Mesenchymal Stem Cells in Aplastic Anemia and Myelodysplastic Syndromes: The "Seed and Soil" Crosstalk

There is growing interest in the contribution of the marrow niche to the pathogenesis of bone marrow failure syndromes, i.e., aplastic anemia (AA) and myelodysplastic syndromes (MDSs). In particular, mesenchymal stem cells (MSCs) are multipotent cells that contribute to the organization and function of the hematopoietic niche through their repopulating and supporting abilities, as well as immunomodulatory properties. The latter are of great interest in MDSs and, particularly, AA, where an immune attack against hematopoietic stem cells is the key pathogenic player. We, therefore, conducted Medline research, including all available evidence from the last 10 years concerning the role of MSCs in these two diseases. The data presented show that MSCs display morphologic, functional, and genetic alterations in AA and MDSs and contribute to immune imbalance, ineffective hematopoiesis, and leukemic evolution. Importantly, adoptive MSC infusion from healthy donors can be exploited to heal the "sick" niche, with even better outcomes if cotransplanted with allogeneic hematopoietic stem cells. Finally, future studies on MSCs and the whole microenvironment will further elucidate AA and MDS pathogenesis and possibly improve treatment

The Physiopathology of T- Cell Acute Lymphoblastic Leukemia: Focus on Molecular Aspects

T-cell acute lymphoblastic leukemia/lymphoma is an aggressive hematological neoplasm whose classification is still based on immunophenotypic findings. Frontline treatment encompass high intensity combination chemotherapy with good overall survival; however, relapsing/refractory patients have very limited options. In the last years, the understanding of molecular physiopathology of this disease, lead to the identification of a subset of patients with peculiar genetic profile, namely \u201cearly T-cell precursors\u201d lymphoblastic leukemia, characterized by dismal outcome and indication to frontline allogeneic bone marrow transplant. In general, the most common mutations occur in the NOTCH1/FBXW7 pathway (60% of adult patients), with a positive prognostic impact. Other pathogenic steps encompass transcriptional deregulation of oncogenes/oncosuppressors, cell cycle deregulation, kinase signaling (including IL7R-JAK-STAT pathway, PI3K/AKT/mTOR pathway, RAS/MAPK signaling pathway, ABL1 signaling pathway), epigenetic deregulation, ribosomal dysfunction, and altered expression of oncogenic miRNAs or long non-coding RNA. The insight in the genomic landscape of the disease paves the way to the use of novel targeted drugs that might improve the outcome, particularly in relapse/refractory patients. In this review, we analyse available literature on T-ALL pathogenesis, focusing on molecular aspects of clinical, prognostic, and therapeutic significance

Impact of intravascular hemolysis and multitreatment on thrombosis occurrence in autoimmune hemolytic anemia

Background Autoimmune hemolytic anemia (AIHA) is a clinically heterogeneous disease classified as warm (wAIHA) (direct antiglobulin test positive for IgG and IgG+C), cold (cAIHA, DAT+ for C), mixed (IgG+C with high titer cold agglutinins), and atypical (DAT-, IgA+, wIgM). An increased thrombotic risk has been described possibly due to the release of free Hb and nitric oxide depletion at endothelial surface, and to the proinflammatory autoimmune milieu. However, predictors of thrombosis in AIHA are still lacking and no guidelines for anticoagulant prophylaxis are available Aims to characterize the frequency and severity of thrombotic episodes and their relationships with AIHA features Methods we analyzed a large single-centre cohort of primary AIHA patients to evaluate the frequency, type, and severity of thrombotic episodes. We also evaluated the relationship with disease characteristics (AIHA type, blood counts, hemolytic markers) and therapies, with the Padua score for thrombotic risk (cancer/chemo-/radiotherapy in past 6 months, previous thrombosis, bedrest>3 days, known thrombophilia, surgery/trauma, age>70, cardiac/respiratory failure, myocardial infarction/stroke, obesity, ongoing hormonal treatment), and with the occurrence of AIHA-related complications and death Results Twenty-five out of 225 (11%) AIHA patients experienced a thrombosis during a median follow-up of 32 months (1-540), and 72% required hospitalization. Venous episodes were mainly pulmonary embolism (N=10), followed by deep venous thrombosis of lower limbs or splanchnic vessels (N=5 and N=2, respectively), thromboflebitis (N=3), and catheter-associated thrombosis (N=2); 2 myocardial infarction and 1 stroke were also registered. Of note, 5 patients had multiple thrombotic episodes (2 in 3, 3 in 1, and 5 in 1). Nine cases started low-molecular-weight heparin, 11 oral anticoagulants, 4 anti-platelets agents, and 1 died because of the event. Table 1 shows clinical data in patients with and without thrombosis: baseline LDH levels were significantly higher in patients experiencing thrombosis (p=0.02), whilst Hb, reticulocytes, and bilirubin levels were similarly distributed, indicating a prominent role for intravascular hemolysis in thrombosis. This is also strengthened by persistent LDH elevation at the time of thrombosis, whilst other AIHA parameters (Hb, reticulocytes, and bilirubin) were all significantly improved due to treatment. AIHA type, white blood cells and platelets were similar in the two groups. Regarding treatment, patients experiencing thrombosis had received more frequently 2, 3 or 4 lines. Considering specific treatments, the difference was particularly significant for rituximab and immunosuppressors. As expected, thrombotic episodes were more common among splenectomized patients. Among complications, infections were associated with thrombosis occurrence. The Padua score highlighted age and bedrest as the most frequently associated factors (40% and 28%, respectively) Conclusion thrombotic episodes occurred in 11% of AIHA patients, were mostly severe, and required hospitalization in the great majority of cases. Intravascular hemolysis, multitreatment, and infections were the major associated risk factors, while age and bedrest are important cofactors. The presence of underlying clinical and biological prothrombotic conditions, and the efficacy of different prophylactic/therapeutic anticoagulants need to be explored in larger prospective studie

