Are any specific respiratory viruses more severe than others in recipients of allogeneic stem cell transplantation? A focus on lower respiratory tract disease.

In the general population, influenza virus, respiratory syncytial virus, and SARS-CoV-2 are considered the most severe community-acquired respiratory viruses (CARVs). However, allogeneic stem cell transplant (allo-SCT) recipients may also face severe courses from other CARVs. This retrospective study compared outcomes of various CARV lower respiratory tract diseases (LRTD) in 235 adult allo-SCT recipients, excluding co-infection episodes. We included 235 adults allo-SCT recipients experiencing 353 CARV LRTD consecutive episodes (130 rhinovirus, 63 respiratory syncytial virus, 43 influenza, 43 human parainfluenza virus, 23 human metapneumovirus, 19 Omicron SARS-CoV-2, 17 common coronavirus, 10 adenovirus and 5 human bocavirus) between December 2013 and June 2023. Day 100 overall survival ranged from 78% to 90% without significant differences among CARV types. Multivariable analysis of day 100 all-cause mortality identified corticosteroid use of >1 to <30 mg/d [Hazard ratio (HR) 2.45, p = 0.02) and ≥30 mg/d (HR 2.20, p = 0.015) along with absolute lymphocyte count <0.2 × 109/L (HR 5.82, p < 0.001) and number of CARV episodes as a continuous variable per one episode increase (HR 0.48, p = 0.001) as independent risk factors for all-cause mortality. Degree of immunosuppression, rather than intrinsic CARV virulence, has the most significant impact on mortality in allo-SCT recipients with CARV-LRTD.

Outcome of Human Parainfluenza Virus infection in allogeneic stem cell transplantation recipients: possible impact of ribavirin therapy.

BACKGROUND: This retrospective study focused on analyzing community-acquired respiratory virus (CARV) infections, in particular human parainfluenza virus (hPIV) after allogeneic stem cell transplant (allo-SCT) in adults recipients. It aimed to assess the impact of ribavirin treatment, clinical characteristics, and risk factors associated with lower respiratory tract disease (LRTD) progression and all-cause mortality. PATIENTS AND METHODS: The study included 230 allo-SCT recipients diagnosed with hPIV between December 2013 and June 2023. Risk factors for the development of LRTD, disease severity, and mortality were analyzed. Ribavirin treatment was administered at physician discretion in 61 out of 230 cases (27%). RESULTS: Risk factors for LRTD progression in multivariate analysis were corticosteroids > 30 mg/day (Odds ratio (OR) 3.5, 95% Confidence Interval (C.I.) 1.3-9.4, p = 0.013), fever at the time of hPIV detection (OR 3.89, 95% C.I. 1.84-8.2, p < 0.001), and absolute lymphocyte count (ALC) < 0.2 × 109/L (OR 4.1, 95% C.I. 1.42-11.9, p = 0.009). In addition, the study found that ribavirin therapy significantly reduced progression to LRTD [OR 0.19, 95% C.I. 0.05-0.75, p = 0.018]. Co-infections (OR 5.7, 95% C.I. 1.4-23.5, p = 0.015) and ALC < 0.2 × 109/L (OR 17.7, 95% C.I. 3.6-87.1, p < 0.001) were independently associated with higher day + 100 after hPIV detection all-cause mortality. There were no significant differences in all-cause mortality and infectious mortality at day + 100 between the treated and untreated groups. CONCLUSION: ALC, corticosteroids, and fever increased the risk for progression to LRTD while ribavirin decreased the risk. However, mortality was associated with ALC and co-infections. This study supports further research of ribavirin therapy for hPIV in the allo-HSCT setting.

Efficacy of CAR T-Cell Therapy is Not Impaired by Previous Bispecific Antibody Treatment in Large B-Cell Lymphoma.

In this retrospective study, CAR T-cells remained effective in relapsed/refractory LBCL patients after prior exposure to bispecific antibodies (BsAbs) targeting different antigens. These results are relevant to clinical practice, particularly given the increasing use of BsAbs in earlier treatment lines.

Immune reconstitution after single-unit umbilical cord blood transplantation using anti-thymoglobulin and myeloablative conditioning in adults with hematological malignancies.

