Purpose Clonal hematopoiesis of indeterminate potential (CHIP) occurs in the blood of approximately 20% of older persons. CHIP is linked to an increased risk of hematologic malignancies and of all-cause mortality; thus, the eligibility of stem-cell donors with CHIP is questionable. We comprehensively investigated how donor CHIP affects outcome of allogeneic hematopoietic stem-cell transplantation (HSCT). Methods We collected blood samples from 500 healthy, related HSCT donors (age ≥ 55 years) at the time of stem-cell donation for targeted sequencing with a 66-gene panel. The effect of donor CHIP was assessed on recipient outcomes, including graft-versus-host disease (GVHD), cumulative incidence of relapse/progression (CIR/P), and overall survival (OS). Results A total of 92 clonal mutations with a median variant allele frequency of 5.9% were identified in 80 (16.0%) of 500 donors. CHIP prevalence was higher in donors related to patients with myeloid compared with lymphoid malignancies (19.2% v 6.3%; P ≤ .001). In recipients allografted with donor CHIP, we found a high cumulative incidence of chronic GVHD (cGVHD; hazard ratio [HR], 1.73; 95% CI, 1.21 to 2.49; P = .003) and lower CIR/P (univariate: HR, 0.62; 95% CI, 0.40 to 0.97; P = .027; multivariate: HR, 0.63; 95% CI, 0.41 to 0.98; P = .042) but no effect on nonrelapse mortality. Serial quantification of 25 mutations showed engraftment of 24 of 25 clones and disproportionate expansion in half of them. Donor-cell leukemia was observed in two recipients. OS was not affected by donor CHIP status (HR, 0.88; 95% CI, 0.65 to 1.321; P = .434). Conclusion Allogeneic HSCT from donors with CHIP seems safe and results in similar survival in the setting of older, related donors. Future studies in younger and unrelated donors are warranted to extend these results. Confirmatory studies and mechanistic experiments are warranted to challenge the hypothesis that donor CHIP might foster cGVHD development and reduce relapse/progression risk.

While several studies have described the clinical course of patients with coronavirus disease 2019 (COVID-19), direct comparisons with patients with seasonal influenza are scarce. We compared 166 patients with COVID-19 diagnosed between February 27 and June 14, 2020, and 255 patients with seasonal influenza diagnosed during the 2017–18 season at the same hospital to describe common features and differences in clinical characteristics and course of disease. Patients with COVID-19 were younger (median age [IQR], 59 [45–71] vs 66 [52–77]; P < 0001) and had fewer comorbidities at baseline with a lower mean overall age-adjusted Charlson Comorbidity Index (mean [SD], 3.0 [2.6] vs 4.0 [2.7]; P < 0.001) than patients with seasonal influenza. COVID-19 patients had a longer duration of hospitalization (mean [SD], 25.9 days [26.6 days] vs 17.2 days [21.0 days]; P = 0.002), a more frequent need for oxygen therapy (101 [60.8%] vs 103 [40.4%]; P < 0.001) and invasive ventilation (52 [31.3%] vs 32 [12.5%]; P < 0.001) and were more frequently admitted to the intensive care unit (70 [42.2%] vs 51 [20.0%]; P < 0.001) than seasonal influenza patients. Among immunocompromised patients, those in the COVID-19 group had a higher hospital mortality compared to those in the seasonal influenza group (13 [33.3%] vs 8 [11.6%], P = 0.01). In conclusion, we show that COVID-19 patients were younger and had fewer baseline comorbidities than seasonal influenza patients but were at increased risk for severe illness. The high mortality observed in immunocompromised COVID-19 patients emphasizes the importance of protecting these patient groups from SARS-CoV-2 infection.

Summary Background Invasive fungal diseases remain a major cause of morbidity and mortality in cancer patients undergoing intensive cytotoxic therapy. The choice of the most appropriate antifungal treatment (AFT) depends on the fungal species suspected or identified, the patient's risk factors (eg length and depth of granulocytopenia) and the expected side effects. Objectives Since the last edition of recommendations for ‘Treatment of invasive fungal infections in cancer patients’ of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Medical Oncology (DGHO) in 2013, treatment strategies were gradually moving away from solely empirical therapy of presumed or possible invasive fungal diseases (IFDs) towards pre‐emptive therapy of probable IFD. Methods The guideline was prepared by German clinical experts for infections in cancer patients in a stepwise consensus process. MEDLINE was systematically searched for English‐language publications from January 1975 up to September 2019 using the key terms such as ‘invasive fungal infection’ and/or ‘invasive fungal disease’ and at least one of the following: antifungal agents, cancer, haematological malignancy, antifungal therapy, neutropenia, granulocytopenia, mycoses, aspergillosis, candidosis and mucormycosis. Results AFT of IFDs in cancer patients may include not only antifungal agents but also non‐pharmacologic treatment. In addition, the armamentarium of antifungals for treatment of IFDs has been broadened (eg licensing of isavuconazole). Additional antifungals are currently under investigation or in clinical trials. Conclusions Here, updated recommendations for the treatment of proven or probable IFDs are given. All recommendations including the levels of evidence are summarised in tables to give the reader rapid access to key information.

