Poor graft function after haploidentical stem cell transplantation with post-transplant cyclophosphamide.

This is a retrospective cohort study of consecutive adult patients who received a haploidentical-SCT (haplo-SCT) with post-transplant cyclophosphamide (PT-Cy) in a single centre. Poor graft function (PGF) was defined as the occurrence of either persistent neutropenia (ANC < 0.5 × 109/µL) with poor response to granulocyte colony-stimulating factors (G-CSF) and/or thrombocytopenia (platelets < 20 × 109/L) with transfusion dependence, with complete donor chimerism and without concurrent severe GVHD or underlying disease relapse, during the first 12 months after transplantation. Forty-four (27.5%) out of 161 patients were diagnosed with PGF. Previous CMV reactivation was significantly more frequent in patients with PGF (88.6% versus 73.5%, p = 0.04) and the number of reactivations was also higher in these patients. Besides, early CMV reactivations in the first 6 months post-SCT were also significantly more frequent among patients with PGF (88.6% versus 71.8% p = 0.025). Thirty-two percent of patients with PGF were treated with increasing doses of thrombopoietin-receptor agonists (TRA) and 7 patients were treated with a donor CD34 + selected boost. In total, 93.2% of patients reached adequate peripheral blood counts in a median time of 101 days (range 11-475) after diagnosis. PGF is a frequent complication after haplo-SCT with PT-Cy. CMV reactivation might be the most relevant factor associated to its development. Even when most patients recover peripheral counts with support therapy, there is a group of patients with persistent cytopenias who can effectively be treated with TRA and/or a boost of CD34 + selective cells.

Clinical grade production of IL-15 stimulated NK cells for early infusion in adult AML patients undergoing haploidentical stem cell transplantation with post-transplant cyclophosphamide.

BACKGROUND: Allogeneic stem cell transplantation is the treatment of choice for acute myeloid leukemia (AML) patients. Unmanipulated haploidentical transplantation (Haplo-HSCT) is commonly used for those AML patients who need a timely transplant and do not have a suitable matched donor, but relapse rates are still high, and improvements are needed. Adoptive immunotherapy using natural killer cells (NK cells) could be a promising tool to improved Haplo-HSCT but, to date, no optimal infusion and manufacturing protocols have been developed. STUDY DESIGN AND METHODS: In this study, we describe a quick and reproducible protocol for clinical-grade production of haploidentical donor NK cells using double immunomagnetic depletion and enrichment protocol and overnight IL-15 stimulation. RESULTS: Thus, we have obtained 8 viable and functional NK cell products that have been safely infused to five AML patients undergoing unmanipulated Haplo-HSCT. DISCUSSION: Our results demonstrate the safety and feasibility of manufactured NK IL15 cells obtained from an adult allogeneic donor in the setting of haploidentical transplantation for AML patients.

Allogeneic CD34-selected stem cell boost as salvage treatment of life-threatening infection and severe cytopenias after CAR-T cell therapy.

BACKGROUND: A variable incidence of profound cytopenia has been described in patients receiving chimeric antigen receptor T-cell (CAR-T) therapy for relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (ALL). This complication leads to severe infection in some cases, especially those who present additional risk factors including prior hematopoietic stem cell transplantation (HSCT). STUDY DESIGN AND METHODS: We report a case of breakthrough invasive fungal infection in a patient with prolonged neutropenia after CAR-T cell therapy administered for relapsed B-cell ALL after allogeneic haploidentical HSCT. RESULTS: After disease progression was discarded, therapy with antifungal agents, G-CSF and thrombopoietin analogue was started. However, no sign of haematological recovery or infection improvement was observed. A fresh mobilized selected CD34-stem cell boost from her haploidentical transplant donor was infused without further conditioning. Within 15 days of mobilized CD34-boost administration the patient showed complete resolution of both the aplasia and fungal infection. DISCUSSION: This case illustrates as proof-of-concept the efficacy and safety of selected CD34-stem cell boost from prior donor as salvage treatment of prolonged cytopenias after CAR-T cell therapy.

