The Distribution Of IgG Subclasses In The IgG-related Bullous Diseases

[Background] Ig G-related skin bullous disease is a group of autoimmune bullous diseases with the pathogenic Ig G antibodies to the autoantigens of the skin. pemphigus vulgaris and bullus pemphigoid are the most common diseases of pemphigus and pemphigoid. Ig G and Ig G subclasses play a key role in the genesis and development of these diseases. The distribution of Ig G subclasses is crucial to the diagnosis,treatment and prognosis of the Ig G-related skin bullous disease. It’s still not clear about the relationship between Ig G subclasses and pathogenesis.[Objective] To study the expression of Ig G-4 subclasses, C3 d and C4 d in the pemphigus vulgaris and bullous pemphigoid, the relevance of these makers with the morphology of the diseases, and to discuss the role of Ig G subclasses, C3 d and C4 d in the pathogenesis of PV and BP.[Methods] To analyze the clinicopathologc features, as well as the staining patterns of Ig G subclasses, C3 d and C4 d through direct immunofluorescence(DIF) and HE staining.[Results]1. The similar morphological features of PV and BP: hyperkeratosis and parakeratosis of the top of the blister, inflammation in the blister, edema of the dermis, the infiltration of lymphocyte, neutrophil, eosnophils and a small amount of plasmocyte and so on. 2. The different morphological features of PV and BP: the blister intra-epithelial, acantholysis cells in the blister, hair follicles involvemet, “tombstone”like cells and villous structure were obvious more common in PV; The blister under-epithelial, the edge, degeneration and necrosis of the top of blister, eosinophils sponge edema, inflammation in the blister and the infiltration of eosinophils were more often foundin BP, and the degree of inflammation in the blister was more serious in BP. 3. The similar immunological features of PV and BP: in most cases, Ig G1-3 subclasses were deposited with C3 d and/or C4 d. more than 1/3 of PV and BP were Ig G4 deposited without other Ig G subclasses. The order of positive rate of Ig G subclasses in BP and PV was the same, and the positive rate of C3 d and C4 d was similar. 4. The different immunological features of PV and BP: Ig G, Ig G1-4 subclasses and complement C3 d and C4 d were deposited on the surface of keratinocytes in the PV, characterized by the grid positive between epidermal cells;Ig G, Ig G1-4 subclasses and complement C3 d and C4 d were linear positive along the basement membrane.[Conclusions]1. IgG4 is the main Ig G subclass in PV and BP; Complement activation pathway and the complement-independent pathway are both involved in the pathogenesis of PV an BP. 2. We propose that PV and BP maybe the different subtypes of the same disease based on the overlap of the clinical manifestations, the cross of the morphological features and the similarities of the immunological manifestations. It’s necessary to detect the gene phenotypes of desmosome and hemidesmosome, SNPs, the expression of m RNA and micro RNA and related proteins to prove our hypothesis.