This study aimed to investigate the kinetics of immune recovery following umbilical cord blood transplantation (UCBT) in adults who received a myeloablative conditioning (MAC) regimen and antithymocyte globulin (ATG). While the immune recovery kinetics has been extensively studied in pediatric UCBT recipients, limited data exist for adults. We conducted a comprehensive analysis of 221 consecutive adult patients who underwent UCBT with MAC and ATG at a single institution. Our objective was to evaluate the influence of patient, disease, and transplant factors, along with acute graft-versus-host disease (aGVHD), on immune reconstitution and overall survival. Our findings confirm a delayed recovery of T cells, while B and NK cell reconstitution exhibited rapid progress, with NK cell counts reaching normal levels within 3 months post-transplantation and B cells within 6 months. Within CD3+ T cells, CD8+ T cells also experienced a delayed recovery (12 months), but to a lesser extent compared to CD4+ T cells (18 months). Delayed immune recovery of T-cell subsets was associated with the development of aGVHD grade II-IV, older age, CMV negativity, and a female donor. Patients with lymphoproliferative diseases showed slower NK cell recovery. Our study demonstrates that adult patients undergoing MAC with ATG and receiving a single unit UCBT for hematologic malignancies experienced rapid reconstitution of NK and B cells. However, T cell recovery, particularly CD4+ T cells, was significantly delayed. To enhance T cell recovery, it may be crucial to consider UCB units with higher cellularity and optimize ATG doses in conditioning.

Development and characterization of a cell donor registry for virus-specific T cell manufacture in a blood bank.

Adoptive cell therapy using virus-specific T cells (VST) is a strategy for treating common opportunistic viral infections after transplantation, particularly when these infections do not resolve through antiviral drug therapy. The availability of third-party healthy donors allows for the immediate use of cells for allogeneic therapy in cases where patients lack an appropriate donor. Here, we present the creation of a cell donor registry of human leukocyte antigen (HLA)-typed blood donors, REDOCEL, a strategic initiative to ensure the availability of compatible cells for donation when needed. Currently, the registry consists of 597 healthy donors with a median age of 29 years, 54% of whom are women. The most represented blood groups were A positive and O positive, with 36.52% and 34.51%, respectively. Also, donors were screened for cytomegalovirus (CMV) and Epstein-Barr virus (EBV). Almost 65% of donors were CMV-seropositive, while less than 5% were EBV-seronegative. Of the CMV-seropositive donors, 98% were also EBV-seropositive. High-resolution HLA-A, -B, -C, -DRB1 and -DQB1 allele and haplotype frequencies were determined in the registry. Prevalent HLA alleles and haplotypes were well represented to ensure donor-recipient HLA-matching, including alleles reported to present viral immunodominant epitopes. Since the functional establishment of REDOCEL, in May 2019, 87 effective donations have been collected, and the effective availability of donors with the first call has been greater than 75%. Thus, almost 89% of patients receiving an effective donation had available at least 5/10 HLA-matched cell donors (HLA-A, -B, -C, -DRB1, and -DQB1). To summarize, based on our experience, a cell donor registry from previously HLA-typed blood donors is a useful tool for facilitating access to VST therapy.

Cytomegalovirus-driven early-onset lymphocytosis in hematopoietic allogeneic transplant mimicking a T-cell lymphoma progression.

Hepatosplenic T-cell lymphoma (HSTCL) is an uncommon and highly aggressive subtype of peripheral T-cell lymphoma characterized by liver, spleen, and bone marrow involvement. Allogeneic hematopoietic stem cell transplantation (alloHSCT) is the only curative treatment for HSTCL, but it carries a significant risk of relapse. Cytomegalovirus (CMV) reactivation is a frequent complication after alloHSCT, particularly in patients undergoing lymphocyte-toxic therapies. A 27-year-old man diagnosed with HSTCL underwent an alloHSCT with active disease after six lines of therapy. A CMV reactivation was successfully treated with foscarnet. A sudden reappearance of symptomatic lymphocytosis (15,550/µL) by day +20, prior to engraftment, raised suspicion of disease progression. A comprehensive diagnostic work-up revealed an oligoclonal expansion of donor lymphocytes along with complete donor chimerism, leading to an alternative diagnosis of a CMV-driven T-cell expansion. This was confirmed by an in vitro assay testing T-cell specificity against CMV. The patient achieved both complete response and complete donor chimerism despite persisting lymphocytosis, but ultimately relapsed. This case highlights the importance of diagnostic tools in understanding disease progression and guiding treatment decisions.