Post-transplant cyclophosphamide for GVHD prophylaxis compared to ATG-based prophylaxis in unrelated donor transplantation.

Post-transplant cyclophosphamide (PTCY) effectively prevents graft-versus-host disease after unmanipulated HLA-haploidentical HSCT. The use of PTCY in the unrelated donor HSCT setting is less explored. We conducted a retrospective study of 132 consecutive patients undergoing a matched or 9/10 mismatched unrelated donor HSCT in 4 centers in Spain, 60 with anti-thymocyte globulin (ATG)-based prophylaxis combined with MTX-CsA, and 72 using a PTCY-based regimen. Peripheral blood stem cells were used as graft in most patients (111 patients, 84%); mMUD donors were balanced between groups. Cumulative incidences of grades II-IV and III-IV acute GVHD at 100 days were lower in the PTCy group (46% vs. 67%, p = 0.008; 3% vs. 34%, p = 0.003), without statistically significant differences in the 2-year cumulative incidence of chronic moderate-severe GVHD. At 2 years, no significant differences were observed in overall survival, event-free survival, cumulative incidence of relapse, and non-relapse mortality. GVHD was the most frequent cause of NRM in the ATG group. No differences were observed between groups in the composite endpoint of GVHD-free and relapse-free survival. In this study, PTCy combined with additional immunosuppression after MUD/mMUD HSCT showed a reduction of aGVHD rate with safety results comparable to those obtained with the ATG-based prophylaxis.

Transjugular Intrahepatic Portosystemic Shunt for Very Severe Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome (VOD/SOS) after Unmanipulated Haploidentical Hematopoietic Stem Cell Transplantation with Post-transplantation Cyclophosphamide.

Hepatic veno-occlusive disease or sinusoidal obstruction syndrome (VOD/SOS) is a threatening complication after both autologous and allogeneic hematopoietic stem cell transplantation (HSCT), with high mortality rates despite early medical treatment, including the use of defibrotide (DF). We retrospectively analyzed 185 unmanipulated haploidentical (haplo-) HSCT with post-transplantation cyclophosphamide as graft-versus-host disease prophylaxis performed consecutively between 2011 and June 2019 in a single center. Seventeen patients (9.2%) were diagnosed with VOD/SOS. Based on revised European Society for Blood and Marrow Transplantation severity criteria, the VOD/SOS cases were classified as mild in 2 patients (11.7%), moderate in 2 (11.7%), severe in 2 (11.7%), and very severe in 11 (64.9%). Thirteen patients (76%) were treated with DF, including all patients with severe or very severe VOD/SOS, except 1 patient with CNS hemorrhage. Sixteen patients (94%) were alive at day +100 after HSCT. Seven patients (41%) with very severe VOD/SOS were treated with transjugular intrahepatic portosystemic shunt (TIPS) owing to rapid clinical or analytical deterioration or refractory hepatorenal syndrome despite medical treatment, including DF. TIPS insertion was performed at a median time since VOD/SOS diagnosis of 4 days (range, 1 to 28 days) without technical complications in any case. The median hepatic venous pressure gradient before and after TIPS treatment was 24 mmHg (range, 14 to 29 mmHg) and 7 mmHg (range, 2 to 11 mmHg), respectively, with a median drop of 16 mmHg (range, 9 to 19 mmHg). Following TIPS insertion, all patients showed clinical improvement with hepatomegaly, ascites, and renal failure resolution, and all showed analytical improvement with reduced alanine aminotransferase (ALT), creatinine, and international normalized ratio values, except for patient 2, whose indication for TIPS was refractory hepatorenal syndrome with a normal ALT level. The 6 patients who had initiated DF before TIPS insertion completed 21 days of treatment. All patients met the criteria for complete remission (CR) at a median of 8 days after TIPS insertion (range, 2 to 82 days). The 100-day overall survival was 100%. For patients with rapid progressive VOD/SOS, early TIPS insertion allowed completion of DF therapy. The use of TIPS together with DF resulted in CR and no associated complications with no VOD/SOS-associated mortality despite high severity. In our experience, timely and individualized use of TIPS significantly improves outcomes of very severe VOD/SOS after haplo-HSCT. Therefore, TIPS should be promptly considered in rapidly progressive cases.

