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.

A Case of Liver Failure Due to Dabigatran Treated with Venovenous Hemodiafiltration and Idarucizumab

Dabigatran etexilate, a direct thrombin inhibitor, was recently introduced in clinical use to prevent thromboembolic events in patients with risk factors (such as non-valvular atrial fibrillation or deep vein thrombosis). Dabigatran is not recommended in patients with creatinine clearance below 30 mL/min. More than 85% of the drug is eliminated by the renal route while the remaining part via the enteral route. Acute renal failure can result in an unexpected increase in serum levels of Dabigatran. In elderly, renal dysfunction, co-morbidity, and concomitant intake of different drugs could make the dosage of Dabigatran challenging. We present a case of an elderly man who suffered a severe accidental dabigatran intoxication with acute liver toxicity recovered after dialytic treatment and Idarucizumab.

The development of autoantibodies after allogeneic stem cell transplantation is related with chronic graft-vs-host disease and immune recovery

OBJECTIVE

Chronic graft-vs-host disease (GVHD) has certain similarities with autoimmune diseases and is associated with the development of various autoantibodies in some patients. In this study, we analyzed the occurrence of autoantibodies in 63 patients surviving longer than 3 months after an allogeneic haematopoietic stem cell transplantation (HSCT), with the aim of detecting a possible association between occurrence of autoantibodies and development of chronic GVHD and immune recovery after HSCT.

PATIENTS AND METHODS

The patients were screened every 3 months for the occurrence of the following autoantibodies: anti-nuclear (ANA), anti-mitochondrial (AMA), anti-smooth muscle (ASMA), anti-cardiolipin (ACLA), anti-liver-kidney microsomal (LKM), anti-DNA, anti-neutrophil cytoplasmatic (ANCA), and anti-thyroid antibodies. Peripheral blood immunophenotyping with anti-CD3, CD4, CD8, CD19, CD20, CD16, and CD56 antibodies was evaluated at the same intervals.

RESULTS

Autoantibodies were not found in 18 patients (29%), at least in one screening in 29 patients (46%), and in all screenings in 16 patients (25%). ANA were found in 41 patients (65%), AMA in 4 (6%), ASMA in 4 (6%), ANCA in 7 (11%), ACLA in 1 (2%), anti-thyroid antibodies in 3 (5%), and anti-DNA in 2 (3%). More than one antibody occurred in 16/63 (25%) positive patients. ANA was significantly more frequent in patients with chronic GVHD and, among these, in those with the extensive form. The nucleolar pattern of immunofluorescence of ANA but not its titer was correlated with the extension of chronic GVHD. Patients who developed autoantibodies had higher CD20(+) cell blood counts than negative patients in the third month (p=0.006), ninth month (p=0.061), and twelfth month (p=0.043).

CONCLUSION

We conclude that patients with chronic GVHD, particularly those with an extensive involvement, were likely to develop autoantibodies and have a faster B-cell recovery, suggesting a role of B cells in the pathogenesis of chronic GVHD.

Caspofungin as first line therapy of pulmonary invasive fungal infections in 32 immunocompromised patients with hematologic malignancies

Invasive Fungal Infections (IFI) remain a severe and major complication among patients with hematologic diseases, but the recent availability of new antifungal agents (echinocandins and new azoles) have improved the chance of cure. Caspofungin (Cancidas-Merck) is a large lipopeptide molecule able to inhibit the enzyme complex 1,3-d-glucan synthetase; this action specifically damages the fungal cell wall. Caspofungin (CAS) is active, in vitro and in vivo, against most Candida species and Aspergillus species. We report on our experience with this drug as first-line therapy for proven or probable pulmonary IFI in immunocompromised patients with hematologic malignancies. Thirty-two consecutive patients (20 males and 12 females, with a median age of 52 yr) have been treated with CAS (27 acute leukemias, 1 chronic leukemia, 3 lymphomas and 1 multiple myeloma). Sixteen patients (50%) had a relapsed or resistant hematologic disease, while 12 patients were in complete remission and 4 were at onset of disease; 8/32 (25%) developed IFI after a hematopoietic stem cell transplant (HSCT) procedure. Seven out of 32 patients (22%) had a proven pulmonary IFI (7/7 Aspergillosis) and 25 (78%) had a probable IFI with pulmonary localization as defined according to international consensus. Thirty-one patients (97%) had less than 1000 granulocytes/mL at onset of infection and at the start of CAS therapy. The CAS was given at the dose of 70 mg on day 1, followed by 50 mg/day. Median duration of CAS therapy was 20 d (range 8-64); all the 31 neutropenic patients received concomitant granulocyte colony-stimulating factor (G-CSF). The overall response rate was 56% (18/32) with 12/18 complete responses and 6/18 partial responses; two patients (6%) had a stable disease. Twelve out of 32 (38%) did not respond and seven died of mycotic infection. Univariate analysis showed that granulocytes recovery (>500/mL vs. <500/mL) and status of hematologic disease (remission/onset vs. refractory/relapsed) were significantly associated to favourable outcome. No clinical adverse events (AE) were reported and only a grades I and II transient increase of serum alkaline phosphatase and/or transaminases occurred in 4/32 (12%) patients. After CAS therapy six non-responders and six cases with a partial or stable response were rescued with voriconazole. Two out of six patients (33%) in the former group and 6/6 (100%) in the latter obtained a complete resolution of IFI. Our experience suggests an efficacy of CAS, in combination with G-CSF, as first-line treatment of proven or probable IFI with pulmonary localization. The drug was well tolerated and there were no significant hepatic AE even in patients receiving CAS with cyclosporine after a HSCT. A significant proportion of non-responders or partial responders to CAS can be rescued with a subsequent voriconazole-based therapy.