A Patient With Type 1 Diabetes and Acute Rhinosinusitis.

A 41-year-old with type 1 diabetes had generalized weakness, muffled voice, and slurred speech. Neck computed tomography showed soft-tissue gas in the nasopharynx and prevertebral fascia; examination of sinus mucosal samples identified numerous broad, nonseptate right-angled hyphae and fruiting bodies. What is the diagnosis and what would you do next?

Atypical pneumonia testing in transplant recipients.

BACKGROUND: The incidence of atypical pneumonia among immunocompromised patients is not well characterized. Establishing a diagnosis of atypical pneumonia is challenging as positive tests must be carefully interpreted. We aimed to assess the test positivity rate and incidence of atypical pneumonia in transplant recipients. METHODS: A retrospective cohort study was conducted at the Yale New Haven Health System in Connecticut. Adults with solid organ transplant, hematopoietic stem cell transplant (HSCT), or chimeric antigen receptor T-cell, who underwent testing for atypical pathogens of pneumonia (Legionella pneumophilia, Mycoplasma pneumoniae, Chlamydia pneumoniae, and Bordetella pertussis) between January 2016 and August 2022 were included. Positive results were adjudicated in a clinical context using pre-defined criteria. A cost analysis of diagnostic testing was performed. RESULTS: Note that, 1021 unique tests for atypical pathogens of pneumonia were performed among 481 transplant recipients. The testing positivity rate was 0.7% (n = 7). After clinical adjudication, there were three cases of proven Legionella and one case of possible Mycoplasma infection. All cases of legionellosis were in transplant recipients within 1-year post-transplantation with recently augmented immunosuppression and lymphopenia. The possible case of Mycoplasma infection was in an HSCT recipient with augmented immunosuppression. The cost of all tests ordered was $50,797.73. CONCLUSION: The positivity rate of tests for atypical pneumonia was very low in this transplant cohort. An algorithmic approach that targets testing for those with compatible host, clinical, radiographic, and epidemiologic factors, and provides guidance on test selection and test interpretation, may improve the diagnostic yield and lead to substantial cost savings.

Clinical outcomes of baloxavir versus oseltamivir in immunocompromised patients.

BACKGROUND: Neuraminidase inhibitors, including oseltamivir, are the treatment standard for influenza. Baloxavir, a novel antiviral, demonstrated comparable outcomes to oseltamivir in outpatients with influenza. Baloxavir was equally effective as oseltamivir in a retrospective study of hospitalized patients with influenza at our institution. However, the efficacy of baloxavir in immunocompromised patients is unclear. METHODS: We conducted a retrospective cohort study of immunocompromised adult patients hospitalized with influenza A who received baloxavir from January 2019 to April 2019 or oseltamivir from January 2018 to April 2018. Demographic and clinical outcomes were assessed. Primary outcomes were time from antiviral initiation to resolution of hypoxia and fever. Secondary outcomes were length of stay (LOS), intensive care unit (ICU) care, ICU LOS, and 30-day mortality. RESULTS: Of 95 total patients, 52 received baloxavir and 43 received oseltamivir. Other than younger age (57.5 vs. 65; p = .035) and longer duration between vaccination and symptom onset (114 vs. 86 days; p = .001) in the baloxavir group, baseline characteristics did not differ. H1 was the predominant subtype in the baloxavir group (65.3%) versus H3 in the oseltamivir group (85.7%). When comparing baloxavir to oseltamivir, there was no significant difference in median time from antiviral initiation to resolution of hypoxia (59.9 vs. 42.5 h) and to resolution of fever (21.6 vs. 26.6 h). There were no differences in secondary outcomes. CONCLUSION: Baloxavir was not associated with longer time to resolution of hypoxia or fever in comparison to oseltamivir. Results must be taken in context of variations in seasonal influenza subtype and resistance rates.

The respiratory syncytial virus vaccines are here: Implications for solid organ transplantation.

In 2023, the Food and Drug Administration approved 2 recombinant subunit respiratory syncytial virus (RSV) vaccines based on prefusion RSV F glycoproteins for the prevention of RSV-associated lower respiratory tract disease. These vaccines were subsequently recommended for individuals ≥60 years of age using shared clinical decision-making by the Center for Disease Control and Prevention's Advisory Committee on Immunization Practices. The development, deployment, and uptake of respiratory virus vaccines are of particular importance for solid organ recipients who are at higher risk of infectious complications and poor clinical outcomes, including from RSV-associated lower respiratory tract disease, compared to patients without immunocompromise. This review aims to summarize what is currently known about the burden of RSV disease in solid organ transplantation, to describe the currently available tools to mitigate the risk, and to highlight considerations regarding the implementation of these vaccines before and after transplantation. We also explore areas of unmet need for organ transplant recipients including questions of RSV vaccine effectiveness and safety, inequities in disease and vaccine access based on race and socioeconomic status, and expansion of coverage to immunocompromised individuals below the age of 60 years.

