Antibody, cell-mediated response and infection susceptibility in allogeneic hematopoietic stem cell recipients after COVID-19 mRNA vaccination.

BACKGROUND: Patients undergoing allogeneic stem-cell transplantation (allo-SCT) have reduced responses to vaccines due to immunosuppressive status linked to GvHD prophylaxis and treatment. In our study, we compared humoral responses to anti-SARS-CoV-2 mRNA vaccine, and infection onset, according to patients and transplant features; we also evaluated cellular response in patients without seroconversion. METHODS: We tested antibodies titer after second and third vaccine doses. Antibodies were detected through an immune-enzymatic assay. In a patients' subgroup without seroconversion, we tested cell-mediated responses evaluating interferon-gamma release by T-lymphocytes exposed to virus spike protein. RESULTS: Seroconversion rate increased from 66% at 30 days to 81% at 90 days after the second dose; it was 97% at 150 days after the third dose. We found a significant association between seroconversion after the second dose and two variables: shorter interval between allo-SCT and vaccination; ongoing immunosuppression. Twelve of 19 patients (63%) without antibodies after the second dose did not show cellular responses. Nineteen percent of patients developed SARS-CoV-2 infection after the third dose, with favorable outcome in all cases. Patients within 12 months after allo-SCT showed a significantly higher infection risk. CONCLUSIONS: Our study suggests that an interval shorter than 12 months between allo-SCT and first vaccine dose and/or ongoing immunosuppression were associated with humoral and cellular response deficiency after two doses. Third dose induced an increased and sustained humoral response in the majority of patients. However, patients within 1 year after allo-SCT remained at higher infection risk and may be candidate for prophylaxis with anti-SARS-CoV-2 monoclonal antibodies.

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.

A multicentre, multinational, prospective, observational registry study of defibrotide in patients diagnosed with veno-occlusive disease/sinusoidal obstruction syndrome after haematopoietic cell transplantation: an EBMT study.

Severe hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a potentially life-threatening complication of haematopoietic cell transplantation (HCT). This multinational, prospective, observational study (NCT03032016), performed by the EBMT, enrolled patients treated with defibrotide from April 2015 to July 2018. This analysis focused on defibrotide-treated patients with VOD/SOS post-HCT. The primary endpoint was incidence of serious adverse events (SAEs) of interest up to 12 months post-HCT in patients with severe VOD/SOS. Overall, 104 defibrotide-treated patients with VOD/SOS post-HCT were enrolled: 62 had severe VOD/SOS and comprised the primary study population, including 36 with multi-organ dysfunction/failure (MOD/MOF). SAEs of interest occurred in 20 of 62 (32%) severe VOD/SOS patients; the most common by category were infection (24%) and bleeding (13%). In patients with severe VOD/SOS, the Kaplan-Meier-estimated Day 100 survival rate was 73% (95% CI: 60%, 82%) with VOD/SOS resolution by Day 100 in 45 of 62 (73%) patients. MOD/MOF resolved in 19 of 36 (53%) patients with MOD/MOF at VOD/SOS diagnosis. Results from this multicentre registry study build on prior defibrotide studies supporting the utility of defibrotide for the treatment of VOD/SOS post-HCT. These results provide additional real-world evidence of the effectiveness and safety of defibrotide in patients with VOD/SOS post-HCT.

Risk Factors and Outcomes of Infections by Multidrug-Resistant Gram-Negative Bacteria in Patients Undergoing Hematopoietic Stem Cell Transplantation.

The objective of this study was to determine risk factors and outcomes of infections by multidrug-resistant gram-negative (MDR GN) bacteria in 241 recipients of hematopoietic stem cell transplantation (HSCT). The cumulative incidence of infections was 10.5% (95% CI, 12.0% to 25.8%), with 57% of infections occurring during the period of severe neutropenia (neutrophil count < .1 × 106/L). In multivariate analysis, allogeneic transplant and colonization with MDR GN bacteria at admission to the transplant unit were significantly associated with an increased risk of infection. Although we observed neither transplant-related mortality (TRM) nor deaths due to infections by MDR GN bacteria after autologous transplant, in the allogeneic setting a significant difference was reported in terms of overall survival (OS) and TRM between patients who developed infections and those who did not (1-year OS, 39% versus 68%; 1-year TRM, 42% versus 19%). In multivariate analysis, refractory disease and development of grades III to IV graft-versus-host disease (GVHD) were factors that affected both TRM and OS, whereas occurrence of infections by MDR GN pathogens significantly reduced OS. We conclude that eligibility to allogeneic HSCT in MDR GN bacteria carriers should be carefully evaluated together with all other factors that independently influence outcome (disease status, donor, and GVHD risk).

Low-dose rituximab in adult patients with idiopathic autoimmune hemolytic anemia: clinical efficacy and biologic studies.

This prospective study investigated the efficacy, safety, and response duration of low-dose rituximab (100 mg fixed dose for 4 weekly infusions) together with a short course of steroids as first- or second-line therapy in 23 patients with primary autoimmune hemolytic anemia (AIHA). The overall response was 82.6% at month +2, and subsequently stabilized to ∼ 90% at months +6 and +12; the response was better in warm autoimmune hemolytic anemia (WAIHA; overall response, 100% at all time points) than in cold hemagglutinin disease (CHD; average, 60%); the relapse-free survival was 100% for WAIHA at +6 and +12 months versus 89% and 59% in CHD, respectively, and the estimated relapse-free survival at 2 years was 81% and 40% for the warm and cold forms, respectively. The risk of relapse was higher in CHD and in patients with a longer interval between diagnosis and enrollment. Steroid administration was reduced both as cumulative dose (∼ 50%) and duration compared with the patient's past history. Treatment was well tolerated and no adverse events or infections were recorded; retreatment was also effective. The clinical response was correlated with amelioration biologic markers such as cytokine production (IFN-γ, IL-12, TNF-α, and IL-17), suggesting that low-dose rituximab exerts an immunomodulating activity. This study is registered at www.clinicaltrials.gov as NCT01345708.