Torque Teno Virus plasma DNA load: a novel prognostic biomarker in CAR-T therapy.

Torque Teno Virus (TTV) is a single-stranded circular DNA virus which has been identified as a surrogate marker of immune competence in transplantation. In this study we investigated the dynamics of plasma TTV DNAemia in 79 adult patients undergoing chimeric antigen receptor T-cell (CAR-T) therapy for relapsed or refractory large B-cell lymphoma, also evaluating the impact of TTV on immunotoxicities, response and survival outcomes. After lymphodepleting therapy, TTV DNA load was found to decrease slightly until reaching nadir around day 10, after which it increased steadily until reaching maximum load around day 90. TTV DNA load < 4.05 log10 copies/ml at immune effector cell-associated neurotoxicity syndrome (ICANS) onset identified patients at risk of progressing to severe forms of ICANS (OR 16.68, P = 0.048). Finally, patients who experienced falling or stable TTV DNA load between lymphodepletion and CAR-T infusion had better progression-free survival than those with ascending TTV DNA load (HR 0.31, P = 0.006). These findings suggest that TTV monitoring could serve as a surrogate marker of immune competence, enabling predictions of CAR-T efficacy and toxicity. This could pave the way for the development of TTV-guided therapeutic strategies that modulate clinical patient management based on plasma TTV load, similar to suggested strategies in solid organ transplant recipients.

Remdesivir or Nirmatrelvir/Ritonavir Therapy for Omicron SARS-CoV-2 Infection in Hematological Patients and Cell Therapy Recipients.

BACKGROUND: Scarce data exist that analyze the outcomes of hematological patients with SARS-CoV-2 infection during the Omicron variant period who received treatment with remdesivir or nirmatrelvir/ritonavir. METHODS: This study aims to address this issue by using a retrospective observational registry, created by the Spanish Hematopoietic Stem Cell Transplantation and Cell Therapy Group, spanning from 27 December 2021 to 30 April 2023. RESULTS: This study included 466 patients, 243 (52%) who were treated with remdesivir and 223 (48%) with nirmatrelvir/ritonavir. Nirmatrelvir/ritonavir was primarily used for mild cases, resulting in a lower COVID-19-related mortality rate (1.3%), while remdesivir was preferred for moderate to severe cases (40%), exhibiting a higher mortality rate (9%). A multivariate analysis in the remdesivir cohort showed that male gender (odds ratio (OR) 0.35, p = 0.042) correlated with a lower mortality risk, while corticosteroid use (OR 9.4, p < 0.001) and co-infection (OR 2.8, p = 0.047) were linked to a higher mortality risk. Prolonged virus shedding was common, with 52% of patients shedding the virus for more than 25 days. In patients treated with remdesivir, factors associated with prolonged shedding included B-cell malignancy as well as underlying disease, severe disease, a later onset of and shorter duration of remdesivir treatment and a higher baseline viral load. Nirmatrelvir/ritonavir demonstrated a comparable safety profile to remdesivir, despite a higher risk of drug interactions. CONCLUSIONS: Nirmatrelvir/ritonavir proved to be a safe and effective option for treating mild cases in the outpatient setting, while remdesivir was preferred for severe cases, where corticosteroids and co-infection significantly predicted worse outcomes. Despite antiviral therapy, prolonged shedding remains a matter of concern.

In vitro assessment of the combined effect of letermovir and sirolimus on cytomegalovirus replication / Evaluación in vitro del efecto combinado de letermovir y sirolimus en la replicación de citomegalovirus

Introduction. Letermovir (LMV) is used for prophy laxis of cytomegalovirus (CMV) reactivation and end-or gan disease in adult CMV-seropositive allogeneic hemato poietic stem cell transplant recipients (allo-HSCT). In turn, sirolimus (SLM) which displays in vitro anti-CMV activity, is frequently employed for prophylaxis of Graft vs. Host disease in allo-HSCT. Here, we aimed at assessing whether LMV and SLM used in combination may act synergistically in vitro on inhibiting CMV replication. Material and methods. The antiviral activity of LMV and SLM alone or in combination was evaluated by a checkerboard assay, using ARPE-19 cells infected with CMV strain BADrUL131-Y. LMV and SLM were used at con centrations ranging from 24 nM to 0.38 nM and 16 nM to 0.06 nM, respectively. Results. The mean EC50 for LMV and SLM was 2.44 nM (95% CI, 1.66-3.60) and 1.40 nM (95% CI, 0.41-4.74), re spective. LMV and SLM interaction yielded mainly additive effects over the range of concentrations tested. Conclusion. The additive nature of the combination of LMV and SLM against CMV may have relevant clini cal implications in management of CMV infection in al lo-HSCT recipients undergoing prophylaxis with LMV (AU)

