Host Biomarkers of Invasive Pulmonary Aspergillosis To Monitor Therapeutic Response

Abstract

cInvasive pulmonary aspergillosis (IPA) is a life-threatening disease of immunocompromised patients that requires aggressive therapy. Detection of the disease and monitoring of the therapeutic response during IPA are complex, and current molecular diagnostics are not suitably robust. Here, we explored proteomic profiles of bronchoalveolar lavage fluid (BALF) specimens from a persistently neutropenic rabbit model of IPA. Three experimental arms, uninfected control animals, infected untreated animals, and animals infected and treated with ravuconazole/amphotericin B, were studied. Total proteins were evaluated by twodimensional (2D) gel electrophoresis, followed by matrix-assisted laser desorption ionization-time of flight/time of flight (MALDI-TOF/TOF) mass spectrometry (MS) and quantified by enzyme-linked immunosorbent assay (ELISA). Host-derived proteins haptoglobin (Hp), C-reactive protein (CRP), and annexin A1 (Anx A1) were prominently found in BALF during the IPA infection and showed significant changes in response to antifungal therapy (P < 0.0001). In serum, differences in Hp (P ‫؍‬ 0.0001) between infected and treated rabbits were observed. Preliminary in vitro studies revealed that Aspergillus fumigatussecreted proteases may contribute to the cleavage of Anx A1 during IPA. In summary, host protein biomarkers Hp, CRP, and Anx A1 may have value in monitoring therapeutic response to antifungal agents in IPA patients with confirmed disease.

Proteome analysis of bronchoalveolar lavage fluids reveals host and fungal proteins highly expressed during invasive pulmonary aspergillosis in mice and humans

“…Increased levels of haptoglobin, an acute phase protein during angioinvasion, were reported in mammals with IPA and since the protein was detected in BAL fluid as well as in serum of leukopenic rabbits, it was proposed as a candidate-circulating biomarker for IPA [16,40,41]. However, although haptoglobin was significantly elevated in leukopenic IPA mice this was not discovered in human BAL samples.…”

“…The significant enrichment of proteins involved in blood coagulation, acute phase response, and cellular response to lipoteichoic acid was not surprising as angioinvasion during IPA leads to pulmonary hemorrhage and has been demonstrated previously in blood and lung samples in rats infected with Aspergillus [ 39 ]. Increased levels of haptoglobin, an acute phase protein during angioinvasion, were reported in mammals with IPA and since the protein was detected in BAL fluid as well as in serum of leukopenic rabbits, it was proposed as a candidate-circulating biomarker for IPA [ 16 , 40 , 41 ]. However, although haptoglobin was significantly elevated in leukopenic IPA mice this was not discovered in human BAL samples.…”

“…In search for IPA biomarker candidates, body fluids such as blood, urine, and bronchoalveolar lavage (BAL) fluid have been commonly used. In most studies, a combination of protein separation by 2-dimensional isoelectric focusing with mass spectrometric identification of specific protein spots was used to identify secreted fungal antigens that are unique to pulmonary infections with A. fumigatus [ 14 – 16 ]. However, this approach suffers from a major limitation: the abundance of host proteins hampers the detection of pathogen-derived proteins that are usually present at lower concentrations.…”

Invasive mould infections in solid organ transplant patients: modifiers and indicators of disease and treatment response

“…Cytokines (serum interleukin (IL)-6, IL-8, IL-10, interferon-γ) [87], CRP [88], as well as haptoglobin (Hp) and annexin A1 (ANXA1) [89], have been proposed as potential immunological biomarker for assessing treatment response in patients with haematological malignancies [58]. All studies carried out so far [87,90,91], however, included only haemato-oncological patients.…”

Diagnostic work up to assess early response indicators in invasive pulmonary aspergillosis in adult patients with haematologic malignancies

“…Two additional host biomarkers, haptoglobin (Hp) and annexin A1 (ANXA1) display a dynamic response during antifungal therapy . In a study carried out on a small number (15) of patients, Hp levels increased constantly in non‐responders while ANXA1 levels decreased .…”