Anti-BPIFA1/SPLUNC1: A new autoantibody prevalent in patients with endstage cystic fibrosis

BackgroundBactericidal/permeability increasing protein fold containing family A (BPIFA) 1, is a secreted protein of the upper airways that shares structural homology with BPI and exhibits comparable antimicrobial capacities. We hypothesized that CF patients have circulating IgG or IgA anti-BPIFA1 autoantibodies, similarly as reported for BPI autoantibodies.MethodsWe analyzed pre- and post-transplantation sera from 67 endstage lung disease patients who underwent lung transplantation (LTx) because of COPD (n = 27), CF (n = 25), and ILD (n = 15).ResultsAnti-BPIFA1 (48%) and anti-BPI (92%) were elevated in CF patients compared to healthy controls, with anti-BPIFA1 IgG isotype being most prevalent, whereas anti-BPI is of the IgA isotype. Levels of anti-BPI autoantibodies significantly declined post-LTx, whereas anti-BPIFA1 did not. No relation was found between autoantibodies against BPIFA1 and BPI.ConclusionOur results indicate that BPIFA1 is a novel target for autoantibodies in CF. The function of these autoantibodies needed to be investigated in future studies.