Cytokine release syndrome after allogeneic stem cell transplantation with posttransplant cyclophosphamide.

Cytokine release syndrome (CRS) is a systemic inflammatory response with aberrant immune activation and immune hyperstimulation, that leads to increased cytokine levels and inflammation. CRS has been described after antibody and cellular-based therapies. The use of posttransplant cyclophosphamide (PTCy) as graft-vs-host disease (GVHD) prophylaxis in haploidentical hematopoietic stem cell transplantation (haplo-HSCT) has led to the extension of allogeneic HSCT to patients without HLA-identical donors. Furthermore, PTCy has also been introduced in matched and unrelated donor HSCT. However, description of incidence and clinical impact of CRS on outcomes in these patients is scarce. We retrospectively analyzed 107 consecutive haplo-HSCT and 39 HLA-identical HSCT with PTCy from 2010 to 2017 in our institution. We used published CRS criteria to identify 76% and 14% of patients who developed CRS after haplo-HSCT and HLA-identical HSCT, respectively. Most patients presented CRS grades 1 and 2. Only one patient from the whole series presented grade 3 CRS and required tocilizumab therapy. The use of peripheral blood stem cells (PBSC), as well as total nucleated cells infused were associated with an increased risk of CRS. Patients who presented CRS developed grade II-IV acute GVHD more frequently than those who did not (60% vs 28.6% respectively, P = .012). The development of CRS was not significantly associated with nonrelapse mortality or overall survival. CRS is a frequent complication after PBSC haploidentical T-repleted HSCT, but significantly less frequent after HLA-identical HSCT. Most cases are mild. Prompt identification allows adequate management of severe forms.

Successful Treatment of Severe Aspergillosis with Isavuconazole Therapy after Allogeneic Stem Cell Transplantation.

Invasive fungal infections are one of the main infectious complications in allogeneic stem cell transplantation (SCT). Triazoles (voriconazole, posaconazole) are the main prophylactic and therapeutic options for the treatment of invasive aspergillosis. However, pharmacological interactions and hepatotoxicity limit its use. Isavuconazole (ISV) is a recently approved azole with a promising interaction and safety profile. We present a case with invasive aspergillosis in the post-allogeneic SCT setting in a critically ill patient with severe multiorgan failure due to veno-occlusive disease. The patient was treated with ISV and B amphotericin during severe kidney and liver failure and multiple immunosuppressants, without significant drug-related toxicity and with favorable outcome. The interaction and safety profile of ISV is discussed along the reported experience. ISV can be an effective salvage therapy even in complex clinical situations with multiple potential interactions.

Factors predicting peripheral blood progenitor cell mobilization in healthy donors in the era of related alternative donors: Experience from a single center.

BACKGROUND: Poor mobilization results are unexpected after G-CSF-induced peripheral blood stem cell collection in healthy donors. However, 2%-5% of the donors are poor mobilizers. Factors predicting CD34+-cell yield after mobilization in related alternative donors are still poorly known. PATIENTS AND METHODS: Baseline characteristics and efficacy results of G-CSF induced mobilization of 159 adult healthy donors in our institution from 2008 to 2016 were retrospectively analyzed. All donors received 10 µg/kg of G-CSF once a day subcutaneously for 4 days. Leukapheresis started on the 5th day of G-CSF treatment. Donors were classified as poor mobilizers if they had less than 20 000 CD34 + cell/mL peripheral blood count in the 5th day of G-CSF treatment or if they needed three or more leukapheresis for graft collection. RESULTS: Age, weight, and platelet count before and after mobilization were significantly different between poor and good mobilizers. Poor mobilizers (n = 16) were older (50.6 vs 41.7 years, P = 0.002), weight lower (64 vs 75 kg, P = 0.00) and showed a lower platelet count before (199.5 vs 219.0 × 109 /L, P = 0.03) and after (192.5 vs 206 × 109 /L, P = 0.019) mobilization. In the multivariate analysis only the 30% of the variability of mobilization was explained by the model (sensitivity 80%, specificity 70%). CONCLUSION: In this cohort of healthy donors in a single institution, older age, less weight, and lower platelet count was associated with poorer mobilization. With clinical and analytic factors it is not possible to predict more than 30% of the variability. Further studies are needed to investigate new variables.

