bedside

The mTOR pathway plays a central role in many cellular processes, such as cellular growth, protein synthesis, glucose, and lipid metabolism. Aberrant regulation of mTOR is a hallmark of many cancers, including hematological malignancies. mTOR inhibitors, such as Rapamycin and Rapamycin analogs (Rapalogs), have become a promising class of agents to treat malignant blood diseases-either alone or in combination with other treatment regimens. This review highlights experimental evidence underlying the molecular mechanisms of mTOR inhibitors and summarizes their evolving role in the treatment of hematologic disease, including leukemia, lymphoma, myeloma, immune hemocytopenia, and graft-versus-host disease (GVHD). Based on data presented in this review, we believe that mTOR inhibitors are becoming a trusted therapeutic in the clinical hematologist's toolbelt and should be considered more routinely in combination therapy for the management of hematologic disease.

Successful sirolimus therapy of an aplastic anemia patient with chronic kidney disease: A case report

RATIONALE

It is very difficult to treat patients with aplastic anemia accompanied by chronic kidney disease. The nephrotoxicity of cyclosporine limits its use in these patients. Most of these patients also lack suitable sibling donors. Sirolimus, as a new type of immunosuppressive agent, has good therapeutic effect, lower toxicity, especially lower nephrotoxicity, thus attracting the attention of hematologists.

PATIENT CONCERNS

This 55-year-old Chinese male patient suffered from pancytopenia and renal insufficiency and has a poor quality of life.

DIAGNOSIS

The patient was diagnosed as severe aplastic anemia with chronic kidney disease-G3a.

INTERVENTIONS

We started the sirolimus therapy with the initial dose of 1 mg per day. Based on the good tolerability and clinical effect, we increased the dose of sirolimus to 2 mg per day after 2 weeks.

OUTCOMES

By taking sirolimus, the patient's peripheral blood cell count gradually increased, and he achieved blood transfusion independent, and eventually the blood cell count was completely normal.

LESSONS

We consider that sirolimus is a safe, effective, and well-tolerated oral drug that can be used as a treatment for aplastic anemia patients with chronic kidney disease.

Excellent response of severe aplastic anemia to treatment of gut inflammation: A case report and review of the literature

BACKGROUND

Cumulative evidence suggests that the aberrant immune responses in acquired aplastic anemia (AA) are sustained by active chronic infections in genetically susceptible individuals. Recently, the constant source to trigger and sustain the pathophysiology has been proposed to come from the altered gut microbiota and chronic intestinal inflammation. In this case, our serendipitous finding provides convincing evidence that the persistently dysregulated autoimmunity may be generated, at least in a significant proposition of AA patients, by the altered gut microbiota and compromised intestinal epithelium.

CASE SUMMARY

A 30-year-old Chinese male patient with refractory severe AA experienced a 3-month-long febrile episode, and his fever was refractory to many kinds of injected broad-spectrum antibiotics. When presenting with abdominal cramps, he was prescribed oral mannitol and gentamycin to get rid of the gut infection. This treatment resulted in a quick resolution of the fever. Unanticipatedly, it also produced an excellent hematological response. He had undergone three episodes of recurrence within the one-year treatment, with each recurrence occurring 7-8 wk from the gastrointestinal inflammation eliminating preparations. However, subsequent treatments were able to produce subsequent remissions and consecutive treatments were successful in achieving durative hematological improvements, strongly indicating an etiological association between chronic gut inflammation and the development of AA. Interestingly, comorbid diseases superimposed on this patient (namely, psychiatric disorders, hypertension, insulin resistance, and renal dysfunction) were ameliorated together with the hematological improvements.

CONCLUSION

Chronic gut inflammation may be responsible for AA pathogenesis. The comorbidities and AA may share a common etiological association.

Effects of the Total Saponins fromDioscorea nipponicaon Immunoregulation in Aplastic Anemia Mice

Dioscorea nipponica Makino, a popular folk medicine, exerts anti-inflammation properties. The present study investigated the therapeutic effect of the total saponins from Dioscorea nipponica Makino (TSDN) on aplastic anemia (AA) and possible immune regulation mechanisms. Using a mouse model of AA, three different doses of TSDN were orally administrated for 14 consecutive days. We first demonstrated that TSDN was found to be effective in alleviating pancytopenia with a hypocellular bone marrow as compared with AA model group. Moreover, gastrogavage administration of a medium dose of TSDN was found to dramatically increase the percentage of CD4+cells in bone marrow nucleated cells (BMNC) and restore the CD4+/CD8+ratio. The pro-inflammatory cytokine concentrations of IL-2 and IFN-γ were significantly decreased, and anti-inflammatory cytokine IL-4 was significantly increased in culture supernatant of BMNC. Further investigations showed that TSDN obviously inhibited Fas–FasL-induced BMNC apoptosis as well as effectively suppressed intracellular apoptosis protein of caspase-3 and -8 expressions. Taken together, these findings suggested that TSDN could alleviate AA by elevating the CD4+/CD8+T-cell ratio, inhibiting inflammatory Th1-cytokines, and exerting anti-apoptosis effects.