Introducción. Letermovir (LMV) se utiliza para la pro filaxis de la reactivación de la infección y de la enfermedad orgánica por citomegalovirus (CMV) en adultos receptores de trasplante alogénico de células madre hematopoyéticas (alo TPH) en pacientes seropositivos para CMV. A su vez, sirolimus (SLM), que muestra actividad anti-CMV in vitro, se usa con fre cuencia para la profilaxis de la enfermedad de injerto contra huésped en alo-TPH. Nuestro objetivo fue evaluar si LMV y SLM utilizados en combinación pueden actuar sinérgicamente in vi tro en inhibir la replicación del CMV. Material y métodos. La actividad antiviral de LMV y SLM individualmente o en combinación se evaluó mediante un en sayo de tablero de ajedrez, utilizando células ARPE-19 infec tadas con la cepa BADrUL131-Y de CMV. Se utilizaron LMV y SLM en concentraciones que variaron entre 24 nM y 0,38 nM y entre 16 nM y 0,06 nM, respectivamente. Resultados. La EC50 media para LMV y SLM fue de 2,44 nM (IC del 95 %, 1,66-3,60) y 1,40 nM (IC del 95 %, 0,41-4,74), respectivamente. La interacción LMV y SLM produjo principal mente efectos aditivos en el rango de concentraciones ensa yadas. Conclusión. La naturaleza aditiva de la combinación de LMV y SLM frente a CMV puede tener implicaciones clínicas re levantes en el tratamiento de la infección por CMV en alo-TPH que reciben profilaxis con LMV (AU)

Rationale for combined therapies in severe-to-critical COVID-19 patients.

An unprecedented global social and economic impact as well as a significant number of fatalities have been brought on by the coronavirus disease 2019 (COVID-19), produced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Acute SARS-CoV-2 infection can, in certain situations, cause immunological abnormalities, leading to an anomalous innate and adaptive immune response. While most patients only experience mild symptoms and recover without the need for mechanical ventilation, a substantial percentage of those who are affected develop severe respiratory illness, which can be fatal. The absence of effective therapies when disease progresses to a very severe condition coupled with the incomplete understanding of COVID-19's pathogenesis triggers the need to develop innovative therapeutic approaches for patients at high risk of mortality. As a result, we investigate the potential contribution of promising combinatorial cell therapy to prevent death in critical patients.

Real-World Experience in Extracorporeal Photopheresis for Adults with Graft-versus-Host Disease.

Extracorporeal photopheresis (ECP) has shown efficacy in treating graft-versus-host disease (GVHD). We aim to summarize eight years of real-world experience with off-line ECP in our institution, in order to validate this treatment schedule and analyze predictive factors. All consecutive adult patients with steroid-dependent or steroid-refractory GVHD undergoing off-line ECP were included in this single-center retrospective study. ECP was performed with a Spectra Optia device, processing 1 total blood volume, at a twice-weekly frequency for acute GVHD (aGVHD) and once weekly for chronic GVHD (cGVHD), and tapered individually according to clinical response. The cumulative incidence of response, including complete response (CR) and partial response (PR), were compared among patients grouped by different baseline, apheresis, and disease characteristics. Between January 2015 and May 2022, a total of 1382 ECP procedures were proposed for 82 patients. No incidents were reported in 97% of the ECP sessions. GVHD responded in 78% of patients (aGVHD: 57% CR and 4% PR; cGVHD, 39% CR and 48% PR). Overall survival was statistically greater for aGVHD patients who responded to ECP compared to those who did not respond (67.5% versus 26% at 1 year; P = 0.037). Severity was an independent predictor of response in aGVHD, whereas the absence of mouth involvement and lower lymphocyte counts in the apheresis product correlated with a higher response in cGVHD. Our findings support the effectiveness of this treatment schedule for GVHD. Further investigation is required to identify ECP-specific predictive factors, given that findings are not homogeneous across studies.

