Mesenchymal stem cell infusion for enhancing hematopoietic recovery and addressing cytopenias in CAR-T cell therapy.

BACKGROUND: Chimeric antigen receptor (CAR)-T therapy has emerged as a promising treatment for hematologic malignancies. However, cytopenia remains one of the most frequent and challenging adverse effects of this therapy. METHODS: We conducted a retrospective analysis of 26 patients with relapsed/refractory aggressive B-cell lymphoma who received CAR-T therapy at our center. Subsequently, to investigate measures to address cytopenias following CAR-T therapy, we isolated and generated murine CAR-T cells and bone marrow-derived mesenchymal stem cells (MSCs), establishing a murine syngeneic CAR-T therapy model. We assessed the impact of MSC infusion on hematopoietic recovery post-CAR-T therapy by evaluating complete blood count, bone marrow hematopoietic stem cells and their subpopulations, bone marrow histomorphology, and hematopoiesis-related genes. RESULTS: All patients experienced cytopenias to varying degrees, with complete lineage involvement in half of the patients. Grade ≥ 3 cytopenias were observed in 88.46% of the patients. CAR-T therapy was associated with a higher incidence of biphasic, late-onset, or prolonged cytopenias. Survival analysis indicated that neutropenia and lymphopenia tended to be associated with better prognosis, whereas thrombocytopenia tended to be related to poorer outcomes. Through animal experiments, we discovered that MSCs infusion boosted HSCs and their long-term subpopulations, enhancing hematopoietic recovery, particularly in the megakaryocyte lineage, and mitigating bone marrow damage. Importantly, both in vitro and in vivo experiments demonstrated that MSCs did not compromise the activity or antitumor efficacy of CAR-T cells. CONCLUSIONS: Our findings propose MSCs infusion as a promising strategy to address cytopenias, particularly thrombocytopenia, after CAR-T therapy. This approach could help overcome certain limitations of cellular immunotherapy by enhancing hematopoietic recovery without compromising the efficacy of CAR-T cells. HIGHLIGHTS: 1 Cytopenia is a frequently observed adverse effect following CAR-T therapy, and it is often characterized by biphasic and prolonged patterns. 2 MSCs play a critical role in promoting hematopoietic recovery and mitigating bone marrow damage in a murine model of CAR-T therapy 3 The activity and antitumor efficacy of CAR-T cells were not impaired by MSCs.

Testosterone therapy as a novel approach to the management of cytopenias in myelodysplastic neoplasms: a review of literature and case report.

PURPOSE: To explore the potential of testosterone therapy in managing cytopenias in myelodysplastic neoplasm and investigate the link between hypogonadism and hematologic malignancies. METHODS: A case of a patient with intermediate-risk myelodysplastic neoplasm and hypogonadism treated with testosterone replacement therapy is presented. Testosterone, prostate specific antigen, and erythropoietin levels were checked prior to therapy initiation and 3 months after. Blood counts were monitored over time. This is followed by a literature review of testosterone use in myelodysplastic neoplasm and the prevalence of hypogonadism in hematologic malignancies. RESULTS: The patient showed sustained improvement in anemia with testosterone therapy and reported subjective improvement in his weakness and fatigue. This improvement occurred even in the setting of an undetectable follow up erythropoietin level. His repeat prostate specific antigen levels remained low, while testosterone levels showed marked improvement. The literature review demonstrated positive response rates for testosterone in treating myelodysplastic neoplasm-related cytopenias, and showed a higher incidence of hypogonadism in hematologic malignancies. CONCLUSION: Our review suggests that the use of testosterone in low and intermediate-risk myelodysplastic neoplasm is underexplored and poses to have significant potential as a future therapeutic agent, after careful consideration of risks and benefits. In addition, the incidence of hypogonadism in myelodysplastic neoplasm and its potential impact on exacerbating cytopenias in myelodysplastic neoplasm warrants further investigation.

Loss of Dnajc21 leads to cytopenia and altered nucleotide metabolism in zebrafish.

