302 Screening for Allergic Bronchopulmonary Aspergillosis in Patients with Aspergillus + Asthma From 2000 to 2010

BACKGROUND: Approximately 25% of patients with persistent asthma have immediate skin reactivity to Aspergillus species. The purpose of this study was to screen all patients with immediate hypersensitivity to Aspergillus for evidence of Allergic Bronchopulmonary Aspergillosis (ABPA). METHODS: All patients with asthma underwent immediate cutaneous testing including prick (epicutaneous) with a mix of Aspergillus species and if negative, intradermal at 1000 PNU/mL, Aspergillus fumigatus (Af). Sera were analyzed for total IgE (elevated is ≥417 kU/L) by Phadia ImmunoCap, anti-Af IgE and anti-Af IgG (ABPA range ≥ 2.0) ELISA, and precipitating antibodies. HRCT of the lungs was ordered next if serology was positive (diagnostic criteria for ABPA required total IgE ≥ 417 kU/L and both anti-Af IgE and IgG ≥ 2.0 compared to sera from skin test + patients with asthma without ABPA). To avoid bias from patients examined by the author, data were compared using screening from 5 other faculty in the same clinic. RESULTS: From 2000 to 2010, 864 skin test + patients underwent serologic testing for ABPA from which 81 (9.4%) were diagnostic for ABPA, and in this group, precipitins were positive in 42/81. To address referral bias in screened patients of the author, diagnostic criteria were positive in 49/208 (23.5%) patients of the author versus 32/656 (4.8%) of other allergy-immunology faculty. In addition, some 74/884 (8.6%) patients had total IgE ≥ 417 kU/L and either anti-Af IgE or IgG ≥ 2.0, implying an overall at risk for ABPA population of 155/864 (17.9%). The highest total IgE recorded in a non-ABPA patient with asthma was 192,100 kU/L. CONCLUSIONS: Using total IgE and ELISA determinations to discriminate ABPA from skin test + asthma sera, 9.4% of patients had diagnostic evidence for APBA. Using data from faculty, presumably with less referral bias than the author, results in 4.8% patients with classic diagnostic criteria. This rate conservatively translates into a minimum of approximately 1.2% of patients with persistent asthma having APBA in the upper Midwestern US. The combination of elevated total IgE and precipitins but not elevated anti-Af IgE or IgG in this population has little/no value in diagnosis.