Risk factors associated with Pneumocystis jirovecii pneumonia in non-HIV immunocompromised patients and co-pathogens analysis by metagenomic next-generation sequencing

High prevalence of pneumocystis pneumonia in interstitial lung disease: a retrospective study

BACKGROUND

Interstitial lung disease (ILD) is a new risk category for pneumocystis pneumonia (PCP) with a high mortality rate. The definite diagnostic criteria of PCP in ILD patients have not been established until now. The aims of this study were to identify potential risk factors of PCP in patients with ILD, and to evaluate the performance of metagenomic next-generation sequencing (mNGS), CD4 + T cell count, (1-3)-β-D-Glucan (BG) and lactate dehydrogenase (LDH) in the diagnosis of PCP in ILD patients.

METHODS

This is a retrospective, single-center, case-control study. ILD patients who underwent mNGS from December 2018 to December 2022 were included in the study. Based on the diagnosis criteria of PCP, these patients were divided into PCP-ILD and non-PCP-ILD groups. The potential risk factors for PCP occurrence in ILD patients were analysed via logistic regression. The diagnostic efficacy of mNGS was compared with serological biomarkers.

RESULTS

92 patients with ILD were enrolled, 31 of which had a definite PCP and were assigned to the PCP-ILD group while 61 were to the non-PCP-ILD group. The infection rate of PJ in ILD patients was 33.7% (31/92). The history of glucocorticoid therapy, CD4 + T cell count, BG level and traction bronchiectasis on HRCT were associated with PCP occurrence in ILD patients. LDH level did not reach statistical significance in the logistic regression analysis. mNGS was confirmed as the most accurate test for PCP diagnosis in ILD patients.

CONCLUSION

ILD is a new risk group of PCP with high PCP prevalence. Clinicians should pay close attention to the occurrence of PCP in ILD patients who possess the risk factors of previous glucocorticoid therapy, decreased CD4 + T cell count, increased BG level and absence of traction bronchiectasis on HRCT. mNGS showed the most excellent performance for PCP diagnosis in ILD patients. Peripheral blood CD4 + T cell count and BG level are alternative diagnostic methods for PCP in ILD patients. However, the diagnostic value of serum LDH level was limited in ILD patients.

Protocol for the systematic review of the Pneumocystis jirovecii-associated pneumonia in non-HIV immunocompromised patients

INTRODUCTION

Pneumocystis jirovecii pneumonia (PJP) is a well-known and frequent opportunistic infection in HIV patients. However, there has been an increase in the number of reports of PJP in other immunosuppressed patients with autoimmune inflammatory disorders or because of chemotherapy and high doses of steroids, especially when used in combination as part of immunosuppressive therapy.

OBJECTIVE

Despite the increasing importance of PJP in non-HIV patients, there is a lack of comprehensive and updated information on the epidemiology, pathogenesis, diagnosis, microbiology, treatments, and prophylaxis of this infection in this population. Therefore, the objective of this systematic review is to synthesize information on these aspects, from a perspective of evidence-based medicine.

METHODS

The protocol is prepared following the preferred reporting items for systematic reviews and meta-analyses (PRISMA-P) guidelines. We will perform a systematic review of literature published between January 2010 and July 2023, using the databases PubMed, Google Scholar, ScienceDirect, and Web of Science. In addition, manual searches will be carried out through related articles, and references to included articles. The main findings and clinical outcomes were extracted from all the eligible studies with a standardized instrument. Two authors will independently screen titles and abstracts, review full texts, and collect data. Disagreements will be resolved by discussion, and a third reviewer will decide if there is no consensus. We will synthesize the results using a narrative or a meta-analytic approach, depending on the heterogeneity of the studies.

EXPECTED RESULTS

It is expected that this systematic review will provide a comprehensive and up-to-date overview of the state-of-the-art of PJP in non-HIV patients. Furthermore, the study will highlight possible gaps in knowledge that should be addressed through new research.

CONCLUSIONS

Here, we present the protocol for a systematic review which will consider all existing evidence from peer-reviewed publication sources relevant to the primary and secondary outcomes related to diagnosing and managing PJP in non-HIV patients.

[Metagenomic next-generation sequencing for the diagnosis of Pneumocystis jirovecii pneumonia after allogeneic hematopoietic stem cell transplantation]

Objectives: To investigate the value of metagenomic next-generation sequencing (mNGS) in the diagnosis of Pneumocystis jirovecii pneumonia (PJP) in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: The data of 98 patients with suspected pulmonary infection after allo-HSCT who underwent pathogen detection from bronchoalveolar lavage fluid between June 2016 and August 2023 at Nanfang Hospital were analyzed. The diagnostic performance of mNGS, conventional methods, and real-time quantitative polymerase chain reaction (qPCR) for PJP were compared. Results: A total of 12 patients were diagnosed with PJP, including 11 with a proven diagnosis and 1 with a probable diagnosis. Among the patients with a proven diagnosis, 1 was positive by both conventional methods and qPCR, and 10 were positive by qPCR only. Pneumocystis jirovecii was detected by mNGS in all 12 patients. The diagnostic sensitivity of mNGS for PJP was 100%, which was greater than that of conventional methods (8.3%, P=0.001) and similar to that of qPCR (91.6%, P=1.000) . A total of 75% of the patients developed mixed pulmonary infections, and cytomegalovirus and Epstein-Barr virus were the most common pathogens. Mixed infection was detected in eight patients by mNGS and in five patients by qPCR, but not by conventional methods (P=0.008) . Conclusions: mNGS had good sensitivity for diagnosing PJP after allo-HSCT and was advantageous for detecting mixed infectious pathogens; therefore, mNGS might be an effective supplement to regular detection methods and qPCR.

Purine antimetabolites associated Pneumocystis jirovecii pneumonia

PURPOSE

To detect the possible safety signal of purine antimetabolites associated with Pneumocystis jirovecii pneumonia through disproportionality analysis in the FDA Adverse Event Reporting System (FAERS) Database.

METHODS

A case/non-case retrospective disproportionality analysis was performed in the publicly available FAERS database using AERSmine (2004Q1-2021Q3). Four models were developed to explore the signal strength of PAs among different populations with possible confounding factors. Reporting odds ratio (ROR) and Proportional reporting ratio (PRR) was used as the data mining algorithm for the analysis. A value of ROR-1.96SE > 1 and PRR ≥ 2 with an associated X2 value of 4 or more was considered the threshold for a signal.

RESULTS

A total of 7073 reports associated with Pneumocystis jirovecii pneumonia were present in the database, of which 899 reports were associated with purine antimetabolites. A crude signal strength of ROR 15.76(14.70-16.91) was obtained for purine antimetabolites associated PJP, with the highest signal strength reported with fludarabine and thioguanine [ROR 19.63(17.42-22.13); 19.45(13.21-28.63)]. Stratifying the cases based on autoimmune disorders and the cancer population revealed an ROR of 3.33(2.46-4.50) and 2.93(2.26-3.79) respectively. The highest risk of PJP with use of PAs was observed amongst children with a higher risk of nearly 2 times than the adult population [ROR 11.57(9.16-14.62)].

CONCLUSIONS

Our study provided evidence on the occurrence of PJP with the use of purine antimetabolites among the autoimmune and cancer population. We identified signals for PJP with azathioprine, mercaptopurine, thioguanine, cladribine, fludarabine, and clofarabine. More research with a superior epidemiological study design of a defined population is required to validate these findings.