galactomannan and Immunologic-Deficiency-Syndromes

Invasive aspergillosis (IA) remains a critical issue in immunosuppressed patients. Detection of galactomannan antigen (GM) in serum samples is included as a criterion of IA by the European Organization for the Research and Treatment of Cancer/Mycoses Study Group. Nevertheless, Aspergillus DNA detection by polymerase chain reaction (PCR) has not yet been included because clinical data validation is lacking. The present study describes the simultaneous performance of GM and PCR tests as routine methods for IA diagnosis.. During the period January 2012 to December 2017, a total of 156 white children hospitalized in a tertiary children's hospital of Athens (97 boys and 59 girls; age range, 5 months-14 years) were examined as possible cases of IA. Patients were classified into 4 groups based on their underlying diseases: hematologic malignancies (107 of 156 [68.6%]), solid tumors (16 of 156 [10.2%]), primary immunodeficiency (12 of 156 [7.7%]), and hereditary immunodeficiency (21 of 156 [13.5%]). GM detection was made with the Platelia Aspergillus Ag kit (Bio-Rad Laboratories, Hercules, California). Sera with a cut-off index ≥0.5 on at least 2 separate blood collections were considered positive. Serum detection of Aspergillus DNA was conducted with real-time PCR MycAssay Aspergillus assay (Myconostica Ltd, Cambridge, United Kingdom). PCR positivity was determined by using a threshold of 38 cycles in at least 1 serum sample. Four or more successive samples per patient were tested.. Overall, 28 of 156 patients (53 of 744 serum samples) were found positive. Eleven patients were positive using both methods (24 samples). Four children were positive only by PCR (6 samples), whereas 13 (23 samples) were positive only with GM in consecutive samples. Agreement of both methods, GM(+)/PCR(+) or GM(-)/PCR(-), was found in 139 patients (90% of total patients) and 715 samples (96.1% of total samples). The agreement of both methods was found: (1) 85% in patients with hematologic malignancies; (2) 100% in patients with solid tumors; (3) 97.5% in patients with primary immunodeficiency; and (4) 98.8% in patients with hereditary immunodeficiency. Overall disagreement was observed in 17 patients, in which the positive result in any of the 2 methods was estimated as true positive in conjunction with radiologic and other clinical findings.. The combination of GM and PCR, provided high diagnostic accuracy in consecutive samples (twice a week). Clinical, radiologic, and other laboratory findings should be taken into consideration in the evaluation of GM and PCR.

Topics: Adolescent; Antigens; Aspergillosis; Aspergillus; Child; Child, Preschool; DNA, Fungal; Female; Galactose; Greece; Humans; Immunocompromised Host; Immunologic Deficiency Syndromes; Infant; Male; Mannans; Neoplasms; Real-Time Polymerase Chain Reaction

Diagnosing invasive aspergillosis (IA) has long been challenging due to the inability to culture the causal Aspergillus agent from blood or other body fluids. This shortcoming has fuelled an interest in non-culture-based diagnostic techniques such as the detection of galactomannan (GM) in blood and bronchoalveolar lavage fluid, the detection of 1,3-β-d-glucan (BDG) in blood and the detection of Aspergillus DNA by PCR-based techniques. Past decades have witnessed important improvements in our understanding of the strengths and limitations of antigen assays and in the standardization of PCR-based DNA techniques. These assays are now being incorporated into care pathways and diagnostic algorithms; they help us to steward and monitor antifungal therapies and to predict treatment outcomes.

Topics: Aspergillus; beta-Glucans; Biomarkers; Bronchoalveolar Lavage Fluid; DNA, Fungal; Galactose; Humans; Immunologic Deficiency Syndromes; Invasive Pulmonary Aspergillosis; Mannans; Polymerase Chain Reaction