Characterization of latent allergen profile and association with clinical features in patients with IgG4-related disease.

OBJECTIVE

The objective of this study was to describe the IgG4-related disease (IgG4-RD) allergen profile and its clinical associations.

METHODS

One hundred patients with IgG4-RD and 40 healthy controls (HCs) were enrolled. We measured allergen-specific IgE (AsIgE) in all participants and AsIgG4 in 20 patients with higher serum IgG4 and AsIgE levels. We described the AsIgE positivity rate and allergen profiles, compared clinical parameters, and further analysed antibody correlations (AsIgE and AsIgG4) in IgG4-RD.

RESULTS

The AsIgE-positive rate in IgG4-RD patients (59%) was significantly higher than that in HCs (15%) (P < 0.001). The four most frequently detected allergens in IgG4-RD patients were house dust mites (47%), cockroach (26%), moulds (14%) and grasses (14%). Patients with positive AsIgE tended to coexist with high levels of total IgE (T-IgE) (P < 0.0001) and TNF-α (P < 0.05). Additionally, the number of detected allergens for each patient was positively correlated with serum IgG4 (P < 0.0001), T-IgE (P < 0.0001), etc., but exhibited a significant inverse correlation with complement 3 (C3) (P < 0.0001), C4 (P < 0.001), etc. Notably, cockroach-sIgE positivity showed an association with ureter (P < 0.05)/sinus (P < 0.05) involvement, while mulberry- and moulds-sIgE positivity was linked to renal (P < 0.01) and orbital (P < 0.05)/lacrimal (P < 0.01) involvement separately. Moreover, no significant AsIgE-AsIgG4 correlation was found.

CONCLUSION

Our study characterized the allergen profile in IgG4-RD patients, and reported its association with enhanced inflammation and distinct organ involvement. Non-overlapping IgE and IgG4 reactivity against allergens suggested potentially distinct cellular origins and/or induction pathways for them in IgG4-RD.