Mutations in the DNAJC21 gene were recently described in Shwachman-Diamond syndrome (SDS), a bone marrow failure syndrome with high predisposition for myeloid malignancies. To study the underlying biology in hematopoiesis regulation and disease, we generated the first in vivo model of Dnajc21 deficiency using the zebrafish. Zebrafish dnajc21 mutants phenocopy key SDS patient phenotypes such as cytopenia, reduced growth, and defective protein synthesis. We show that cytopenia results from impaired hematopoietic differentiation, accumulation of DNA damage, and reduced cell proliferation. The introduction of a biallelic tp53 mutation in the dnajc21 mutants leads to the development of myelodysplastic neoplasia-like features defined by abnormal erythroid morphology and expansion of hematopoietic progenitors. Using transcriptomic and metabolomic analyses, we uncover a novel role for Dnajc21 in nucleotide metabolism. Exogenous nucleoside supplementation restores neutrophil counts, revealing an association between nucleotide imbalance and neutrophil differentiation, suggesting a novel mechanism in dnajc21-mutant SDS biology.

Flow cytometry in the differential diagnosis of myelodysplastic neoplasm with low blasts and cytopenia of other causes.

Background: Myelodysplastic neoplasms (MDS) are characterized by cytopenia, morphologic dysplasia, and genetic abnormalities. Multiparameter flow cytometry (FCM) is recommended in the diagnostic work-up of suspected MDS, but alone is not sufficient to establish the diagnosis. Our aim was to investigate the diagnostic power of FCM in a heterogeneous population of patients with cytopenia, excluding cases with increased blast count. Methods: We analyzed bone marrow samples from 179 patients with cytopenia (58 MDS, 121 non-MDS) using a standardized 8-color FCM method. We evaluated the sensitivity, specificity, and accuracy of several simple diagnostic approaches, including Ogata score, extended Ogata score, the WHO and ELN iMDSFlow recommended "3 aberrations in two cell compartments method," and the combination of the Ogata score and "3 aberrations in two cell compartments method." The patients were followed until the diagnosis was confirmed, with a median follow-up of 2 months (range 0.2-27). Results: The combination of Ogata score and "3 aberrations in two cell compartments method" achieved the highest diagnostic accuracy (78%) with sensitivity and specificity 61% and 86%, respectively. When using only the "3 aberrations in two cell compartments method," the accuracy was 77% with a sensitivity of 72% and a specificity of 79%. The most frequently observed etiologies among the false positive cases were substrate deficiencies, inflammation/infection, or toxic effects. MDS can be excluded in all these cases after a thorough clinical evaluation and a relatively short follow-up. Conclusion: FCM remains an important but supplementary part in an integrated diagnostic process of MDS with low blasts. The combination of the Ogata score and the "3 aberrations in two cell compartments method" slightly improves accuracy compared to the detection of "3 aberrations in two cell compartments method" alone.

Unexpected diagnosis of WHIM syndrome in refractory autoimmune cytopenia.

ABSTRACT: WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome is a rare primary immunodeficiency predominantly caused by heterozygous gain-of-function mutations in the C-terminus of the gene CXCR4. These CXCR4 variants display impaired receptor trafficking with persistence of the CXCR4 receptor on the surface, resulting in hyperactive downstream signaling after CXCL12 stimulation. In turn, this results in defective lymphoid differentiation, and reduced blood neutrophil and lymphocyte numbers. Here, we report a CXCR4 mutation that in 2 members of a kindred, led to life-long autoimmunity and lymphoid hypertrophy as the primary clinical manifestations of WHIM syndrome. We examine the functional effects of this mutation, and how these have affected phosphorylation, activation, and receptor internalization.

Peripheral Blood and Bone Marrow Findings in Treatment-Naive Patients With Cytopenia(s)/Myeloid Neoplasms Harboring Both a Germline and a Somatic DDX41 Mutation.

DDX41 -associated cytopenia(s)/myeloid neoplasms ( DDX41 -C/MNs) are an emerging pathologic entity. We examined the hematopathologic findings in DDX41 -C/MNs with both a germline and somatic DDX41 mutation ( DDX41 -C/MNs-GS). We reviewed the peripheral blood and bone marrow (BM) findings from treatment-naive patients with DDX41 -C/MNs-GS. Thirty cases were identified: 10% (3/30) were classified as clonal cytopenia(s) of unknown significance (CCUS), 17% (5/30) as myelodysplastic neoplasm/syndrome (MDS) with <5% blasts, 20% (6/30) as MDS with 5% to 9% blasts, 20% (6/30) as MDS with 10% to 19% blasts, and 33% (10/30) as acute myeloid leukemia (AML). All patients were cytopenic; circulating blasts were rare (23%, 7/30). 63% (19/30) showed dysmegakaryopoiesis. Dyserythropoiesis and dysgranulopoiesis were uncommon; seen in 20% (6/30) and 7% (2/30), respectively. Sixty-six percent (19/29) of cases were normocellular; 43% (13/30) showed erythroid predominance. Flow cytometry revealed an unremarkable blast myeloid phenotype. Blasts were intermediate sized with round nuclei, distinct nucleoli, and light blue cytoplasm with azurophilic granules. The karyotype was predominantly normal (93%, 26/28). All germline mutations were deleterious: 53% (16/30) truncating and 47% (14/30) missense. The most common somatic variant was the R525H mutation in 70% (21/30). The BM diagnostic spectrum in DDX41- C/MNs that harbor both a germline and somatic DDX41 mutation is broad-ranging from CCUS to AML. We describe consistent hematopathologic findings that pathologists may expect in these cases.

