IgE anti-BP180 NC16A autoantibody in both serum and blister fluid samples does not correlate with disease activity of bullous pemphigoid

The correlation between IgE anti-BP180 NC16A autoantibody and disease activity of bullous pemphigoid (BP) remains disputable. To determine the levels of IgE anti-BP180 NC16A autoantibody and its clinical significance in untreated BP patients. IgG and IgE anti-BP180 NC16A autoantibody in serum and blister fluid samples of 34 untreated BP patients was detected by enzyme-linked immunosorbent assay (ELISA), and correlation with clinical and pathological features of BP were statistically analysed. The Bullous Pemphigoid Disease Area Index (BPDAI) was used to measure disease activity of BP. The mean baseline level of IgG anti-BP180 NC16A autoantibody in serum and blister fluid samples of untreated BP patients was 75.3 U/mL and 1.54 U/mL, respectively (A450, cutoff: 0.126). IgE anti-BP180 NC16A autoantibody was positive in 21.9% serum and 14.7% blister fluid samples of untreated BP patients. IgE anti-BP180 NC16A autoantibody levels in serum samples positively correlated with those from blister fluid samples (r = 0.983, p < 0.05). However, IgE anti-BP180 NC16A autoantibody level in both serum and blister fluid samples of untreated BP patients did not correlate with IgG anti-BP180 NC16A autoantibody, age, extent of elevated peripheral blood eosinophils, BPDAI erosion/blister score, BPDAI urticaria/erythema score, BPDAI pruritus score, BPDAI without damage score, or BPDAI total score (all p > 0.05). No significant correlation was identified between disease activity and positive or negative anti-BP180 NC16A IgE autoantibody. Conclusion: IgE anti-BP180 NC16A autoantibody in both serum and blister fluid samples does not appear to correlate with disease activity of BP.