When polymerase chain reaction does not help: cytomegalovirus pneumonitis associated with very low or undetectable viral load in both blood and bronchoalveolar lavage samples after lung transplantation

Infections in Heart and Lung Transplant Recipients

Infections in heart and lung transplant recipients are complex and heterogeneous. This article reviews the epidemiology, risk factors, specific clinical syndromes, and most frequent opportunistic infections in heart and/or lung transplant recipients that will be encountered in the intensive care unit and will provide a practical approach of empirical management.

Pulmonary cytomegalovirus infection: A case report and systematic review

BACKGROUND

Cytomegalovirus (CMV) is a common virus that can cause the first infection in childhood or adolescence and reactivate later in life due to immunosuppression. CMV pneumonia is a rare illness in immunocompetent patients but is one of the most significant opportunistic infections in immunocompromised patients.

AIM

To report a case and review published cases of pulmonary CMV infection in both immunocompromised and immunocompetent patients.

METHODS

We conducted a systematic search on the MEDLINE (PubMed) database, without date or language restrictions, to identify relevant studies using Medical Subject Headings and Health Science Descriptors. We manually searched the reference lists of the included studies. Simple descriptive analysis was used to summarize the results.

RESULTS

Our search identified 445 references, and after screening, 43 studies reporting 45 cases were included in the final analysis, with 29 (64%) patients being immunocompromised and 16 (36%) being immunocompetent. Fever (82%) and dyspnea (75%) were the most common clinical findings. Thoracic computed tomography showed bilateral ground-glass opacities, a relevant differential diagnosis for severe acute respiratory syndrome coronavirus 2 infection. The majority of patients (85%) received antiviral therapy, and 89% of patients recovered, while 9% of patients died.

CONCLUSION

CMV pneumonia should be considered as a differential diagnosis for coronavirus disease 2019 pneumonia, especially in immunocompromised patients. Clinicians should be aware of the clinical presentation, management, and outcomes of CMV pneumonia to guide appropriate treatment decisions.

Human cytomegalovirus: a survey of end-organ diseases and diagnostic challenges in solid organ transplant recipients

PURPOSE OF REVIEW

Human cytomegalovirus (CMV) infection is one of the most important infectious complications in solid organ transplant (SOT) recipients, leading to significant morbidity and mortality. Therefore, early detection and prompt treatment are imperative to improve transplant outcomes. This article highlights the clinical characteristics of the most common CMV end-organ diseases in SOT recipients and their diagnostic modalities and challenges.

RECENT FINDINGS

CMV can cause a variety of end-organ diseases in SOT recipients. Although CMV nucleic acid amplification by polymerase chain reaction (PCR) is frequently employed to detect CMV reactivation or infection, its predictive value for various CMV end-organ diseases remains uncertain. Given the limitation of PCR or other noninvasive tests, confirmation of CMV end-organ disease may require tissue biopsy, which may not be feasible or available, or may cause untoward complications.

SUMMARY

The utility of PCR to diagnose CMV end-organ disease is limited. As CMV can infect any organ system(s), clinicians caring for SOT recipients need to maintain vigilance for any signs and symptoms of end-organ disease to allow early recognition and prompt treatment. Invasive procedures might be needed to confirm the diagnosis and minimize the empirical use of antiviral therapy that may have substantial drug toxicities.

Prediction of immune checkpoint blockade-related hepatitis in metastatic melanoma patients

The introduction of clinical antibodies against programmed death-1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) has revolutionized cancer treatment. Immune checkpoint blockade has enormous therapeutic potential and is widely prescribed for treating various cancers. However, immune-related adverse events in checkpoint blockade-treated patients are common and limit its clinical application. Despite efforts to understand the etiology of immune-related adverse events, the underlying cellular reactions remain elusive. Recently, our group identified a subset of patients with metastatic melanoma that are predisposed to hepatitis after combined PD-1 and CTLA-4 blockade. These patients are characterized by pre-treatment expansion of effector memory CD4⁺ T cells (T_EM cells) in blood. We attributed this expansion to chronic or recurrent subclinical immune responses against cytomegalovirus (CMV) infection. Accordingly, baseline expansion of T_EM cells is a reliable biomarker of hepatitis risk that identifies a subgroup of patients who might benefit from prophylactic CMV treatment with valganciclovir.

