Diagnosis and Treatment of Fungal Infections in Lung Transplant Recipients

Fungal colonization before or after lung transplantation has no negative impact on survival or the development of chronic lung allograft dysfunction

Introduction

Long-term survival following lung transplantation (LTx) faces impediments due to chronic lung allograft dysfunction (CLAD), while infections hinder short-term survival. Fungal colonization and invasive fungal infections (IFI) are common within the first year after LTx. There is ongoing debate regarding the impact of such events on CLAD development and mortality. This study aims to investigate this matter further.

Methods

A total of 134 LTx recipients transplanted between 2011 and 2020 were included. The median follow-up time was 3.9 years. Fungal colonization and IFI were defined according to international consensus guidelines and were noted if present within the first 12 months after LTx.

Results

Postoperative fungal colonization was found in 101 patients, and 14 patients had an IFI within twelve months of transplantation. Nineteen patients were neither colonized nor infected. Out of the 115 patients with colonization or IFI, 61 patients had growth of a yeast such as Candida species (spp.). Fifty-six patients were colonized prior to LTx. Being colonized with fungus before or within the first 12 months post-LTx did not significantly affect survival or CLAD development.

Conclusions

The results of the current study indicate that fungal colonization either pre-transplantation or within the first 12 months after does not correlate with increased risks of mortality or CLAD development. These findings show that while fungal colonization is a common occurrence in LTx recipients, it does not predispose the patients of the cohort to adverse outcomes.

The epidemiology of invasive fungal infections in transplant recipients

Transplant patients, including solid-organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients, are exposed to various types of complications, particularly rejection. To prevent these outcomes, transplant recipients commonly receive long-term immunosuppressive regimens that in turn make them more susceptible to a wide array of infectious diseases, notably those caused by opportunistic pathogens. Among these, invasive fungal infections (IFIs) remain a major cause of mortality and morbidity in both SOT and HSCT recipients. Despite the continuing improvement in early diagnostics and treatments of IFIs, the management of these infections in transplant patients is still complicated. Here, we provide an overview concerning the most recent trends in the epidemiology of IFIs in SOT and HSCT recipients by describing the prominent yeast and mold species involved, the timing of post-transplant IFIs and the risk factors associated with their occurrence in these particularly weak populations. We also give special emphasis into basic research advances in the field that recently suggested a role of the global and long-term prophylactic regimen in orchestrating various biological disturbances in the organism and conditioning the emergence of the most adapted fungal strains to the particular physiological profiles of transplant patients.

Culture-independent diagnostic approaches for invasive aspergillosis in solid organ transplant recipients

Prompt and accurate diagnosis of invasive aspergillosis (IA) is crucial for immunocompromised patients, including those who have received a solid organ transplant (SOT). Despite their low sensitivity, microscopic detection and conventional culture are considered the 'gold standard' methods. In conjunction with conventional culture, culture-independent assays such as serum galactomannan testing and Aspergillus polymerase chain reaction (PCR) have been incorporated into the diagnostic process for IA. The recently revised consensus definitions from the European Organization for Research and Treatment of Cancer and the Mycosis Study Group have adjusted the threshold for positive galactomannan testing based on the sample type, and have excluded 1,3-β-D-glucan testing as a mycological criterion. Following extensive standardization efforts, positive Aspergillus PCR tests using serum, plasma, or bronchoalveolar lavage fluid have been added. However, there are limited studies evaluating the clinical utility of these culture-independent assays for the early diagnosis of IA in SOT recipients. Therefore, further research is required to determine whether these assays could aid in the early diagnosis of IA in SOT recipients, particularly in relation to the organ transplanted. In this review, we examine the culture-independent diagnostic methods for IA in SOT recipients, as well as the clinical utility of these assays.