Respiratory virus infections after allogeneic stem cell transplantation: Current understanding, knowledge gaps, and recent advances.

Before the COVID-19 pandemic, common community-acquired seasonal respiratory viruses (CARVs) were a significant threat to the health and well-being of allogeneic hematopoietic cell transplant (allo-HCT) recipients, often resulting in severe illness and even death. The pandemic has further highlighted the significant risk that immunosuppressed patients, including allo-HCT recipients, face when infected with SARS-CoV-2. As preventive transmission measures are relaxed and CARVs circulate again among the community, including in allo-HSCT recipients, it is crucial to understand the current state of knowledge, gaps, and recent advances regarding CARV infection in allo-HCT recipients. Urgent research is needed to identify seasonal respiratory viruses as potential drivers for future pandemics.

Reduced Incidence of Neurologic Complications after Allogeneic Hematopoietic Stem Cell Transplantation with Calcineurin-Free Graft-versus-Host Disease Prophylaxis.

Calcineurin inhibitors (CNIs), including cyclosporine and tacrolimus, are frequently associated with neurologic complications after allogeneic hematopoietic stem cell transplantation (HSCT). However, there is a lack of studies comparing the incidence and characteristics of neurologic complications in patients undergoing HSCT based on CNI-free or CNI-based GVHD prophylaxis. This retrospective single-center study analyzed the neurologic complications in 2 cohorts of patients undergoing HSCT with either CNI-based GVHD prophylaxis (n = 523) or CNI-free prophylaxis with post-transplantation cyclophosphamide, sirolimus, and mycophenolate mofetil (n = 371). The latter cohort included older patients and received more reduced-intensity conditioning and transplants from matched unrelated and haploidentical donors. The 2-year cumulative incidence of neurologic complications was significantly lower in the CNI-free cohort (6.9% versus 11.9%; P = .016), and GVHD prophylaxis was the sole statistically significant variable in multivariate analysis (hazard ratio, 2.2; 95% confidence interval [CI], .25 to 3.13; P = .0017). The distribution of neurologic types was similar in the 2 cohorts, with encephalopathy the most prevalent complication, except for headaches and myopathy, which decreased equally from 15% in the CNI-based cohort to 4% in the CNI-free cohort. Neurologic complications had negative impacts on mortality and survival rates, with a significantly higher 2-year cumulative incidence of nonrelapse mortality (NRM) (44% [95% CI, 34% to 54%] versus 16% [95% CI, 13% to 18%]; P < .0001) and inferior overall survival (66% [95% CI, 62% to 69%] versus 46% [95% CI, 37% to 58%]; P < .0001) in patients with neurologic complications. This study suggests that CNI-free GVHD prophylaxis with post-transplantation cyclophosphamide, sirolimus, and mycophenolate mofetil may reduce not only the incidence of GVHD incidence, but also the rates of neurologic complications and NRM, leading to improved survival outcomes in patients undergoing HSCT.

High Rate of Inappropriate Antibiotics in Patients with Hematologic Malignancies and Pseudomonas aeruginosa Bacteremia following International Guideline Recommendations.

Optimal coverage of Pseudomonas aeruginosa is challenging in febrile neutropenic patients due to a progressive increase in antibiotic resistance worldwide. We aimed to detail current rates of resistance to antibiotics recommended by international guidelines for P. aeruginosa isolated from bloodstream infections (BSI) in patients with hematologic malignancies. Secondarily, we aimed to describe how many patients received inappropriate empirical antibiotic treatment (IEAT) and its impact on mortality. We conducted a retrospective, multicenter cohort study of the last 20 BSI episodes caused by P. aeruginosa in patients with hematologic malignancies from across 14 university hospitals in Spain. Of the 280 patients with hematologic malignancies and BSI caused by P. aeruginosa, 101 (36%) had strains resistant to at least one of the ß-lactam antibiotics recommended in international guidelines, namely, cefepime, piperacillin-tazobactam, and meropenem. Additionally, 21.1% and 11.4% of the strains met criteria for MDR and XDR P. aeruginosa, respectively. Even if international guidelines were followed in most cases, 47 (16.8%) patients received IEAT and 66 (23.6%) received inappropriate ß-lactam empirical antibiotic treatment. Thirty-day mortality was 27.1%. In the multivariate analysis, pulmonary source (OR 2.22, 95% CI 1.14 to 4.34) and IEAT (OR 2.67, 95% CI 1.37 to 5.23) were factors independently associated with increased mortality. We concluded that P. aeruginosa-causing BSI in patients with hematologic malignancies is commonly resistant to antibiotics recommended in international guidelines, which is associated with frequent IEAT and higher mortality. New therapeutic strategies are needed. IMPORTANCE Bloodstream infection (BSI) caused by P. aeruginosa is related with an elevated morbidity and mortality in neutropenic patients. For this reason, optimal antipseudomonal coverage has been the basis of all historical recommendations in the empirical treatment of febrile neutropenia. However, in recent years the emergence of multiple types of antibiotic resistances has posed a challenge in treating infections caused by this microorganism. In our study we postulated that P. aeruginosa-causing BSI in patients with hematologic malignancies is commonly resistant to antibiotics recommended in international guidelines. This observation is associated with frequent IEAT and increased mortality. Consequently, there is a need for a new therapeutic strategy.