Impact of post-transplant cyclophosphamide and splenomegaly on primary graft failure and multi-lineage cytopenia after allogeneic hematopoietic cell transplantation.

Primary graft failure (PGF) and multi-lineage cytopenia (MLC) increase the risk of nonrelapse mortality in allogeneic hematopoietic cell transplants (HCT). We evaluated the impact of post-transplant cyclophosphamide (PTCy) and splenomegaly on PGF and MLC for hematological malignancies. This study included patients with PTCy (N=84) and conventional graft-vs.-host disease prophylaxis (N=199). The occurrence of splenomegaly varied widely, ranging from 17.1 % (acute myeloid leukemia) to 66.7 % (myeloproliferative neoplasms). Ten patients (N=8 in the PTCy and N=2 in the non- PTCy) developed PGF, and 44 patients developed MLC (both N=22). PTCy and severe splenomegaly (≥20 cm) were risk factors for PGF (odds ratio (OR): 10.40, p<0.01 and 6.74, p=0.01 respectively). Moreover, severe splenomegaly was a risk factor for PGF in PTCy patients (OR: 10.20, p=0.01). PTCy (hazard ratio (HR) 2.09, p=0.02), moderate (≥15, <20 cm, HR 4.36, p<0.01), and severe splenomegaly (HR 3.04, p=0.01) were independent risk factors for MLC. However, in subgroup analysis in PTCy patients, only mild splenomegaly (≥12, <15 cm, HR 4.62, p=0.01) was a risk factor for MLC. We recommend all patients be screened for splenomegaly before HCT, and PTCy is cautioned in those with splenomegaly.

Infection risk in patients with autoimmune cytopenias and immune dysregulation treated with mycophenolate mofetil and sirolimus.

Introduction: Autoimmune cytopenias (AICs) are a group of disorders characterized by immune-mediated destruction of blood cells. In children, they are often secondary to immune dysregulation that may require long-lasting immunosuppression. Mycophenolate mofetil and sirolimus represent two well-tolerated options to treat these disorders, often as a steroid-sparing option. However, no data are available on the infection risk for patients undergoing long-lasting treatments. Patients and methods: The rate of severe infective events was calculated in episodes per 100 persons/months at risk (p/m/r) documented by the analysis of hospitalization charts between January 2015 and July 2023 of patients treated with mycophenolate mofetil or sirolimus given for isolated AIC or AICs associated with autoimmune lymphoproliferative syndrome (ALPS)/ALPS-like syndromes in two large Italian pediatric hematology units. Results: From January 2015 to July 2023, 13 out of 96 patients treated with mycophenolate mofetil or sirolimus developed 16 severe infectious events requiring hospitalization. No patients died. Overall infection rate was 0.24 person/*100 months/risk (95% CI 0.09-0.3). Serious infectious events incidence was higher in patients with ALPS-like compared to others (0.42 versus 0.09; p = 0.006) and lower in patients who underwent mycophenolate treatment alone compared to those who started sirolimus after mycophenolate failure (0.04 versus 0.29, p = 0.03). Considering only patients who started treatment at the beginning of study period, overall cumulative hazard was 18.6% at 60 months (95% CI 3.4-31.4) with higher risk of infectious events after 5 years in ALPS-like patients (26.1%; 95% CI 3.2-43.5) compared to other AICs (4%; 95% CI 0-11.4; p = 0.041). Discussion: To the best of our knowledge, this is the first study to describe the infectious risk related to mycophenolate and sirolimus chronic treatment in patients with AICs and immune dysregulation. Our data highlight that infection rate is very low and mainly related to the underlying hematological condition. Conclusions: Mycophenolate and sirolimus represent a safe immunosuppressive therapy in AICs and immune dysregulation syndromes.