Low-dose rituximab in adult patients with primary immune thrombocytopenia.

BACKGROUNDS: Rituximab 375 mg/m(2) weekly for 4 wks has significant activity in adults with primary immune thrombocytopenia (ITP). In this setting, several evidences support the possible use of lower doses of rituximab. OBJECTIVES: To investigate the activity of low-dose rituximab as salvage therapy in previously treated symptomatic ITP. METHODS: Forty-eight adult patients were treated prospectively with rituximab 100 mg weekly for 4 wks. RESULTS: Overall and complete responses (CR) (platelet level ≥ 50 and 100 × 10(9) /L) were 60.5% and 39.5%, respectively. In responders, the median time to response was 35 d (range: 7-112 d). The median time of observation was 18 months (range 3-49 months). Sixteen of 29 responding patients (55%) relapsed and 14 needed further treatments. The 12- and 24-month cumulative relapse-free survival was 61% and 45%, respectively. In univariate analysis, CR rate was in inverse relation with weight OR=0.95, CI(95%) [0.91; 0.99] (P=0.019) and age OR=0.96, CI(95%) [0.93; 0.99] (P=0.047). Cox regression model showed that relapse probability increases as weight (HR=1.06, CI(95%) [1.0031; 1.111]) and period between diagnosis and rituximab therapy (HR=1.01, CI(95%) [1.002; 1.017]) increase. One patient developed an interstitial pneumonia 1 month after the end of rituximab treatment. No other infectious, hematologic or extra-hematologic complications were documented during follow-up. CONCLUSIONS: Low-dose rituximab is active in ITP but has moderate long-term effect. A comparative study with standard dose is warranted.

Dexamethasone plus rituximab yields higher sustained response rates than dexamethasone monotherapy in adults with primary immune thrombocytopenia.

Previous observational studies suggest that rituximab may be useful in the treatment of primary immune thrombocytopenia (ITP). This randomized trial investigated rituximab efficacy in previously untreated adult ITP patients with a platelet count of 20 x 10(9)/L or less. One hundred three patients were randomly assigned to receive 40 mg/d dexamethasone for 4 days with or without 375 mg/m(2) rituximab weekly for 4 weeks. Patients who were refractory to dexamethasone alone received salvage therapy with dexamethasone plus rituximab. Sustained response (ie, platelet count > or = 50 x 10(9)/L at month 6 after treatment initiation), evaluable in 101 patients, was greater in patients treated with dexamethasone plus rituximab (n = 49) than in those treated with dexamethasone alone (n = 52; 63% vs 36%, P = .004, 95% confidence interval [95% CI], 0.079-0.455). Patients in the experimental arm showed increased incidences of grade 3 to 4 adverse events (10% vs 2%, P = .082, 95% CI, -0.010 to 0.175), but incidences of serious adverse events were similar in both arms (6% vs 2%, P = .284, 95% CI, -0.035 to 0.119). Dexamethasone plus rituximab was an effective salvage therapy in 56% of patients refractory to dexamethasone. The combination of dexamethasone and rituximab improved platelet counts compared with dexamethasone alone. Thus, combination therapy may represent an effective treatment option before splenectomy. This study is registered at http://clinicaltrials.gov as NCT00770562.

Clinical presentation, outcome and risk factors of late-onset non-infectious pulmonary complications after allogeneic stem cell transplantation.

The term late-onset non-infectious pulmonary complications (LONIPCs) has been used to refer to events occurring later than 3 months after allogeneic hematopoietic stem transplant (HSCT), such as bronchiolitis obliterans, bronchiolitis obliterans with organizing pneumonia, and lymphocytic or idiopathic interstitial pneumonia. The incidence of LONIPCs varies widely, ranging between 10% and 26%. Median time for LONIPC development is about 8-12 months after HSCT. Clinical symptoms may be insidious and non specific at the beginning and can be present in different types of infections. The diagnosis is made on the basis of thoracic high-resolution computed tomography and pulmonary function tests (PFT). It usually requires that standard cultures for infective agents on bronchoalveolar lavage are negative and is confirmed by transbronchial or lung biopsy, whenever possible. Total body irradiation and high doses of drugs used in the conditioning regimens, HLA disparity between donor and recipient, and chronic graft-versus-host disease (GVHD) are the main risk factors for LONIPCs. Since patients with LONIPCs have an increased risk of mortality because of infections or respiratory failure, pre- and post-transplant PFTs are strongly recommended in order to timely identify affected patients. The administration of antithymocyte globulin before unrelated donor transplants and slow taper of cyclosporine after transplant have been shown to prevent chronic GVHD and, therefore, the occurrence of LONIPCs.

Lower dose rituximab is active in adults patients with idiopathic thrombocytopenic purpura.

Rituximab 375 mg/m(2) weekly for four weeks has significant activity in patients with immune thrombocytopenia. We evaluated the activity of lower dose rituximab (100 mg iv weekly for 4 weeks) in 28 adults with idiopathic thrombocytopenic purpura. Overall (platelet count > 50 x 10(9)/L) and complete responses (platelet count > 100 x 10(9)/L) were achieved in 21/28 (75%) and 12/28 (43%) patients respectively. The median time to response and time to complete response were 31 and 44 days respectively. After a median follow-up of 11 months (range 3-18), 7/21 (33%) patients relapsed and 3 needed further treatments. In patients with idiopathic thrombocytopenic purpura, lower dose rituximab seems to show similar activity to standard dose.