Virus-specific memory T cell responses unmasked by immune checkpoint blockade cause hepatitis

Treatment of advanced melanoma with combined PD-1/CTLA-4 blockade commonly causes serious immune-mediated complications. Here, we identify a subset of patients predisposed to immune checkpoint blockade-related hepatitis who are distinguished by chronic expansion of effector memory CD4⁺ T cells (T_EM cells). Pre-therapy CD4⁺ T_EM cell expansion occurs primarily during autumn or winter in patients with metastatic disease and high cytomegalovirus (CMV)-specific serum antibody titres. These clinical features implicate metastasis-dependent, compartmentalised CMV reactivation as the cause of CD4⁺ T_EM expansion. Pre-therapy CD4⁺ T_EM expansion predicts hepatitis in CMV-seropositive patients, opening possibilities for avoidance or prevention. 3 of 4 patients with pre-treatment CD4⁺ T_EM expansion who received αPD-1 monotherapy instead of αPD-1/αCTLA-4 therapy remained hepatitis-free. 4 of 4 patients with baseline CD4⁺ T_EM expansion given prophylactic valganciclovir and αPD-1/αCTLA-4 therapy remained hepatitis-free. Our findings exemplify how pathogen exposure can shape clinical reactions after cancer therapy and how this insight leads to therapeutic innovations.

Infections in Heart and Lung Transplant Recipients

Infections in heart and lung transplant recipients are complex and heterogeneous. This article reviews the epidemiology, risk factors, specific clinical syndromes, and most frequent opportunistic infections in heart and/or lung transplant recipients that will be encountered in the intensive care unit and will provide a practical approach of empirical management.

Cytomegalovirus (CMV) DNA Quantitation in Bronchoalveolar Lavage Fluid From Hematopoietic Stem Cell Transplant Recipients With CMV Pneumonia

Background

Quantitative cytomegalovirus (CMV) DNA-specific polymerase chain reaction (PCR) analysis is widely used as a surveillance method for hematopoietic stem cell transplant (HCT) recipients. However, no CMV DNA threshold exists in bronchoalveolar lavage (BAL) to differentiate pneumonia from pulmonary shedding.

Methods

We tested archived BAL fluid samples from 132 HCT recipients with CMV pneumonia and 139 controls (100 patients with non-CMV pneumonia, 18 with idiopathic pneumonia syndrome [IPS], and 21 who were asymptomatic) by quantitative CMV and β-globin DNA-specific PCR.

Results

Patients with CMV pneumonia had higher median viral loads (3.9 log10 IU/mL; interquartile range [IQR], 2.6-6.0 log10 IU/mL) than controls (0 log10 IU/mL [IQR, 0-1.6 log10 IU/mL] for patients with non-CMV pneumonia, 0 log10 IU/mL [IQR, 0-1.6 log10 IU/mL] for patients with IPS, and 1.63 log10 IU/mL [IQR, 0-2.5 log10 IU/mL] for patients who were asymptomatic; P < .001 for all comparisons to patients with CMV pneumonia). Receiver operating characteristic curve analyses and predictive models identified a cutoff CMV DNA level of 500 IU/mL to differentiate between CMV pneumonia and pulmonary shedding, using current CMV pneumonia prevalence figures. However, different levels may be appropriate in settings of very high or low CMV pneumonia prevalence. The presence of pulmonary copathogens, radiographic presentation, or pulmonary hemorrhage did not alter predictive values.

Conclusion

CMV DNA load in BAL can be used to differentiate CMV pneumonia from pulmonary shedding.

Lower respiratory tract viral infections: Diagnostic role of exfoliative cytology

Viral lower respiratory tract infections (VLRTI) remain one of the most common causes of morbidity and mortality worldwide. For many years, the diagnosis of VLRTI was based on laboratory techniques such as viral isolation in cell culture, antigen detection by direct fluorescent antibody staining, and rapid enzyme immunoassay. Radiological imaging and morphology also play an important role in diagnosing these infections. Exfoliative cytology provides a simple, rapid, inexpensive, and valuable means to diagnose and manage VLRTI. Here we review viral‐associated cytomorphological changes seen in exfoliated cells of the lower respiratory tract. Diagn. Cytopathol. 2017;45:614–620. © 2017 Wiley Periodicals, Inc.

When polymerase chain reaction does not help: cytomegalovirus pneumonitis associated with very low or undetectable viral load in both blood and bronchoalveolar lavage samples after lung transplantation

Cytomegalovirus (CMV) pneumonitis occurs frequently among solid organ transplant recipients and is classically associated with significant viral replication in both blood and bronchoalveolar lavage (BAL) samples. We present a case of a 64‐year‐old lung transplant recipient who presented with CMV pneumonitis that was diagnosed based on the association of viral inclusion in the BAL sample, rapid response to ganciclovir, and absence of other infectious etiology. Surprisingly, we observed very low or undetectable viral load both in blood and BAL samples. Diagnosis of CMV pneumonitis should rely on the association of clinical, pathological, radiological, and microbiological signs, while quantitative nucleic acid amplification testing should be interpreted with caution.