Reduced 25-OH vitamin D in patients with autoimmune cytopenias, clinical correlations and literature review

Vitamin D deficiency is widespread in Western Countries and has been found related to autoimmune and hematologic disease incidence and clinical course. We evaluated vitamin D levels, vitamin D receptor (VDR) and T helper (Th)1, Th2 and Th17 immunomodulatory cytokines in patients with immune thrombocytopenic purpura (ITP, N = 44), primary autoimmune hemolytic anemia (AIHA, n = 35), Evans' syndrome (n = 5) and chronic idiopathic neutropenia (CIN, n = 19) and also tested vitamin D effect on the in vitro production of anti-erythrocyte autoantibodies. 25-OH-vitamin D levels were significantly lower and vitamin D receptor higher in patients than in controls. Among ITP cases, those with very low vitamin D levels displayed reduced platelet counts, irrespective of the bleeding history. In AIHA patients, LDH values negatively correlated with vitamin D levels in mixed forms, and reticulocyte counts were positively related with vitamin D. Considering treatment, AIHA patients who had been treated with 2 therapy lines or more showed lower mean 25-OH-vitamin D levels than those untreated or treated with one line of therapy only. IL-6, IL-10, IL-17 and IFN-\u3b3 levels were higher in patients versus controls, whereas TNF-\u3b1 was significantly reduced. Finally, vitamin D at concentrations of 10, 20, and 40 ng/mL reduced the in vitro production of anti-erythrocyte autoantibodies both in pokeweed-stimulated and unstimulated cultures. In conclusion, vitamin D is reduced in autoimmune cytopenias and correlate with disease severity, supporting its possible protective role against the development of autoimmunity. Literature review showed vitamin D deficiency reports both in onco- and in non onco-hematologic diseases with a relationship with disease severity/activity in myeloid and lymphoid neoplasms, as well as in sickle cell disease. Supplementation has produced weak results in autoimmune and hematologic diseases, and further studies are needed

Healthcare Resource Utilization in Autoimmune Hemolytic Anemia Patients: Analysis of 190 Cases from a Single Center

