Mycobacterium chelonae is a rare cause of chronic disseminated cutaneous infections in immunocompromised patients. Multidrug-resistant M. chelonae infections present a challenge for treatment, and prolonged antimicrobial courses lead to significant toxicities and further antimicrobial resistance. We report a case of refractory cutaneous disseminated M. chelonae infection in a patient with seronegative arthritis on immunotherapy with tofacitinib that was treated with combination antimicrobial, surgical, and single bacteriophage therapy with excellent clinical response. The patient developed neutralizing antibodies against the bacteriophage but continues to have stable improvement of disease with negative biopsies and no evidence of bacterial resistance to the phage.

CAR T-cell therapy has revolutionized the treatment of hematologic malignancies, although its use may be complicated by toxicities, including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and infections. Invasive fungal disease (IFD) has been reported after CAR T-cell therapy, but the incidence in the absence of antifungal prophylaxis is unknown. Optimal prophylaxis strategies are widely debated. We performed a single-center retrospective study of 280 adults receiving CD19 CAR T-cell therapy for non-Hodgkin lymphoma (NHL) from December 2017 through September 2021. Patients did not receive routine antiyeast or antimold prophylaxis. IFD was identified between day of cell infusion and last follow-up. Cumulative incidence functions were calculated at 100 days and 18 months based on time to IFD, using dates of IFD-free death, initiation of salvage treatment, and hematopoietic cell transplantation as competing risks. Eight patients (2.9%) developed IFD, including 3 Pneumocystis jirovecii pneumonia, 3 invasive mold infections (IMIs), and 2 invasive yeast infections (IYIs). The 100-day cumulative incidence of IFD accounting for competing risks was 1.8% (95% confidence interval [CI], 0.8% to 4.4%). Among the 280 patients, early toxicities including CRS (85%) and ICANS (55%) and late toxicities after day 30 including grades 3 and 4 neutropenia (41%) and low CD4 T-cell count (20%) were common. IFD was rare among patients who received CD19 CAR T-cell therapy for NHL in the absence of routine antifungal prophylaxis, despite frequent toxicities. These results suggest that, in settings with low institutional rates of IFD, routine antifungal prophylaxis may not be indicated.

The use of targeted biologic therapies for hematological malignancies has greatly expanded in recent years. These agents act upon specific molecular pathways in order to target malignant cells but frequently have broader effects involving both innate and adaptive immunity. Patients with hematological malignancies have unique risk factors for infection, including immune dysregulation related to their underlying disease and sequelae of prior treatment regimens. Determining the individual risk of infection related to any novel agent is challenging in this setting. Invasive fungal infections (IFIs) represent one of the most morbid infectious complications observed in hematological malignancy. In recent years, growing evidence suggests that certain small molecule inhibitors, such as BTK inhibitors and PI3K inhibitors, may cause an increased risk of IFI in certain patients. It is imperative to better understand the impact that novel targeted therapies might have on the development of IFIs in this high-risk patient population.

Infections are an important complication after B-cell maturation antigen (BCMA)–directed chimeric antigen receptor (CAR) T-cell therapy and risks may differ between the early and late periods. We evaluated infections in 99 adults who received a first BCMA–directed CAR T-cell therapy (commercial and investigational autologous BCMA CAR T-cell products at the recommended phase 2 dose) for relapsed/refractory multiple myeloma between November 2016 and May 2022. Infections were recorded until day 365, if patients experienced symptoms with a microbiologic diagnosis, or for symptomatic site-specific infections treated with antimicrobials. One-year cumulative incidence functions were calculated based on time to first respiratory infection using dates of infection-free death and receipt of additional antineoplastic therapies as competing risks. Secondary analysis evaluated risk factors for late respiratory infections using univariate and multivariable Cox regression models. Thirty-seven patients (37%) experienced 64 infectious events over the first year after BCMA–directed CAR T-cell therapy, with 42 early infectious events (days, 0-100), and 22 late infectious events (days, 101-365). Respiratory infections were the most common site-specific infection and the relative proportion of respiratory infections increased in the late period (31% of early events vs 77% of late events). On multivariable analysis, hypogammaglobulinemia (hazard ratio [HR], 6.06; P = .044) and diagnosis of an early respiratory viral infection (HR, 2.95; P = .048) were independent risk factors for late respiratory infection. Respiratory infections predominate after BCMA CAR T-cell therapy, particularly after day 100. Hypogammaglobulinemia and diagnosis of an early respiratory infection are risk factors for late respiratory infections that may be used to guide targeted preventive strategies.

Chimeric antigen receptor (CAR) T-cell therapy is a novel immunotherapy approved for the treatment of hematologic malignancies. This therapy leads to a variety of immunologic deficits that could place patients at risk for invasive fungal disease (IFD). Studies assessing IFD in this setting are limited by inconsistent definitions and heterogeneity in prophylaxis use, although the incidence of IFD after CAR T-cell therapy, particularly for lymphoma and myeloma, appears to be low. This review evaluates the incidence of IFD after CAR T-cell therapy, and discusses optimal approaches to prevention, highlighting areas that require further study as well as future applications of cellular therapy that may impact IFD risk. As the use of CAR T-cell therapy continues to expand for hematologic malignancies, solid tumors, and most recently to include non-oncologic diseases, understanding the risk for IFD in this uniquely immunosuppressed population is imperative to prevent morbidity and mortality.

Post-transplant cyclophosphamide (PTCy) is an effective strategy for graft-versus-host disease (GVHD) prophylaxis and is the standard of care for haploidentical hematopoietic cell transplantation (HCT). It is increasingly used for matched and mismatched unrelated donor (MUD/MMUD) HCT, but infections remain a concern. The objective of this study was to evaluate the characteristics and risk factors for infections in haploidentical and unrelated donor HCT recipients treated with PTCy-based GVHD prophylaxis. This single-center retrospective study examined 354 consecutive adults undergoing HCT with PTCy-based GVHD prophylaxis (161 MUD/MMUD; 193 haploidentical) between 2015 and 2022. Opportunistic infections (OIs) including cytomegalovirus (CMV), adenovirus (AdV), Epstein-Barr virus (EBV), and invasive fungal disease (IFD) were assessed from day 0 through day +365. The one-year cumulative incidence function of OIs and non-relapse mortality were calculated using dates of relapse and repeat HCT as competing risks. Secondary analysis evaluated risk factors for OIs and NRM using univariate and multivariable Cox regression models. Haploidentical HCT recipients had an increased risk of OIs compared to unrelated donor allograft recipients (39% haploidentical vs. 25% MUD/MMUD; HR 1.70; 95% CI 1.16 - 2.49; p=0.006). On multivariable analysis, haploidentical donor (HR 1.50; 95% CI 1.01 - 2.23; p=0.046), prior HCT (HR 1.99; 95% CI 1.29 - 3.09; p=0.002), and diagnosis of acute GVHD (HR 1.47; 95% CI 1.02 - 2.14; p=0.041) were associated with an increased risk of OIs. Non-relapse mortality within the first year was not significantly different between the two groups (HR 1.11; 95% CI 0.64 - 1.93; p=0.70). Overall, haploidentical donor was a significant risk factor for OIs in patients receiving PTCy, although one-year NRM was not different between haploidentical and MUD/MMUD HCT recipients. CMV and adenovirus infections were significantly increased amongst haploidentical HCT recipients, while the incidence of EBV infection and IFD was similar between the groups. Our findings may have implications for infection monitoring and prophylaxis in the setting of PTCy, particularly in haploidentical HCT recipients.