Mononuclear cell collection for extracorporeal photopheresis by using the "off-line" system: A comparative study between COBE Spectra and Spectra Optia devices.

BACKGROUND: Extracorporeal photopheresis (ECP) is an efficient and established therapy to treat acute and chronic graft vs host disease (GVHD). Using an "off-line" method, the first step (mononuclear cell [MNC] collection) is decisive, as long as a high MNC yield and purity in the collected product is desirable. Two "off-line" devices were compared: the COBE Spectra and the Spectra Optia (Terumo BCT), using both continuous and intermittent protocols. PATIENTS AND METHODS: Twelve patients with GvHD (7 acute/5 chronic) were enrolled between June 2014 and May 2015 and were alternatively assigned for each procedure to either the COBE Spectra or the Spectra Optia cell separator. Patients characteristics and procedure/product parameters were analyzed. RESULTS: Two hundred procedures (100 per device) were included. The Spectra Optia system showed higher total nucleated cells and MNC collection efficiencies (18.6(10.2-29.7) vs 7.9(4.1-14.8)% and 43.6(20.3-59.5) vs 23.3(11.4-37.1)%, P < .001) and monocyte and lymphocyte collection efficiencies (55.2(17.7-83.2) vs 22.8(9-38.9)% and 38.3(26.7-53.4) vs 22.2(9-38.9)%, respectively, P < .001). Absolute platelet loss (PL) and PL per liter of blood processed were significantly lower in the Spectra Optia group (22.9(18.3-28.1) vs 33.6(26.5-41.1)%, P < .001 and 3.7(3.1-4.5) vs 4.3(3.5-4.2)%, P = .01, respectively). However, granulocyte contamination was higher (4.5(1.3-36) vs 1.2(0.4-5.7)%, P < .001) and a higher product haematocrit was obtained with the Spectra Optia (1(0.5-1.6) vs 0.3(0.2-0.5)%, P < .001), without an impact on irradiation time. CONCLUSIONS: In our study, Spectra Optia proved to be safe and effective in collecting MNC with high yield and purity for ECP in GvHD.

Transient hemolysis due to anti-D and anti-A1 produced by engrafted donor's lymphocytes after allogeneic unmanipulated haploidentical hematopoietic stem cell transplantation.

BACKGROUND: Development of de novo alloantibodies against recipient's red blood cell (RBC) antigens by engrafted donor's lymphocytes is a known phenomenon in the setting of allogeneic hematopoietic stem cell transplantation (HSCT). This situation is usually clinically insignificant. We report a case of early clinically relevant hemolytic anemia in a blood group A1 D+ patient, due to a limited production of anti-D and anti-A1 produced by nonpreviously sensitized newly engrafted donor's immune system. CASE REPORT: A 31-year-old Caucasian woman, blood group A1 , D+, with Hodgkin's lymphoma, received an unmanipulated haploidentical allogeneic peripheral blood HSCT after a nonmyeloablative conditioning regimen. Donor blood group was A2 B, D-. The patient had an uneventful course until Day +34, when she developed clinically significant hemolytic anemia with a positive direct antiglobulin test. Anti-D and anti-A1 produced by the donor-engrafted lymphocytes were detected both in serum and in eluate. The hemolysis produced an accelerated group change, turning the patient's ABO group into A2 B 2 weeks after the detection of the alloantibodies. As the residual patient's RBCs progressively disappeared, anti-D and anti-A1 production decreased and were not detected in serum by Day +41. CONCLUSION: This case illustrates that de novo alloantibody production against ABO and D antigens by the newly engrafted donor's lymphocytes can occasionally cause clinically significant anemia. To our knowledge, this is the first case reported of clinically significant hemolytic anemia due to a transient anti-D anti-A1 alloimmunization after T-cell-repleted haploidentical HSCT.