Hematologic and oncologic patients with chemo- or immunotherapy-related immunosuppression are at substantial risk for bacterial infections and Pneumocystis jirovecii pneumonia (PcP). As bacterial resistances are increasing worldwide and new research reshapes our understanding of the interactions between the human host and bacterial commensals, administration of antibacterial prophylaxis has become a matter of discussion. This guideline constitutes an update of the 2013 published guideline of the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Medical Oncology (DGHO). It gives an overview about current strategies for antibacterial prophylaxis in cancer patients while taking into account the impact of antibacterial prophylaxis on the human microbiome and resistance development. Current literature published from January 2012 to August 2020 was searched and evidence-based recommendations were developed by an expert panel. All recommendations were discussed and approved in a consensus conference of the AGIHO prior to publication. As a result, we present a comprehensive update and extension of our guideline for antibacterial and PcP prophylaxis in cancer patients.

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Anti T-cell lymphocyte globulin (ATLG) and post-transplant cyclophosphamide (PTCy) are now widely used strategies to prevent graft-versus-host disease after allogeneic stem cell transplantation. Data comparing immune reconstitution (IR) between ATLG and PTCy is scarce. This retrospective study conducted at the University Medical-Center Hamburg- Eppendorf (UKE) compares after myeloablative PBSC allogeneic stem cell transplant between PTCy (n=123) and ATLG (n=476). Detailed phenotypes of T, B natural killer (NK), natural killer T (NKT) cells were analyzed by multicolor flow at day 30, 100 and 180 posttransplant. Incidence of infections, viral reactivations graft-versus-host disease and relapse were collected. Neutrophil engraftment was significantly delayed in the PTCy group (median day 12 vs. 10, p < 0.001) with a high incidence of infection before day+100 in the PTCy arm but a higher EBV reactivation in the ATLG arm and comparable CMV reactivation. Overall incidence of acute GVHD was similar but moderate/severe chronic GVHD was more seen after PTCy (44% vs. 38%, p = 0.005). ATLG resulted in a faster reconstitution of CD8+ T-cells, NK cells, NKT cells, and γδT cells while CD4 T-cells and B-cells reconstituted faster after PTCy. Similar reconstitution was observed for T-regulatory cells and B-cells. NRM, relapse incidence, DFS, and overall survival did not differ significantly between both arms. Even though difference in IR have been translated into decreased incidence of infections and moderate/severe cGVHD in the ATLG group they had no impact on any of the other longterm outcomes. However, it remains undetermined which regimen is better as graft-versushost disease prophylaxis.

The curative potential of allogeneic hematopoietic cell transplantation (allo-HCT) in the treatment of acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) relies mainly on the graft-versus-leukemia effect. Relapse after allo-HCT occurs in a considerable proportion of patients and has a dismal prognosis, with still very limited curative potential. This review provides an overview of the established and evolving approaches to preventing or treating relapse of AML and MDS after allo-HCT, in the context of novel insight into the biology of relapse. Established prophylactic measures to prevent relapse include optimized conditioning and graft-versushost disease (GVHD) prophylaxis, as well as donor lymphocyte infusion (DLI) for high-risk patients; novel immunomodulatory interventions and maintenance approaches are still experimental. Improved diagnostics can detect persistent or recurring disease at a molecular level, enabling early preemptive interventions. Established options include hypomethylating agents and DLI. Standard treatments for hematologic relapse include chemotherapy, cessation of immunosuppressive treatment, and DLI. Experimental approaches include molecular targeted therapies, novel immunomodulatory treatments, and second allo-HCT. For all interventions, the potential risks, including occurrence of GVHD, must be weighed against the benefits individually in each patient. Concurrently, prevention and treatment of relapse after allo-HCT remain challenging and unmet medical needs.

The inclusion of mutation status improved risk stratification for newly diagnosed patients with chronic myelomonocytic leukemia (CMML). Stem cell transplantation is a potentially curative treatment option, and patient selection is critical because of relevant transplant-related morbidity and mortality. We aimed to evaluate the impact of mutation status together with clinical presentations on posttransplant outcome. Our study included 240 patients with a median follow-up of 5.5 years. A significant association with worse survival was identified for the presence of mutations in ASXL1 and/or NRAS. In multivariable analysis, ASXL1- and/or NRAS-mutated genotype (hazard ratio [HR], 1.63), marrow blasts &gt;2% (HR, 1.70), and increasing comorbidity index (continuous HR, 1.16) were independently associated with worse survival. A prognostic score (CMML transplant score) was developed, and the following points were assigned: 4 points for an ASXL1- and/or NRAS-mutated genotype or blasts &gt;2% and 1 point each for an increase of 1 in the comorbidity index. The CMML transplant score (range, 0-20) was predictive of survival and nonrelapse mortality (P &lt; .001 for both). Up to 5 risk groups were identified, showing 5-year survival of 81% for a score of 0 to 1, 49% for a score of 2 to 4, 43% for a score of 5 to 7, 31% for a score of 8 to 10, and 19% for a score &gt;10. The score retained performance after validation (concordance index, 0.68) and good accuracy after calibration. Predictions were superior compared with existing scores designed for the nontransplant setting, which resulted in significant risk reclassification. This CMML transplant score, which incorporated mutation and clinical information, was prognostic in patients specifically undergoing transplantation and may facilitate personalized counseling.