Role of real time PCR and specific IgG in identifying patients with Aspergillus colonisation

C.G. Baxter, A.M. Jones, K. Webb, A. Moody, S. Follett, D.W. Denning

Research output: Contribution to conferenceOther

Abstract

Purpose Aspergillus fumigatus colonisation is common in CF but prevalence varies between studies from 12-57%. Colonised patients are not routinely treated with antifungals. This study aimed to accurately identify patients with A.fumigatus colonisation using Real time PCR and examine the relationship to markers of sensitisation. Methods 49 adult CF patients provided a sputum sample, a blood sample for Aspergillus serology and had fungal skin prick tests. Serological tests included total IgE, specific IgE A.fumigatus and specific IgG A.fumigatus performed by Phadia ImmunoCAP® assay, and A.fumigatus precipitins by counterimmunoelectrophoresis. A commercial Real time PCR kit, MycAssay™ Aspergillus, was used to detect Aspergillus in CF sputum samples. Results 15 of the 49 sputum samples were PCR positive for Aspergillus species. All PCR positive samples had a positive specific IgG titre (>40mg/L) but 41% of PCR negative samples also had a positive IgG titre. PCR positive patients had a significantly greater mean specific IgG Aspergillus (PCR positive 93mg/L SE 6.74 versus PCR negative 47mg/L SE 4.44 p= <0.001). Using a ROC curve, an IgG level above 67mg/L gives 85% sensitivity and 90% specificity for positive PCR. No other marker of A.fumigatus sensitisation correlated to positive PCR. Conclusion Real time PCR can be used to identify patients colonised or infected with Aspergillus, including those in whom antifungal therapy is inadequate. A specific IgG titre above 67mg/L correlates with finding Aspergillus in the bronchial tree by PCR. Additional data are required to determine which marker(s) is most useful for treatment decision-making.
Original languageEnglish
PagesS35-S35
Publication statusPublished - Jun 2010
Event33rd European Cystic Fibrosis Conference - Valencia, Spain
Duration: 1 Jan 1824 → …

Conference

Conference33rd European Cystic Fibrosis Conference
CityValencia, Spain
Period1/01/24 → …

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