Stem Cells mobilization and collection in allogeneic related and unrelated donors: a single center experience with focus on plerixafor.

INTRODUCTION: Poor CD34 + cells mobilization in allogeneic donors could affect transplant outcome. In a subgroup of patient mobilization with granulocyte colony-stimulating factor (G-CSF) alone is unsatisfactory, and Plerixafor could be used to enhance CD34 + cells release from bone marrow niche. MATERIALS AND METHODS: We conducted a retrospective single-center, cohort study on healthy allogeneic donors both related and unrelated, treated by Udine Transfusion Center over the last 10 years (2012-2022). In the 195 allogeneic donors treated we analyzed age, sex, body weight, BMI, comorbidities, G-CSF dosage and even baseline white blood cell count as possible predictor of insufficient CD34 + cells mobilization on day 5. In the subgroup of related donors we evaluated even baseline CD34 + cells (measured before mobilization start). Processed donor blood volume, collection efficiency and apheresis product were examined. Additionally a comparative analysis was conducted between G-CSF alone treated donors and poor mobilizing ones, in which Plerixafor was administered at a dose of 0.24 mg/kg as a pre-emptive or rescue agent. RESULTS: In 9 donors, due to poor mobilization (defined as CD34 + < 20/µL or estimated yield < 1 ×106 kg/recipient body weight), the use of plerixafor was necessary. PLX at a dose of 0.24 mg/kg was administered 5 h before collection, inducing an average increase of 5.1 (1.7-12.6) in CD34 + circulating cells. In this subgroup of patients, BMI and weight were significantly lower (p = 0.03). Interestingly, baseline CD34 + cells (measured before the onset of mobilization) also seems to predict poor mobilization (p = 0.003). In donors additionally treated with Plerixafor compared to those who received G-CSF alone, collection efficiency was higher (p = 0.02) and CD34 + cells collected were comparable (p = 0.2). Side effects related to the administration of plerixafor, if they occurred, were well tolerated. CONCLUSIONS: Plerixafor is a safe and effective drug in the rescue and prevention of poor mobilization. New prospective studies on allogeneic donors should be performed to increase the treatable population to avoid inadequate collection and mobilization. New laboratory predictors such as baseline CD34 + cells should be investigated in larger cohorts and then used as early screening.

Impact of Cryopreservation of Peripheral Blood Stem Cells (PBSC) in Transplantation from Matched Unrelated Donor (MUD).

Background: Cryopreservation of PBSC for allogenic hematopoietic stem cell transplantation (allo-HSCT) was implemented due to the current Coronavirus 2019 pandemic. The impact of match unrelated donor (MUD) graft freezing on the outcome of allo-HSCT in terms of hematological recovery, graft versus host disease (GVHD), and survival are still controversial. Methods: In this study, we compared graft composition, clinical characteristics, and outcome of 31 allo-HSCT from MUD cryopreserved PBSC (Cryo Group) with 23 matched-pair allo-HSCT from fresh MUD PBSC (Fresh Group) performed in our center between January 2020 and July 2021. Results: No significant differences were recognized in clinical characteristics of patients, donors, and transplants between the Cryo and Fresh groups except for a better prognostic comorbidity index (HCT-CI) of the Cryo group. In the Cryo Group, the median time from apheresis to cryopreservation was 46.0 h (range 23.8−53.5), while the median time from cells collection and reinfusion was 13.9 days (range 5.8−28.1). In the Fresh Group, median time from apheresis to reinfusion was 35.6 h (range 21.4−51.2). The number of viable (7-AAD negative) CD34+ cells per kg patient infused was significantly lower in the Cryo Group (5.2 ± 1.9 × 106/kg vs. 7.0 ± 1.3 × 106/kg; p < 0.001). Indeed, there was a 36% (11−70) median loss of viable CD34+/kg cells after freezing. All patients engrafted: median time to neutrophil engraftment (>0.5 × 109/L) was 13.5 days (range 12−15) for Cryo Group and 14 days (range 13−16) days for Fresh Group (p = 0.522), while the median time to platelet engraftment (>20 × 109/L) was, respectively, 14 (range 12−18) and 15 (range 12−17) days (p = 0.904). The incidence of grade ≥ 2 acute GVHD was similar in the two groups (56.5% Cryo Group vs. 60.0% Fresh Group; p = 0.832) and no differences in terms of OS (p = 0.090), PFS (p = 0.200) and TRM (p = 0.970) were observed between the Cryo and Fresh groups. Conclusions: In our series, no differences between the Cryo and Fresh groups were found in engraftment, grade ≥ 2 acute GVHD incidence, OS, PFS, and TRM despite a lower CD34+ infused dose in the Cryo Group. Frozen PBSCs could be considered a safe option also for allo-HSCT from MUD but a higher amount of PBSC should be collected to warrant an adequate viable CD34+ post-thawing.