Inhibitory killer cell immunoglobulin-like receptor (iKIR) mismatches improve survival after T-cell-repleted haploidentical transplantation.

Alloreactivity triggered by interaction between killer cell immunoglobulin-like receptors (KIRs) and natural killer (NK) cells plays a role in the graft-versus-tumor effect after hematopoietic stem cell transplantation (SCT). Our aim in this study was to evaluate this role in the setting of T-cell-repleted haploidentical SCT with postinfusion high-dose cyclophosphamide (PT-Cy). We included 33 patients. Among patient-donor pairs with at least 1 inhibitory KIR (iKIR) gene mismatch, event-free survival (EFS) and cumulative incidence of relapse 1 year after transplant were significantly better (85% vs. 37% [P = 0.008] and 18% vs. 46% [P = 0.041], respectively). A subanalysis in 12 patients with Hodgkin's lymphoma (HL) showed an improvement in EFS 1 year after transplant in those patients with KIR ligand mismatch (100% vs. 25%, P = 0.012), although overall survival (OS) was not affected (85% vs. 80%, P = 0.2). Eight of 12 patient-donors pairs presented iKIR mismatches. Of note, this outcome was better in the small subgroup, both for EFS (100% vs. 25%, P = 0.012) and for OS (100% vs. 37%, P = 0.004). Our data suggest that in the setting of T-cell-repleted haploidentical SCT with PT-Cy, iKIR mismatch is associated with improved survival, with particularly good results for both iKIR and KIR ligand mismatches in patients with HL.

Haplo-cord transplantation using CD34+ cells from a third-party donor to speed engraftment in high-risk patients with hematologic disorders.

Among the strategies to optimize engraftment of cord blood (CB) stem cell transplantation (SCT), single CB with the coinfusion of CD34(+) stem cells from an HLA-mismatched auxiliary donor (haplo-cord) provides a valid alternative for adult patients without a suitable donor. A total of 132 high-risk adult patients with hematological malignancies from 3 Spanish institutions underwent myeloablative haplo-cord SCT. The median age was 37 years and median weight was 70 kg; 37% had active disease. The median number of postprocessing CB total nucleated and CD34(+) cells was 2.4 × 10(7)/kg (interquartile range [IQR], 1.8 to 2.9) and 1.4 × 10(5)/kg (IQR, .9 to 2), respectively. Neutrophil engraftment occurred in a median of 11.5 days (IQR, 10.5 to 16.5) and platelet engraftment at 36 days (IQR, 25.5 to 77). Graft failure was 2% overall and only 9% for CB. Cumulative incidence of acute graft-versus-host disease (GHVD) grades II to IV was 21% and cumulative incidence of chronic GVHD was 21%. Median follow-up was 60 months (range, 3.5 to 163). Overall survival was 43.5%, event-free survival was 38.3%, nonrelapse mortality was 35%, and relapse was 20% at 5 years. Myeloablative haplo-cord SCT results in fast engraftment of neutrophils and platelets, low incidences of acute and chronic GVHD, and favorable long-term outcomes using single CB units with relatively low cell content. Moreover, CB cell dose had no impact on CB engraftment and survival in this study. Therefore, haplo-cord SCT expands donor availability while reducing CB cell dose requirements.

Prognostic impact of minimal residual disease analysis by flow cytometry in patients with acute myeloid leukemia before and after allogeneic hemopoietic stem cell transplantation.

