Introduction. The diagnosis of pulmonary infection and the identification of pathogens are still clinical challenges in immunocompromised patients. Metagenomic next-generation sequencing (mNGS) has emerged as a promising infection diagnostic technique. However, its diagnostic value in immunocompromised patients needs further exploration. Purposes. This study was to evaluate the diagnostic value of mNGS compared with comprehensive conventional pathogen tests (CTs) in the etiology of pneumonia in immunocompromised patients and immunocompetent patients. Methods. We retrospectively reviewed 53 patients who were diagnosed with pneumonia from May 2019 to June 2021. There were 32 immunocompromised patients and 21 immunocompetent patients with pneumonia who received both mNGS and CTs. The diagnostic performance was compared between mNGS and CTs in immunocompromised patients, using the composite diagnosis as the reference standard. And, the diagnostic value of mNGS for mixed infections was further analyzed. Results. Compared to immunocompetent patients, the most commonly pathogens, followed by Cytomegalovirus, Pneumocystis jirovecii and Klebsiella pneumoniae in immunocompromised patients. Furthermore, more mixed infections were diagnosed, and bacterial-fungal-virus coinfection was the most frequent combination (43.8%). mNGS can detect more types of pathogenic microorganisms than CTs in both groups (78.1% vs. 62.5%, and 57.1% vs. 42.9%, ). The overall diagnostic positive rate of mNGS for pathogens was higher in immunocompromised patients ( ). In immunocompromised patients, a comparable diagnostic accuracy of mNGS and CTs was found for bacterial, fungal, and viral infections and coinfection. mNGS had a much higher sensitivity for bacterial infections (92.9% vs. 50%, ) and coinfections (68.8% vs. 48.3%, ), and it had no significant advantage in the detection of fungal infections, mainly due to the high sensitivity for Pneumocystis jirovecii in both groups. Conclusion. mNGS is more valuable in immunocompromised patients and exhibits apparent advantages in detecting bacterial and mixed infections. It may be an alternative or complementary diagnostic method for the diagnosis of complicated infections in immunocompromised patients.

Metagenomic next-generation sequencing (mNGS) has become an available method for pathogen detection. The clinical application of mNGS requires further evaluation. We conducted a cross-sectional study of 104 patients with suspected infection between May 2019 and May 2021. The risk factors associated with infection were analyzed using univariate logistic analysis. The diagnostic performance of pathogens was compared between mNGS and conventional microbiological tests. About 104 patients were assigned into 3 groups: infected group (n = 69), noninfected group (n = 20), and unknown group (n = 15). With the composite reference standard (combined results of all microbiological tests, radiological testing results, and a summary of the hospital stay of the patient) as the gold standard, the sensitivity, specificity, positive predictive value, negative predictive value of mNGS was 84.9%, 50.0%, 88.6%, and 42.1%, respectively. Compared with conventional microbiological tests, mNGS could detect more pathogens and had obvious advantages in Mycobacterium tuberculosis, Aspergillus, and virus detection. Moreover, mNGS had distinct benefits in detecting mixed infections. Bacteria–fungi–virus mixed infections were the most common in patients with severe pneumonia. mNGS had a higher sensitivity than conventional microbiological tests, especially for M. tuberculosis, Aspergillus, viruses, and mixed infections. We suggest that mNGS should be used more frequently in the early diagnosis of pathogens in critically ill patients in the future.

Primary EBV-positive mucocutaneous ulcer (EBVMCU) is a rare and indolent disorder occurring in the oropharynx, skin, and gastrointestinal tract, with remission after removal of the immunosuppressive causes. We present a 69-year-old woman with heartburn, regurgitation of gastric acid, enlarged lymph nodes, and parotid glands. The endoscopic examination showed a circumscribed ulcer in the lower esophagus. A biopsy pathology indicated an esophageal EBV-associated lymphoproliferative disorder and a parotid gland/lymph node indolent B-cell lymphoma. Interestingly, the patient did not undergo any treatment, but the endoscopic ulcer improved significantly after more than 2 months. The last pathology showed EBV negativity, and EBVMCU was considered in combination with clinical and endoscopic manifestations. We followed up with the patient at 6 months, and the symptoms of acid reflux and heartburn had disappeared. Our case demonstrates that EBVMCU may occur in the esophagus with spontaneous regression.