Low levels of ADAMTS-13 with high anti-ADAMTS-13 antibodies during remission of immune-mediated thrombotic thrombocytopenic purpura highly predict for disease relapse: A multi-institutional study.

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a life-threatening immune-mediated thrombotic microangiopathy. Daily therapeutic plasma exchange (TPE) and the optimized use of rituximab have strikingly improved the outcome of this disease, however the rate of disease recurrence remains high. Specific predictors of relapse in patients in remission can be relevant for an optimal patient management. In this study, we aimed to identify predictive variables of disease relapse in a multicenter cohort of 74 out of 153 iTTP patients. They were tested at different time points during remission for the levels of ADAMTS-13 activity and autoantibody, and did not receive pre-emptive treatment for ADAMTS-13 activity deficiency during remission. The results showed that the association of ADAMTS13 activity ≤20% with a high anti-ADAMTS-13 titer at remission, and the time to response to first line treatment ≥13 days, were independent predictive factors of disease relapse. In addition, the use of rituximab in patients with exacerbation or refractoriness to TPE was significantly associated with reduced relapse rate. By Cox regression analysis, patients with ADAMTS-13 activity ≤20% plus anti-ADAMTS13 antibody titer ≥15 U/mL at remission had an increased risk of relapse (HR 1.98, CI 95% 1.087-3.614; P < .02). These findings may help to outline more personalized therapeutic strategies in order to provide faster and sustained responses to first-line iTTP treatment and prevent relapses in these patients.

Extracorporeal photochemotherapy in heart transplant rejection: A single-center experience.

BACKGROUND: The addition of extracorporeal photochemotherapy (ECP) to standard immunosuppressive therapy has been suggested to be beneficial in the treatment of recurrent/persistent heart rejection. METHODS: We reviewed medical data of heart transplant recipients who received ECP between 2010 and 2016 at our institution. RESULTS: During the study period, eight patients underwent nine ECP courses. The median time from transplant to ECP was 18 months (range 9-54). Indications for ECP were recurrent rejection in 6 patients, persistent rejection in 1 patient and mixed rejection with hemodynamic compromise in 1 patient. Additional criteria for patients' selection were represented by relevant comorbidities limiting the increase of immunosuppressive therapies. ECP was performed on an outpatient basis in 6 out of 8 patients. The median ECP duration was 12 months (range 1-18). Three out of 8 patients responded to ECP showing negative endomyocardial biopsies at the end of treatment. No additional rejection episodes were observed at their follow up (at 44, 72 and 31 months). Four of 8 patients failed to respond to ECP treatment, one patient has been judged not evaluable. Reduction of immunosuppressive therapies was obtained in all 3 responsive patients but also in 3 patients with a stable grade of rejection. The median duration of the follow up was 26 months (range 6-80). Two patients died at 6 and 21 months after beginning ECP. Survival after ECP was 78.2% at 26 months. No adverse effect or infectious complications associated with ECP were reported. CONCLUSIONS: The low response rate (37.5%) in our case series could be partially explained by patient selection, the treated patients representing a high-risk sub-set group. Further studies to provide evidence of a role for ECP in heart rejection treatment or prophylaxis are needed.

Extracorporeal Photopheresis for Treatment of Acute and Chronic Graft Versus Host Disease: An Italian Multicentric Retrospective Analysis on 94 Patients on Behalf of the Gruppo Italiano Trapianto di Midollo Osseo.

