23 Seasonal variation in Aspergillus specific antibody levels – does weather influence exposure?

Abstract

Objective ABPA is an important complication of pulmonary disease in CF patients, quoted as occurring in 5–15% of patients. We speculated that environmental exposure varies with weather conditions and so sought to look for variations in Aspergillus specific IgG level according to time of year and seasonality. Methods Of 282 adult CF patients, we selected the 152 (54%, mean age 29 years [range 18–69], 89 male) with heightened Aspergillus sensitivity ( Aspergillus specific IgG levels above the normal range (40 mg/ml)) and recorded these per month for the years 2009–2014. The exercise was repeated for those 48 patients with a clinical diagnosis of allergic bronchopulmonary aspergillosis (mean age 29 years [18–57], 26 male; 32% of those with raised specific IgG). Results Aggregated results showed a trend towards higher Aspergillus specific IgG levels in the Spring months in both groups, when the weather in this part of the UK tends to be mild and wet. Conclusion The increased sensitivity to Aspergillus in CF patients in the mild and wet Spring months suggest that these conditions favour the growth of Aspergillus fumigatus . This would suggest that we might see a rise in symptomatic ABPA at this time of year, and explain why we have higher than quoted proportion of CF patients with ABPA.