Beta-D-Glucan in Patients with Haematological Malignancies

Dynamic changes in serum (1-3)-β-D-glucan caused by intravenous immunoglobulin infusion: A prospective study

PURPOSE

The purpose of this study was to investigate the dynamic changes in serum (1-3)-β-D-glucan (BDG) caused by intravenous immunoglobulins (IVIG) infusion in adults.

METHODS

This study included patients who received IVIG infusion from October 2021 to October 2022 during hospitalization. We randomly examined two IVIG samples for every patient. Serum samples were collected at nine time points: before (Tpre), immediately (T1-0), 6h (T1-1) and 12h (T1-2) later on the first day; immediately (T2-0) and six hours later (T2-1) on the second day during IVIG infusion, and within three days after IVIG infusion (Ta1, Ta2, and Ta3, respectively). The Friedman test was used for statistical analysis.

RESULTS

A total of 159 serum BDG from 19 patients were included in the analysis. The BDG content of IVIG ranged from 249 pg/ml to 4812 pg/ml. Patients had significantly elevated serum BDG on T1-0 (176 (113, 291) pg/ml, p = 0.002) and Ta1 (310 (199, 470) pg/ml, p < 0.001), compared with Tpre (41 (38, 65) pg/ml). The increments of serum BDG (ΔBDG) were associated with BDG concentration of IVIG (Spearman r = 0.59, p = 0.02). Individuals with abnormal renal function indexes showed higher serum ΔBDG values at Ta1 (403 (207, 484) pg/ml) than patients with normal renal function (172 (85, 316) pg/ml, p = 0.036).

CONCLUSION

Patients who received IVIG had significantly higher serum BDG values. Elevated BDG levels correlate with BDG content of IVIG and abnormal renal function indexes.

A Diagnostic Stewardship Intervention to Improve Utilization of 1,3 β-D-Glucan Testing at a Single Academic Center: Five-Year Experience

Background

(1,3)- β-D-glucan (BDG) testing is one of the noninvasive tests to aid diagnosis of invasive fungal infections (IFIs). The study results have been heterogenous, and diagnostic performance varies depending on the risks for IFI. Thus, it is important to select appropriate patients for BDG testing to prevent false-positive results. An algorithmic diagnostic stewardship intervention was instituted at a single academic medical center to improve BDG test utilization.

Methods

The BDG test order in the electronic health record was replaced with the BDG test request order, which required approval to process the actual test order. The approval criteria were (1) immunocompromised or intensive care unit patient and (2) on empiric antifungal therapy, or inability to undergo invasive diagnostic procedures. A retrospective observational study was conducted to evaluate the efficacy of the intervention by comparing the number of BDG tests performed between 1 year pre- and post-intervention. Safety was assessed by chart review of the patients for whom BDG test requests were deemed inappropriate and rejected.

Results

The number of BDG tests performed per year decreased by 85% from 156 in the pre-intervention period to 24 in the post-intervention period. The average monthly number of BDG tests performed was significantly lower between those periods (P = .002). There was no delay in IFI diagnosis or IFI-related deaths in the patients whose BDG test requests were rejected. The sustained effectiveness of the intervention was observed for 5 years.

Conclusions

Institution of the diagnostic stewardship intervention successfully and safely improved BDG test utilization.

Evaluation of the Performance of the Dynamiker Fungus (1-3)-β-D-Glucan and Fungitell Assay for Diagnosis of Candidemia: Need for New Cut-off Development and Test Validation

(1-3)-Beta-D Glucan (BDG) detection has shown to be a highly effective tool to diagnose invasive fungal infections. Therefore, this study aimed to compare clinical characteristics of the Fungitell (FA) and Dynamiker Fungus (1-3)-β-D-Glucan assay (DFA) for the diagnosis of candidemia. Using DFA and FA, the BDG levels of 57 serum samples from case and control groups were determined. The kappa coefficient (κ) and Spearman's rank correlation (rs) were used to examine the consistency of assays on a quantitative and qualitative level, respectively. The sensitivity, specificity, and accuracy were 94.6 %, 65.0 %, and 87.7% for DFA, and 94.6 %, 75.0 %, and 89.4 % for FA, respectively. The performance of the DFA for the diagnosis of candidemia was highly consistent with that of the FA, both quantitatively (rs: 0.9) and qualitatively (kappa = 0.78). Collectively, the DFA assay performed excellently in comparison to the FA for the diagnosis of candidemia.