Autoimmune hemolytic anemia (AIHA) is a heterogeneous disease caused by autoantibody directed against erythrocyte antigens. It is usually considered a benign disease, easy to treat, and with low clinical impact. As a matter of fact, about 1/3 of cases present a severe onset and display a relapsing/refractory course that may lead to significant healthcare burden. However, data about healthcare direct and indirect costs and resource utilization are lacking, possibly due to the disease rarity and to the referral of difficult cases to 2ndary and 3rtiary centers. Here we retrospectively evaluated healthcare utilization in a single center cohort of primary AIHA patients, focusing on anemia severity, transfusion need, use of new highly expensive medications, splenectomy, and healthcare resource utilization (number of admissions and their length, outpatient visits). We studied 190 patients (72 M and 118 F, median age at diagnosis 57.7 yrs, range 2.2-94), followed-up for 4 yrs (0.1-45), classified in warm (W)AIHA (DAT positive for IgG and IgG+C), cold agglutinin disease, CAD (C), mixed (IgG+C with high titer cold agglutinins) and atypical (DAT-, IgA+, wIgM). In addition, hemoglobin levels at onset, hemolytic parameters (LDH, reticulocyte absolute counts, and bone marrow responsiveness index, BMRI), number of relapses, and of therapy lines were considered. Table 1 shows healthcare utilization indicators for AIHA patients divided according to AIHA type. On the whole, 121/190 (64%) required at least one hospital admission; the median number of hospital admissions was 1 (range 1-8), with 17/121 cases (9%) requiring 3 or more admissions. The higher frequency was observed in C+WAIHA, mixed and atypical cases (p=0.006). The median admission duration was 15 days, with 16 cases (13%) needing more than 30 days of admission. Concerning outpatients, median number of visits per year was 5, but 41/190 (22%) required more than a monthly visit. As regards therapeutic procedures, 103/190 (54%) required at least one transfusion; the median number of all transfusions received was 5, with 11/103 patients (11%) requiring more than 20 transfusions (the established threshold for chelation) and 6 more than 50. The distribution of transfusion need was significantly different among AIHA categories, with higher values observed in C+WAIHA, mixed and atypical cases (p=0.004). Considering transfusions as a function of follow-up length, the median was 2 per year, with 27 cases necessitating 4 or more (one subject about a weekly support). Highly expensive drugs were administered in 65/190 patients (34%), of whom 56 rituximab and 9 bortezomib, and splenectomy performed in 20/190 (11%) of patients. The administration of highly expensive drugs was significantly different among AIHA categories with higher rates observed in CAD and mixed cases (p=0.01). The analysis of hematologic parameters confirms the heterogeneity of the disease, with Hb values being particularly low in mixed and C+WAIHA (p=0.0001); the latter also showed lower absolute reticulocyte counts and BMRI (p=0.005 and p=0.008, respectively). As expected, admissions length and transfusions requirement were negatively correlated to Hb levels at onset (r=-0.26, p<0.001, and r=-0.18, p<0.01, respectively). Moreover transfusion requirement was positively correlated with a more severe hemolytic pattern (high LDH values r=0.21, p<0.01), and negatively with the bone marrow compensatory response (BMRI r=0.15, p<0.05). In conclusion, notwithstanding AIHA is usually considered a fairly benign disease, the clinical course of difficult cases (roughly 10-15%) require a reliable healthcare resource utilization representing a significant burden on the patient and the medical system

Clinical follow-up of 378 patients with autoimmune hemolytic anemia: prognostic impact of hemoglobin levels, autoantibody class, and reticulocytopenia at onset on the relapse risk and outcome

Autoimmune hemolytic anemia (AIHA) is greatly heterogeneous, from mild/compensated to life-threatening, due to autoantibody class/thermal amplitude and bone marrow compensatory response. Here we studied 378 patients (135 M and 243 F, median age 61 yrs, range 19-100), followed-up for 4.3 yrs (range 0.5-27), classified in warm (w)AIHA (DAT positive for IgG and IgG+C), cold agglutinin disease, CAD (C), mixed (IgG+C with high titer cold agglutinins) and atypical (DAT-, IgA+, wIgM). Anemia was categorized in Hb<6, 6-8, 8-10 and >10 g/dl, LDH expressed as fold upper the limit of normality (ULN) and reticulocytes as absolute count and index. The therapy lines were: steroids, rituximab, splenectomy, immunosuppressors, and transfusions/plasma exchange/erythropoietin. Hb was lower in IgG+C wAIHA and atypical cases (p<0.001), LDH higher in IgG+C wAIHA, mixed and atypical forms (p=0.01), and Hb and LDH values were negatively correlated (r=-0.25,p<0.001)[Table1]. Reticulocytes were lowerin CAD, mixed and IgG+C wAIHA (p<0.001) with inadequate reticulocytosis (p=0.01). Moreover, reticulocyte index was lower in cases with Hb<6 g/dL (p<0.001), with inadequate reticulocytosis (87 vs 70%,p=0.01).1st line therapy was administered in all cases but 25 CAD. 2nd line was mostly required in IgG+C wAIHA, mixed, and CAD (p=0.005). Ultra-refractory cases requiring 4 or> lines were mixed, atypical, and CAD. Patients with Hb<8 g/dL frequently required a 2nd line (51 vs 33%, p=0.004; p=0.03), or 3 or > lines (73% vs 26%, p<0.001). The following hazard ratios (HR) emerged from multivariate analysis: 3.2 (95% CI 1.4-7), 2.9 (1.4-6.2), 3.4 (1.6-7.5), for Hb<6, 6-8, and 8-10 g/dL compared to patients with Hb>10. Infections occurred in 14% of cases (mostly mixed AIHA, p=0.02), thrombosis in 10%, and acute renal failure (ARF) in 3% with no relationship with AIHA type/Hb. Evans\u2019 syndrome was frequent in mixed or atypical (p=0.04) and in severe forms (74% with Hb<8 g/dL vs 26%, p=0.005), and associated with higher relapse risk (HR 2.3, 95% CI 1.4-3.9). Seventy patients died, 12 because of AIHA complications. Mortality correlated with infections (HR 5.8),ARF (HR 7.6) and Evans\u2019 syndrome (HR 8.3). In conclusion, we found that anemia severity at onset was the major determinant of relapse risk. The lowest Hb levels were observed in patients with IgG+C WAIHA and atypical cases along with higher LDH levels and inadequate reticulocytosis, advising strict clinical observation in these patients