Alternative graft sources, [umbilical cord blood (UCB), matched unrelated donors (MUD), or mismatched unrelated donors (MMUD)] enable patients without a matched sibling donor to receive potentially curative hematopoietic cell transplantation (HCT). Retrospective studies demonstrate comparable outcomes among different graft sources. However, the risk and types of infections have not been compared among graft sources. Such information may influence the choice of a particular graft source. We compared the incidence of bacterial, viral, and fungal infections in 1,781 adults with acute leukemia who received alternative donor HCT (UCB = 568, MUD = 930, MMUD = 283) between 2008 and 2011. The incidence of bacterial infection at one year was 72%, 59%, and 65% (p<0.0001) for UCB, MUD and MMUD, respectively. Incidence of viral infection at one year was 68%, 45%, 53% (p<0.0001) for UCB, MUD, and MMUD respectively. In multivariable analysis, bacterial, fungal, and viral infections were more common after either UCB or MMUD than MUD, (p<0.0001). Bacterial and viral, but not fungal, infections were more common after UCB than MMUD (p=0.0009 and <0.0001, respectively). The presence of viral infection was not associated with an increased mortality. Overall survival (OS) was comparable among UCB and MMUD patients with Karnofsky performance status (KPS) ≥90%, but was inferior for UCB for patients with KPS < 90%. Bacterial and fungal infections were associated with poorer OS. Future strategies focusing on infection prevention and treatment are indicated to improve HCT outcomes.

Bacterial bloodstream infections (BSI) cause significant transplant-related morbidity and mortality following allogeneic hematopoietic cell transplantation (allo-HCT). This manuscript reviews the risk factors for and the bacterial pathogens causing BSIs in allo-HCT recipients in the contemporary transplant period. In addition, it offers insight into emerging resistant pathogens and reviews clinical management considerations to treat and strategies to prevent BSIs in allo-HCT patients.

We identified CD22 expression on a blastic plasmacytoid dendritic cell (pDC) neoplasm presenting as a leukemia in a child. CD22 expression, as determined by the antibody s-HCL-1, was also noted on the neoplastic cells from three additional patients with blastic pDC tumors identified at our institution. Subsequently we determined that peripheral blood pDCs react with the s-HCL-1 antibody demonstrating that normal pDCs express CD22. Evaluation of five additional anti-CD22 antibodies indicated that staining of pDCs with these reagents was poor except for s-HCL-1. Therefore, the detection of CD22 on pDCs is best demonstrated with the use of this specific antibody clone. All anti-CD22 antibodies stained conventional DCs. We also evaluated the reactivity of the anti-CD22 antibodies with basophils and noted that the pattern of staining was similar to that seen with pDCs. The studies demonstrate that normal DCs and pDC neoplasms express CD22, and highlight clone specific differences in anti-CD22 antibody reactivity patterns on pDCs and basophils. q

Patients with hematologic malignancies and recipients of hematopoietic cell transplantation (HCT) are more likely to experience severe coronavirus disease 2019 (COVID-19) and have a higher risk of morbidity and mortality after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Compared to the general population, these patients have suboptimal humoral responses to COVID-19 vaccines and subsequently increased risk for breakthrough infections, underscoring the need for additional therapies, including pre- and post-exposure prophylaxis, to attenuate clinical progression to severe COVID-19. Therapies for COVID-19 are mostly available for adults and in the inpatient and outpatient settings. Selection and administration of the best treatment options are based on host factors; virus factors, including circulating SARS-CoV-2 variants; and therapeutic considerations, including the clinical efficacy, availability, and practicality of treatment and its associated side effects, including drug-drug interactions. In this paper, we discuss how we approach managing COVID-19 in patients with hematologic malignancies and recipients of HCT and cell therapy.