Invasive fusariosis

Invasive fusariosis is a serious invasive fungal disease, affecting immunocompetent and, more frequently, immunocompromised patients. Localized disease is the typical clinical form in immunocompetent patients. Immunocompromised hosts at elevated risk of developing invasive fusariosis are patients with acute leukemia receiving chemotherapeutic regimens for remission induction, and those undergoing allogeneic hematopoietic cell transplant. In this setting, the infection is usually disseminated with positive blood cultures, multiple painful metastatic skin lesions, and lung involvement. Currently available antifungal agents have poor in vitro activity against Fusarium species, but a clear-cut correlation between in vitro activity and clinical effectiveness does not exist. The outcome of invasive fusariosis is largely dependent on the resolution of immunosuppression, especially neutrophil recovery in neutropenic patients.

Microbiological Non-Culture-Based Methods for Diagnosing Invasive Pulmonary Aspergillosis in ICU Patients

The diagnosis of invasive pulmonary aspergillosis (IPA) in intensive care unit (ICU) patients is crucial since most clinical signs are not specific to invasive fungal infections. To detect an IPA, different criteria should be considered. Next to host factors and radiological signs, microbiological criteria should be fulfilled. For microbiological diagnostics, different methods are available. Next to the conventional culture-based approaches like staining and culture, non-culture-based methods can increase sensitivity and improve time-to-result. Besides fungal biomarkers, like galactomannan and (1→3)-β-D-glucan as nonspecific tools, molecular-based methods can also offer detection of resistance determinants. The detection of novel biomarkers or targets is promising. In this review, we evaluate and discuss the value of non-culture-based microbiological methods (galactomannan, (1→3)-β-D-glucan, Aspergillus PCR, new biomarker/targets) for diagnosing IPA in ICU patients.

Sensitivity of Serum Beta-D-Glucan in Candidemia According to Candida Species Epidemiology in Critically Ill Patients Admitted to the Intensive Care Unit

Serum beta-D-glucan (BDG) determination plays an important role in the diagnosis of candidemia among critically ill patients admitted to the intensive care unit (ICU). However, BDG levels measured may be lower in the case of infections caused by some non-albicans species, such as C. parapsilosis and C. auris. The aim of this single-center study was to investigate the sensitivity of serum BDG for the diagnosis of candidemia stratified according to causative Candida species in ICU patients. This was a single-center, retrospective study, including all adult patients admitted to ICU during the period 2018–2021. All episodes of candidemia with a determination of BDG available within 3 days before or after positive blood culture were recorded. The preplanned primary objective was to investigate the sensitivity of serum BDG to detect candidemia early and the effect of different Candida species. The secondary objective was to measure serum BDG in patients with candidemia from different Candida species. In total, 146 candidemia episodes in 118 patients were analyzed. Median BDG value for C. albicans candidemia (182 pg/mL) was higher than that observed for C. parapsilosis (78 pg/mL, p = 0.015) and C. auris (48 pg/mL, p = 0.022). The overall sensitivity of BDG for the diagnosis of candidemia was low (47%, 95% CI 39–55%). In conclusion, in critically ill patients admitted to ICU, serum BDG levels for candidemia were different among species, with lower levels confirmed for C. parapsilosis and C. auris. Serum BDG sensitivity for early detection of candidemia was lower than previously reported in other ICU populations.