Allogeneic stem cell transplantation (allo-SCT) has become the treatment of choice in patients with intermediate-risk and high-risk acute myeloid leukemia (AML). The quality of response to treatment, assessed in terms of detection of minimal residual disease (MRD), has been consistently associated with prognosis and clinical outcome in patients with AML. The aim of the present study was to evaluate the prognostic impact of analyzing MRD in bone marrow using 4-color multiparametric flow cytometry (MFC) in 29 patients with AML before and after allo-SCT. Eighteen patients who were shown to be MRD-negative [≤0.1% leukemia-associated immunophenotypes (LAIPs)] by MFC at transplantation and underwent allo-SCT had lower rates of relapse (15% vs. 66%, P = 0.045), better overall 1-yr survival (83% vs. 52%, P = 0.021) and a lower cumulative incidence of relapse (P = 0.032) than patients who were MRD-positive (>0.1%). All post-transplant MRD-positive patients underwent a therapeutic intervention after transplant (tapering of immunosuppression, donor lymphocyte infusion, or re-transplant) with the intention of preventing relapse. Disease was controlled and MRD disappeared in five of these patients. Disease recurred in the other seven patients. We can conclude that follow-up with MFC for the detection of MRD in AML before and after SCT is useful for predicting relapse. In the post-transplant setting, monitoring of MRD by MFC could be a key preemptive intervention.

Digital PCR Improves Sensitivity and Quantification in Monitoring CAR-T Cells in B Cell Lymphoma Patients.

Chimeric antigen receptor T cells (CAR-T) has emerged as a promising therapy, over 60% of patients fail to sustain a long-term response. The underlying factors that leads to the effectiveness of this therapy are not completely understood, CAR-T cell persistence and monitoring seems to be pivotal for ensuring a successful response. Various monitoring methods such as multiparametric flow cytometry (MFC) or quantitative PCR (qPCR) have been applied. Our objective is to develop digital PCR (dPCR) assays for detection and quantification of CAR-T cells, comparing them with MFC and qPCR. Samples taken at different follow-up times from 45 patients treated with CAR-T therapy were analyzed to assess the correlation between the different methodologies. dPCR presented a high correlation with MFC and qPCR (r = 0.97 and r = 0.87, respectively), while offering a higher sensitivity (0.01%) compared to MFC (0.1%) and qPCR (1%). dPCR emerged as an alternative and highly sensitivity method for monitoring CAR-T cell dynamics. This technique is well-suited for implementation in clinical practice as a complementary technique to MFC.

Single cord blood combined with HLA-mismatched third party donor cells: comparable results to matched unrelated donor transplantation in high-risk patients with hematologic disorders.

Matched unrelated donor (MUD) transplantation is the first alternative in the absence of a matched sibling donor. For patients without a suitable adult donor, we have adopted the dual stem cell transplantation protocol consisting of cord blood (CB) in combination with CD34(+) cells from a third party HLA-mismatched donor. We analyzed the outcomes of patients undergoing both procedures in a single center. Starting in 2004, a total of 20 patients with high-risk disease underwent 22 dual transplants and 25 patients underwent myeloablative MUD transplantation. The 30-day cumulative incidence of neutrophil engraftment was similar in both groups (91% and 95%), with a median time to engraftment of 14 and 16 days, respectively. Grade II-IV acute graft-versus-host disease was more frequent in the MUD group (40% versus 5%). Except for a tendency toward a higher incidence of viral hemorrhagic cystitis in the dual transplantation group, posttransplantation infectious events were comparable in the 2 groups. The 3-year cumulative incidence rates of relapse (41% versus 44%) and nonrelapse mortality (30% versus 25%) were similar in the MUD and dual transplantation cohorts. Estimated 3-year overall survival and disease-free survival were 47% and 41%, respectively, with no survival advantage for either group. In our experience, dual transplantation offers survival rates comparable to those from myeloablative MUD transplantation with similar nonrelapse mortality rates.

