ABSTRACT
The complement system is a self-protection mechanism of the human body. The abnormal activation of the complement system is involved in the occurrence and development of various diseases. The application of complement inhibitors in many rare diseases was a milestone in leading to the progress of such disease as paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS), and others. Recently, the application of complement inhibitors has gradually expanded to other complement-related diseases. This review summarizes the literature on the current application of complement inhibitors in rare diseases and looks into the prospects of the application in the rare diseases.
ABSTRACT
The complement system is known to be involved in the pathogenesis of the skin lesions in pernphigus vulgaris, bullous pemphigoid, dermatitis herpetiformis, epidermolysis bullosa acquisita, and systemic lupus erythematosus. Authors examined the skin specimens of each disease cases, who did not show any evidence of complement deficiency, to determine the deposition of complement components(C4, C3, Chb-9) and their inhibitors(C4bp, Factor H, S-protein) by modified direct immunofluorescence. We also looked at the staining pattern and localization, for further insights of their pathobiologic contributions in each disease. The findings of deposits of complement components up to C9, as well as inhibitor proteins at the primary histopathologic sites, in the majority of those cases, may indicate that the complement system, to certain extent, involves the inflamrnatory reactions in these diseases. The co-localization of C5b-9 and S-protein could be regarded as the consequence of in situ formation of SC5b-9 complexs or as the result of non-lytic adsorbed complexes of fluid phase SC5b-9. The pathologic role of the complement seems to depend mostly on the complement-fixing biologic property and the amount of the tissue bound immune complexes, which are often heterogeneous to different diseases and among different patients.