Bullous pemphigoid anti-BP180-NC16A autoantibody reactivity in healthy individuals is associated with marked hypovitaminosis D and Th2-like cytokine predominance

Abstract

Autoimmune bullous disease autoantibodies, particularly including bullous pemphigoid (BP)-related anti-BP180-NC16A IgG, have been reported in a small subset of healthy individuals, but information about associated factors is lacking. We hypothesized that an abnormal status of immunomodulatory vitamin D could play a role in anti-BP180-NC16A autoantibody reactivity in healthy persons. In addition, we aimed to evaluate the cytokine profile associated with these autoantibodies. Plasma samples from 34 anti-BP180-NC16A IgG-reactive and 85 anti-BP180-NC16A IgG-negative healthy blood donors were tested for levels of 25-hydroxyvitamin D [25(OH)D] and a wide range of cytokines (IL-2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-13, IL-17A, IL-17F, IL-21, IL-22, IFN-γ, and TNF-α). We observed that anti-BP180-NC16A IgG-reactive healthy subjects had significantly lower plasma 25(OH)D levels and about a two-fold higher rate of vitamin D deficiency (< 20 ng/ml) compared to anti-BP180-NC16A IgG-negative healthy persons. In addition, anti-BP180-NC16A IgG-positive samples were characterized by significantly higher levels of IL-2, IL-5, IL-9, IL-10, and IL-13 which were, however, not significantly associated with the vitamin D levels. Our results indicate that healthy individuals with BP autoantibody reactivity share similarities with BP patients regarding the vitamin D status and cytokine profile (i.e., marked hypovitaminosis D and Th2 predominance), which may have pathophysiologic implications.

Keywords: 25(OH)D; Bullous pemphigoid; Cytokine; Th2; Vitamin D.

Fig. 1

Anti-BP180 autoantibody reactivity in healthy individuals is associated with marked hypovitaminosis D. Plasma 25-hydroxyvitamin D [25(OH)D] status of anti-BP180-NC16A IgG-positive (n = 34) and anti-BP180-NC16A IgG-negative (n = 85) healthy individuals measured by enzyme-linked immunosorbent assay. 25(OH)D plasma levels of ≥ 30 ng/ml, 20–29 ng/ml, and < 20 ng/ml were considered sufficient, insufficient, and deficient, respectively. The squares/dots and bars indicate individual and mean (± SEM) values in each group, respectively. *P < 0.05

Fig. 2

Anti-BP180 autoantibody reactivity in healthy individuals is associated with Th2 predominance. Plasma levels of IL-2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-13, IL-17A, IL-17F, IL-21, IL-22, IFN-γ, and TNF-α in anti-BP180-NC16A IgG-positive (n = 34) and anti-BP180-NC16A IgG-negative (n = 85) healthy individuals measured by flow cytometry. The squares/dots and bars indicate individual and mean (± SEM) values in each group, respectively. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. ns not significant

Fig. 3

Hypovitaminosis D is not correlated with the Th2-dominant milieu in anti-BP180-NC16A IgG-positive healthy subjects. Heatmap matrix plot of Spearman’s rank correlation coefficients (r) between plasma levels of 25(OH)D, IL-2, IL-5, IL-9, IL-10, and IL-13 in either anti-BP180-NC16A IgG-negative or anti-BP180-NC16A IgG-positive healthy individuals. R values are presented in boxes and significant correlations are indicated by asterisks. *P < 0.05