Advantages of high cell concentration prior to cryopreservation of initial leukapheresis in CAR-T cell therapy.

BACKGROUND: Chimeric antigen receptor (CAR) T-cell therapy is increasingly used in patients affected by B-cell lymphoma and acute lymphoblastic leukemia. For logistical reasons, initial apheresis products may be cryopreserved for shipment to manufacturing centers. Due to the characteristics of these patients, cells are often collected in large volumes, meaning more bags must be cryopreserved. This requires increased storage, time and monetary costs. In this context, we aimed to evaluate a high cell concentration cryopreservation protocol by centrifugation to standardize the initial CAR-T manufacturing procedure. MATERIALS AND METHODS: Sixty-eight processes of leukapheresis of 57 patients affected by refractory/relapsed B cell lymphoma and 9 patients affected by acute lymphoblastic leukemia who were eligible for anti-CD19 CAR-T cell treatment performed between June 2019 and October 2022 were analyzed. Whole blood count, percentage and number of T cells were assessed on the apheresis final product. The apheresis product, which was alternatively stored overnight at 4°C, was centrifuged, adjusting the volume to approximately 40 mL. The product was immediately cryopreserved to achieve a final cell concentration of 50-200×106 cells/ml for cryopreservation. RESULTS: Leukapheresis volume was reduced by almost fivefold (median: 185 to 40 mL), resulting in a higher product concentration in one bag. In addition, the number of non-target cells (monocytes, platelets and erythrocytes) was also reduced during the development of CAR T cell therapy, thereby maintaining T lymphocyte levels and providing a purer starting material. DISCUSSION: The advantages of the protocol include reducing economic costs, saving storage space, simplifying the manufacturing process, and facilitating shipping logistics. In conclusion, we present a validated, simple, and cost-effective cell enrichment processing protocol that provides high-quality cryopreserved products as starting material for the CAR-T cell manufacturing process.

Results of haploidentical transplant in patients with donor-specific antibodies: a survey on behalf of the Spanish Group of Hematopoietic Transplant and Cell Therapy.

Background: Donor-specific antibodies (DSAs) are IgG allo-antibodies against mismatched donor HLA molecules and can cause graft failure (GF) in the setting of haploidentical hematopoietic stem cell transplantation (haplo-HSCT). Our aim was to report the experience of the Spanish Group of Hematopoietic Transplant (GETH-TC) in DSA-positive patients who had undergone haplo-HSCT. Methods: We conducted a survey of patients who underwent haplo-HSCT in GETH-TC centers between 2012 and 2021. Data were collected on the DSA assay used, monitoring strategy, complement fixation, criteria for desensitization, desensitization strategies and transplant outcomes. Results: Fifteen centers from the GETH-TC responded to the survey. During the study period, 1,454 patients underwent haplo-HSCT. Seventy of the transplants were performed in 69 DSA-positive patients, all of whom lacked a suitable alternative donor; 61 (88%) patients were female (90% with prior pregnancies). All patients received post-transplant cyclophosphamide-based graft-versus-host disease prophylaxis. Regarding baseline DSA intensity, 46 (67%) patients presented mean fluorescence intensity (MFI) >5,000, including 21 (30%) with MFI >10,000 and three (4%) with MFI >20,000. Six patients did not receive desensitization treatment, four of them with MFI <5,000. Of 63 patients receiving desensitization treatment, 48 (76%) were tested after desensitization therapy, and a reduction in intensity was confirmed in 45 (71%). Three patients (5%) experienced an increase in MFI after desensitization, two of whom experienced primary GF. Cumulative incidence of neutrophil engraftment at day 28 was 74% in a median of 18 days (IQR, 15─20); six patients died before engraftment due to toxicity or infection and eight patients had primary GF despite desensitization in seven of them. After a median follow-up of 30 months, two-year overall and event-free survival were 46.5% and 39%, respectively. The two-year cumulative incidence of relapse was 16% and non-relapse mortality (NRM) was 43%. Infection was the most frequent cause of NRM, followed by endothelial toxicity. Multivariate analysis identified baseline MFI >20,000 as an independent risk factor for survival and an increase in titers after infusion as an independent risk factor for GF. Conclusions: Haplo-HSCT is feasible in DSA-positive patients, with high rates of engraftment after desensitization guided by DSA intensity. Baseline MFI >20,000 and increased intensity after infusion are risk factors for survival and GF.