Current Concepts in the Diagnosis and Management of Pneumocystis Pneumonia in Solid Organ Transplantation.

Pneumocystis infection manifests predominantly as an interstitial pneumonia in immunocompromised patients. Diagnostic testing in the appropriate clinical context can be highly sensitive and specific and involves radiographic imaging, fungal biomarkers, nucleic acid amplification, histopathology, and lung fluid or tissue sampling. Trimethoprim-sulfamethoxazole remains the first-choice agent for treatment and prophylaxis. Investigation continues to promote a deeper understanding of the pathogen's ecology, epidemiology, host susceptibility, and optimal treatment and prevention strategies in solid organ transplant recipients.

Building an Infectious Disease Diversity, Equity, and Antiracism (ID2EA) Curriculum: A Single Center's Experience and Reflections.

In response to longstanding healthcare inequities unmasked by the Coronavirus Disease 2019 pandemic, the infectious diseases (ID) section at the Yale School of Medicine designed and implemented a pilot curriculum integrating Infectious Disease Diversity, Equity, and Antiracism (ID2EA) into ID educational training and measured program outcomes. We herein describe a mixed-methods assessment of section members on whether the ID2EA curriculum affected their beliefs and behaviors regarding racism and healthcare inequities. Participants rated the curriculum as useful (92% averaging across sessions) and effective in achieving stated learning objectives (89% averaging across sessions), including fostering understanding of how inequities and racism are linked to health disparities and identifying strategies to effectively deal with racism and inequities. Despite limitations in response rates and assessment of longer-term behavioral change, this work demonstrates that training in diversity, equity, and antiracism can be successfully integrated into ID physicians' educational activities and affect physicians' perspectives on these topics.

Longitudinal Immune Profiling of a Severe Acute Respiratory Syndrome Coronavirus 2 Reinfection in a Solid Organ Transplant Recipient.

BACKGROUND: The underlying immunologic deficiencies enabling severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfection are currently unknown. We describe deep longitudinal immune profiling of a transplant recipient hospitalized twice for coronavirus disease 2019 (COVID-19). METHODS: A 66-year-old male renal transplant recipient was hospitalized with COVID-19 March 2020 then readmitted to the hospital with COVID-19 233 days after initial diagnosis. Virologic and immunologic investigations were performed on samples from the primary and secondary infections. RESULTS: Whole viral genome sequencing and phylogenetic analysis revealed that viruses causing both infections were caused by distinct genetic lineages without evidence of immune escape mutations. Longitudinal comparison of cellular and humoral responses during primary SARS-CoV-2 infection revealed that this patient responded to the primary infection with low neutralization titer anti-SARS-CoV-2 antibodies that were likely present at the time of reinfection. CONCLUSIONS: The development of neutralizing antibodies and humoral memory responses in this patient failed to confer protection against reinfection, suggesting that they were below a neutralizing titer threshold or that additional factors may be required for efficient prevention of SARS-CoV-2 reinfection. Development of poorly neutralizing antibodies may have been due to profound and relatively specific reduction in naive CD4 T-cell pools. Seropositivity alone may not be a perfect correlate of protection in immunocompromised patients.

Longitudinal immune profiling of a SARS-CoV-2 reinfection in a solid organ transplant recipient.

The underlying immunologic deficiencies enabling SARS-CoV-2 reinfections are currently unknown. Here we describe a renal-transplant recipient who developed recurrent, symptomatic SARS-CoV-2 infection 7 months after primary infection. To elucidate the immunological mechanisms responsible for reinfection, we performed longitudinal profiling of cellular and humoral responses during both primary and recurrent SARS-CoV-2 infection. We found that the patient responded to the primary infection with transient, poor-quality adaptive immune responses that was further compromised by intervening treatment for acute rejection of the renal allograft prior to reinfection. Importantly, we identified the development of neutralizing antibodies and humoral memory responses prior to SARS-CoV-2 reinfection. However, these neutralizing antibodies failed to confer protection against reinfection, suggesting that additional factors are required for efficient prevention of SARS-CoV-2 reinfection. Further, we found no evidence supporting viral evasion of primary adaptive immune responses, suggesting that susceptibility to reinfection may be determined by host factors rather than pathogen adaptation.

Case Study: Longitudinal immune profiling of a SARS-CoV-2 reinfection in a solid organ transplant recipient.