Features of cytomegalovirus DNAemia and virus-specific T-cell responses in allogeneic hematopoietic stem-cell transplant recipients during prophylaxis with letermovir.

BACKGROUND: There is scarce information on the natural kinetics of cytomegalovirus (CMV) DNAemia and dynamics of CMV-specific T-cell reconstitution in allogeneic hematopoietic transplant recipients (allo-HSCT) undergoing letermovir (LMV) prophylaxis. METHODS: Twelve adult CMV-seropositive high-risk recipients (median age, 53 years; 9 males/3 females) undergoing LMV prophylaxis and 13 non-LMV allo-HSCT controls (median age, 58 years; 7 males/6 females) were included. CMV DNAemia in plasma was monitored by real-time polymerase chain reaction. Preemptive antiviral therapy (PET) was administered upon detection of ≥1500 IU/ml. CMV-specific interferon-gamma (IFN-γ)-producing CD8+ and CD4+ T cells were enumerated by flow cytometry around days +30, +60, and +90 after allo-HSCT. Ex vivo experiments assessing of the potential effect of LMV on CMV-specific T-cell expansion in a single CMV-seropositive donor were also conducted. RESULTS: Five LMV patients (41.6%) developed CMV DNAemia that cleared spontaneously. Four patients (33.3%) developed CMV DNAemia after LMV cessation, of which two required PET. Nine non-LMV patients (69.2%) developed CMV DNAemia (five required PET). The percentage of LMV and non-LMV patients exhibiting detectable CMV-specific T-cell responses was comparable (7/10 vs. 10/13; p = .71). Nevertheless, median CMV-specific CD4+ and CD8+ T-cell counts were lower in LMV patients by days +60 (p = .006 and .02, respectively) and +90 (p = .08 and .02). Ex vivo, CMV-specific CD8+ T cells expanded to the same level either in the presence (19.8%) or in the absence of LMV (20.6%). CONCLUSIONS: In our series, episodes of CMV DNAemia in LMV patients cleared spontaneously. A diminished degree of CMV-specific T-cell reconstitution in LMV patients compared to non-LMV patients was observed.

One-year breakthrough SARS-CoV-2 infection and correlates of protection in fully vaccinated hematological patients.

The long-term clinical efficacy of SARS-CoV-2 vaccines according to antibody response in immunosuppressed patients such as hematological patients has been little explored. A prospective multicenter registry-based cohort study conducted from December 2020 to July 2022 by the Spanish Transplant and Cell Therapy group, was used to analyze the relationship of antibody response over time after full vaccination (at 3-6 weeks, 3, 6 and 12 months) (2 doses) and of booster doses with breakthrough SARS-CoV-2 infection in 1551 patients with hematological disorders. At a median follow-up of 388 days after complete immunization, 266 out of 1551 (17%) developed breakthrough SARS-CoV-2 infection at median of 86 days (range 7-391) after full vaccination. The cumulative incidence was 18% [95% confidence interval (C.I.), 16-20%]. Multivariate analysis identified higher incidence in chronic lymphocytic leukemia patients (29%) and with the use of corticosteroids (24.5%), whereas female sex (15.5%) and more than 1 year after last therapy (14%) were associated with a lower incidence (p < 0.05 for all comparisons). Median antibody titers at different time points were significantly lower in breakthrough cases than in non-cases. A serological titer cut-off of 250 BAU/mL was predictive of breakthrough infection and its severity. SARS-CoV-2 infection-related mortality was encouragingly low (1.9%) in our series. Our study describes the incidence of and risk factors for COVID-19 breakthrough infections during the initial vaccination and booster doses in the 2021 to mid-2022 period. The level of antibody titers at any time after 2-dose vaccination is strongly linked with protection against both breakthrough infection and severe disease, even with the Omicron SARS-CoV-2 variant.