False-positive Aspergillus antigenemia due to blood product conditioning fluids.

The presence of Aspergillus antigens in blood transfusion components from different manufacturers was analyzed. Galacomannans were found in transfused patients, pooled platelet concentrates, fresh frozen plasma, and packed red cells collected using Fresenius Kabi bags. Galacomannans were also found in blood collection anticoagulant and platelet additive solution from this manufacturer.

Evaluation of minimal residual disease by real-time quantitative PCR of Wilms' tumor 1 expression in patients with acute myelogenous leukemia after allogeneic stem cell transplantation: correlation with flow cytometry and chimerism.

Relapse remains the main cause of treatment failure in patients with acute myelogenous leukemia (AML) after allogeneic hemopoietic stem cell transplantation (SCT). The Wilms' tumor 1 gene (WT1) is reportedly overexpressed in >90% of patients with AML and thus can be useful for minimal residual disease (MRD) monitoring. The aim of this study was to evaluate the usefulness of WT1 expression as a relapse predictor marker in patients with AML after SCT and compare it with flow cytometry (FC) and chimerism studies. WT1 expression was assessed retrospectively using quantitative RT-PCR in bone marrow and peripheral blood from 21 patients. Patients were classified according to WT1 dynamics posttransplantation. Eleven of the 21 patients had low and stable WT1 levels. All of these 11 patients showed complete chimerism and negative MRD by FC and remained in complete remission with a median follow-up of 27 months (range, 18-98 months). In contrast, 10 of 21 patients showed WT1 overexpression after SCT, and 9 of these 10 patients relapsed. The incidence of relapse differed significantly between the 2 groups of patients according to WT1 expression post-SCT (P = .00003). Relapse in the 9 patients occurred at a median of 314 days (range, 50-560 days). Interestingly, in these patients, relapse was first predicted by WT1 (with negative FC and complete chimerism) in 7 patients. WT1 overexpression was correlated with disease burden in patients with AML before and after allogeneic SCT. In patients who relapsed, both medullary and extramedullary relapse were better anticipated by WT1 overexpression compared with FC and chimerism.

FLT3-ITD Expression as a Potential Biomarker for the Assessment of Treatment Response in Patients with Acute Myeloid Leukemia.

FLT3-internal tandem duplication (ITD) analysis is not typically performed in cDNA samples and is not considered an appropriate marker for monitoring measurable residual disease (MRD). The aims of this study were to compare FLT3-ITD mutation analysis in DNA and cDNA samples at diagnosis and to demonstrate the usefulness of its expression measurement as an MRD marker after allogeneic stem cell transplantation (allo-HSCT) or FLT3 inhibitor (FLT3i) administration. A total of 46 DNA and cDNA diagnosis samples, 102 DNA and cDNA post-allo-HSCT samples from 34 patients and 37 cDNA samples from 7 patients with refractory/relapse AML treated with FLT3i were assessed for the FLT3-ITD mutation through fragment analysis. In terms of sensitivity, the analysis of cDNA was superior to that of DNA, quantifying higher allelic ratio values in most cases at diagnosis, and thus optimizing the detection of minor clones and prognostic classification. Regarding the last sample before post-HSCT relapse, cDNA analysis anticipated relapse in most cases, unlike DNA analyses. With regard to the post-FLT3i follow-up, FLT3-ITD expression was reduced after the first FLT3i cycle when the treatment was effective, whereas it was not reduced in refractory patients. FLT3-ITD expression could be a useful additional biomarker at diagnosis and for the assessment of MRD after allo-HSCT and FLT3i in AML.