BACKGROUND: Extracorporeal photopheresis (ECP) is considered a valid second-line treatment for acute and chronic graft versus host disease (GVHD). METHODS: Ninety-four patients with acute GVHD (aGVHD) (n = 45) and chronic GVHD (cGVHD) (n = 49), retrospectively recruited in 6 Italian centers, were submitted to ECP for second-line treatment. At the time of ECP, 22 (49%) and 23 (51%) of 45 patients with aGHVD were nonresponsive and in partial remission (PR) after steroids, respectively, and all the 49 patients with cGVHD were steroid refractory. RESULTS: Forty-one (91%) of 45 patients with aGVHD achieved complete remission (CR) after ECP. Fifteen (33%) of 45 patients developed cGVHD. The CR rate in patients who started ECP being nonresponsive and in PR after steroid was 86% and 96%, respectively. After a median follow-up of 20 months (range, 2-72), 15 (33%) of 45 patients developed cGHVD and 16 (35%) of 45 patients died, in 3 cases for aGVHD. A trend for a better survival was seen among patients who started ECP in PR after steroid (80% vs 50% at 2 years; P = 0.07). Overall, 22 (45%) of 49 patients and 17 (35%) of 49 patients with steroid refractory cGHVD achieved CR and PR after ECP, respectively. After a median follow-up of 27 months, 44 (90%) of 49 patients are alive, 21 of whom (48%) are on steroid. CONCLUSIONS: Extracorporeal photopheresis is confirmed as an effective second-line treatment in both aGVHD and cGVHD, because it can induce a response in more than 80% of the patients and a long-term survival in at least 50% of the cases.

Pregnancy associated thrombotic thrombocytopenic purpura: Practical issues for patient management.

Thrombotic thrombocytopenic purpura (TTP) is a severe, life-threatening disease that needs urgent diagnosis and prompt therapeutic intervention. In pregnant women TTP may complicate the course of gestation putting mother and child at vital risk. Differential diagnosis with other obstetric and medical disorders may be difficult due to the overlap of several clinical and laboratory findings. Our understanding of the pathophysiology of TTP has allowed ADAMTS13 testing to have a central role in confirming the clinical diagnosis but the main limitation is that an ADAMTS13 assay is not available in "real time". Here we report the clinical course and treatment outcome of two young women with clinical manifestations of pregnancy associated TTP and briefly discuss the main topics of disease diagnosis and management.

Efficacy and safety of peripheral blood stem cell mobilization and collection: a single-center experience in 190 allogeneic donors.

BACKGROUND: In the past two decades peripheral blood stem cells (PBSCs) have increasingly replaced marrow as stem cells source for allogeneic transplantation. The PBSC donation initially applied only to related donors; later, due to the safety of the procedure, it was extended to unrelated donors. STUDY DESIGN AND METHODS: We have retrospectively collected data regarding mobilization, collection, and short- and long-term follow-up of 190 consecutive donors, 174 related and 16 unrelated. All donors followed a standard protocol for mobilization and underwent at least one PBSC collection. Follow-up in related donors was performed every 4 months in the first year and then annually, with no time limits, while unrelated donors were monitored for 10 years. RESULTS: All 190 donors completed the established mobilization protocol. The mobilizing capacity was significantly greater in males and in donors less than 60 years old. No case of major toxicity by granulocyte-colony-stimulating factor was found, nor thromboembolic events. The total dose of CD34+/recipient (median 5.8×10(6)/kg recipient/body weight) was statistically correlated with age, CD34+ before and after mobilization, and collection efficiency. Compliance to follow-up was 66%, with a significant difference between related and unrelated (63% vs. 100%, p=0.03). During follow-up no significant abnormalities in hematologic variables or hematologic malignancies were reported. CONCLUSION: Our study allowed us to define the PBSC donation as "a safe procedure for the donors," with short- and long-term effects limited to a small percentage of donors and "effective for the recipient," due to the dose of collected CD34+, adequate for transplantation in almost all recipients.

[Use of virus-inactivated plasma in apheresis treatment of thrombotic thrombocytopenic purpura: preliminary data]. / Plasma virus-inattivato nella terapia aferetica della porpora trombotica trombocitopenica: studio e dati preliminari.

Plasma exchange (TPEx) with fresh frozen plasma (FFP) or cryosupernatant plasma infusion is the treatment of choice for thrombotic thrombocytopenic purpura (TTP). The authors evaluate the preliminary data of the multicenter SIdEM study that compares virus-inactivated plasma with fresh frozen plasma (FFP) or cryosupernatant plasma in the apheretic treatment of TTP.