Impact of Post-Transplantation Cyclophosphamide on Transfusion Requirements in HLA-Matched Sibling Peripheral Blood Stem Cell Transplantation.

Post-transplantation cyclophosphamide (PTCy)-based graft-versus-host disease (GVHD) prophylaxis is being increasingly used in allogeneic hematopoietic stem cell transplantation (allo-HSCT) from HLA-matched related donors (MRDs); however, information regarding the transfusion needs in this setting is lacking. This study compared RBC and platelet units transfused and time to transfusion independence according to the GVHD prophylaxis regimen in MRD HSCT. We performed a matched-pair analysis comparing the transfusion requirements and the clinical outcomes of patients who underwent MRD peripheral blood HSCT using PTCy between January 2017 and June 2021 (n = 100) with historical MRD HSCTs using standard cyclosporine A (CsA)-based prophylaxis (n = 100). Neutrophil engraftment was significantly delayed in the PTCy group compared with the CsA group (16 days versus 13 days; P = .003). PTCy was associated with increased RBC (median, 5 units versus 4 units; P = .04) and platelet (median, 6 units versus 3 units; P = .01) transfusion requirements during the first 30 days after transplantation. The proportion of patients requiring platelet transfusion during days 31 to 90 after transplantation was also higher in the PTCy group (55% versus 25%; P < .0001). In multivariate analysis, PTCy was associated with delayed RBC and platelet transfusion independence (hazard ratio, .61 [P = .007] and .51 [P < .0001], respectively). The cumulative incidence (CuI) of BK polyomavirus-associated hemorrhagic cystitis grade ≥2 at 100 days was higher in the PTCy group (34% versus 12%; P < .0001); however, the PTCy group had lower rates of grade II-IV acute GVHD (100-day CuI, 57% versus 23%; P < .0001) and moderate to severe chronic GVHD (1-year CuI, 49% versus 28%; P = .003), as well as better 2-year overall survival (74% versus 56%; P = .01). Our study shows that although PTCy increases the transfusion burden in MRD HSCT, it is associated with a low incidence of severe GVHD and with encouraging survival outcomes.

T Cell-Depleted Peripheral Blood versus Unmanipulated Bone Marrow in Matched Sibling Transplantation for Aplastic Anemia.

Bone marrow (BM) is the recommended stem cell source for hematopoietic stem cell transplantation (HSCT) from matched sibling donors (MSDs) in patients with severe aplastic anemia (SAA) for its superior survival and graft-versus-host disease (GVHD) outcomes compared to recipients of unmanipulated peripheral blood (PB) HSCT. Nevertheless, no studies comparing BM with ex vivo T cell-depleted (TCD) PB have been reported to date. The aim of the present study was to compare the transplantation outcomes of MSD HSCT recipients with SAA using PB (with partial ex vivo TCD targeted cell dose grafts) with those of MSD HSCT recipients with SAA using unmanipulated BM. We performed a matched-pair analysis of MSD-HSCT using TCD PB in a single institution with unmanipulated BM MSD-HSCT in the United States between 2013 and 2019 reported to the Center for International Blood and Marrow Transplant Research. We compared 23 recipients of TCD PB HSCT for SAA (cases) and 69 recipients of unmanipulated BM grafts (controls) matched for age, Karnofsky Performance Status, Hematopoietic Cell Transplantation-Specific Comorbidity Index, time from diagnosis to transplantation, and recipient cytomegalovirus serostatus. We found significantly faster neutrophil and platelet recovery in the TCD PB cohort (P < .001 and P = .03, respectively), as well as a lower incidence of grade II-IV acute GVHD (0% versus 17%; P = .05) and similar overall survival (96% versus 97% at 3 years; P = .8). Our study shows that TCD PB can be considered a safe source for MSD-HSCT in patients with SAA, with potential advantages in engraftment and GVHD that could challenge the standard with BM. These findings provide a basis for future research in a prospective controlled clinical trial.