Prior to the emergence of antigenically distinct SARS-CoV-2 variants, reinfections were reported infrequently - presumably due to the generation of durable and protective immune responses. However, case reports also suggested that rare, repeated infections may occur as soon as 48 days following initial disease onset. The underlying immunologic deficiencies enabling SARS-CoV-2 reinfections are currently unknown. Here we describe a renal transplant recipient who developed recurrent, symptomatic SARS-CoV-2 infection - confirmed by whole virus genome sequencing - 7 months after primary infection. To elucidate the immunological mechanisms responsible for SARS-CoV-2 reinfection, we performed longitudinal profiling of cellular and humoral responses during both primary and recurrent SARS-CoV-2 infection. We found that the patient responded to the primary infection with transient, poor-quality adaptive immune responses. The patient's immune system was further compromised by intervening treatment for acute rejection of the renal allograft prior to reinfection. Importantly, we also identified the development of neutralizing antibodies and the formation of humoral memory responses prior to SARS-CoV-2 reinfection. However, these neutralizing antibodies failed to confer protection against reinfection, suggesting that additional factors are required for efficient prevention of SARS-CoV-2 reinfection. Further, we found no evidence supporting viral evasion of primary adaptive immune responses, suggesting that susceptibility to reinfection may be determined by host factors rather than pathogen adaptation in this patient. In summary, our study suggests that a low neutralizing antibody presence alone is not sufficient to confer resistance against reinfection. Thus, patients with solid organ transplantation, or patients who are otherwise immunosuppressed, who recover from infection with SARS-CoV-2 may not develop sufficient protective immunity and are at risk of reinfection.

Diagnostic Testing of COVID-19 in Solid Organ Transplantation: Current Clinical Application and Future Strategies.

PURPOSE OF REVIEW: While a great deal of literature has been published recently on the viral kinetics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and diagnostic testing performance for coronavirus disease 2019 (COVID-19) in the general population, a relative paucity of information has come to light regarding implications of COVID-19 diagnostics for solid organ transplantation. This review examines the current state of knowledge regarding the two principal diagnostic testing strategies for SARS-CoV-2 infection, polymerase chain reaction (PCR)-based testing and serology, and discusses COVID-19 diagnostic implications for solid organ transplantation. RECENT FINDINGS: The interpretation of diagnostics for SARS-CoV-2 infection can present several challenges and raises questions regarding optimal donor and candidate screening as well as infection prevention practices in solid organ transplant recipients with SARS-CoV-2 infection. Guidance from several societies regarding donor and recipient suitability for transplantation during the COVID-19 pandemic is reviewed. Prolonged positive testing by polymerase chain reaction has been described in transplant recipients which may impact infection prevention practices. SUMMARY: The COVID-19 pandemic has put multiple aspects of solid organ transplantation at risk, with impacts on donor and recipient suitability, and mitigation of infection and transmission after transplantation. Accumulating evidence regarding diagnostic fidelity and transmissibility of SARS-CoV-2 in immunocompromised patients will continue to inform optimal practices surrounding solid organ transplantation during the COVID-19 pandemic.

Pseudo-Thrombotic Thrombocytopenic Purpura due to Severe Vitamin B12 Deficiency.

As a subset of microangiopathic hemolytic anemia, thrombotic thrombocytopenic purpura can present with a constellation of symptoms similar to the hemolytic anemia attributed to severe vitamin B12 deficiency. There have been few case reports in the medical literature concerning the development of a clinical syndrome consistent with microangiopathic hemolytic anemia attributable to B12 deficiency. We report a case of B12 deficiency leading to microangiopathic hemolytic anemia that was corrected solely with a ten-day course of intramuscular cobalamin replacement. Prompt diagnostic and clinical evaluation utilizing specific exclusion parameters can promote accurate and safe treatment of the clinical syndrome of microangiopathic hemolytic anemia related to B12 deficiency.

Novel small leucine-rich repeat protein podocan is a negative regulator of migration and proliferation of smooth muscle cells, modulates neointima formation, and is expressed in human atheroma.

BACKGROUND: Smooth muscle cell (SMC) migration and proliferation critically influence the clinical course of vascular disease. We tested the effect of the novel small leucine-rich repeat protein podocan on SMC migration and proliferation using a podocan-deficient mouse in combination with a model of arterial injury and aortic explant SMC culture. In addition, we examined the effect of overexpression of the human form of podocan on human SMCs and tested for podocan expression in human atherosclerosis. In all these conditions, we concomitantly evaluated the Wnt-TCF (T-cell factor) pathway. METHODS AND RESULTS: Podocan was strongly and selectively expressed in arteries of wild-type mice after injury. Podocan-deficient mice showed increased arterial lesion formation compared with wild-type littermates in response to injury (P<0.05). Also, SMC proliferation was increased in arteries of podocan-deficient mice compared with wild-type (P<0.05). In vitro, migration and proliferation were increased in podocan-deficient SMCs and were normalized by transfection with the wild-type podocan gene (P<0.05). In addition, upregulation of the Wnt-TCF pathway was found in SMCs of podocan-deficient mice both in vitro and in vivo. On the other hand, podocan overexpression in human SMCs significantly reduced SMC migration and proliferation, inhibiting the Wnt-TCF pathway. Podocan and a Wnt-TCF pathway marker were differently expressed in human coronary restenotic versus primary lesions. CONCLUSIONS: Podocan appears to be a potent negative regulator of the migration and proliferation of both murine and human SMCs. The lack of podocan results in excessive arterial repair and prolonged SMC proliferation, which likely is mediated by the Wnt-TCF pathway.