B Cell Activating Factor of the TNF Family (BAFF) in Allergic Bronchopulmonary Aspergillosis (ABPA) and Cystic Fibrosis (CF)

Abstract

Since total and anti-A. fumigatus IgE and IgG can be increased or normal depending on disease activity, we measured serum BAFF in ABPA and CF. We hypothesized that BAFF would be elevated in sera from patients with ABPA compared to patients with fungal (A.fumigatus +) asthma. Serum BAFF was measured by ELISA (R & D Systems, Minneapolis, MN) with lowest concentration of detection of 31 pg/ml. Sera were from pooled sera from non-atopic patients, patients with A.fumigutus + asthma without ABPA, individual ABPA, and cystic fibrosis sera (with sensitization to A.fumigatus but low total serum IgE concentrations). Serum BAFF was elevated in pooled sera from ABPA (1150 pg/ml) compared to pooled sera from A.fumigatus + asthma (817 pg/ml) and sera from non-atopics (883 pg/ml). ABPA sera (n =13; 945 ± 407 pg/ml) were less than non-ABPA CF sera (n = 8:1851 ± 849 pg/ml), p < 0.01. To explore the relationship between BAFF and total IgE in ABPA (n = 13, total IgE 2970 ± 1280 kU/L) vs. CF without ABPA (n = 8, total IgE 181 ± 224 kU/L), we selected sera with equally strongly positive serum anti-A.fumigatus IgE and IgG antibodies. There was an inverse relationship between total serum IgE and serum BAFF (Spearman -0.574, p < 0.01) despite elevated anti A.fumigatus antibodies. 1. Serum BAFF was elevated in ABPA as compared to A.fumigatus + asthma and controls. 2. BAFF was greater in sera from CF compared to ABPA despite much lower total IgE concentrations in CF. 3. BAFF was inversely correlated with the total IgE concentration.