Linear IgA bullous disease (LABD) is a nonhereditary, autoimmune subepidermal bullous disease, characterized by the presence of continuous linear deposits of IgA autoantibodies along the basement membrane zone. The disease affects both children and adults and, although there are some differences in their clinical presentations, there is considerable overlap with shared immunopathology and immunogenetics. LABD is a unique immunobullous disease characterized by vesicles, bullae, and erosions. Due to the complex pathogenesis of BP, the multifaceted complexity of upstream and downstream mechanisms implied in the pathogenesis of BP remains an area of intense speculation. However, IgA autoantibodies are considered an important factor involved in disease pathogenesis and could be detected in the skin or serum of LABD patients. Therefore, Creative Biolabs established mature IgA research platforms and we are glad to share our experience about LABD and IgA with our partners over the world.
Clinical Presentation of Linear IgA Bullous Disease
Fig.1 Linear IgA deposition along the basement membranezone in perilesional skin. (Patsatsi, 2013)
LABD with adult and of childhood share the same basement membrane zone antigens and thus, they are currently considered as variants of the same disease. However, children with LABD show differences in clinical presentation compared with adults, reflected in the common usage of the term chronic bullous disease of childhood. The “cluster of jewels” pattern is typical of LABD. In this pattern of distribution, tense vesicles arise at the periphery of old lesions, whose predilection sites are the lower extremities. Adults with LAD have an increased incidence of lymphoproliferative disorders such as bladder and renal cancer. Moreover, LAD has been associated with both ulcerative colitis and Crohn’s disease in small numbers of patients, all of which are autoimmunity diseases.
Pathogenesis of Linear IgA Bullous Disease
LABD is an autoimmune disease with the targeted antigens localized in the basement membrane of the squamous epithelium. Antigens mainly involved in the pathogenesis of CBDC are a 97-kDa (LABD97) and a 120-kDa (LAD-1) antigen, which represents fragments of the extracellular domain of collagen XVII (BP180), a transmembrane protein playing a critical role in maintaining the linkage between the intracellular and the extracellular structural elements involved in epidermal adhesion. Production of IgA against the above antigens and deposition in a linear pattern along the basement membrane determines the humoral response in CBCD. The cellular response is also involved with complement activation, recruitment of inflammatory cells, and release of proteolytic enzymes. Therefore, LABD is typically associated with IgA on immunofluorescence testing.
Fig.2 Collagen XVII and other components of the dermo-epidermal junction adhesion complex. (Venning, 2011)
Treatment of Linear IgA Bullous Disease
LABD is a recurrent disease with the potential to become generalized or severely affect mucosa, especially the conjunctiva. Dapsone is used as first-line therapy in the treatment of LABD in adults, while dapsone may be combined with oral steroids. However, due to the adverse effects, dapsone was gradually replaced by numerous other treatments which have been reported to be effective in the treatment of LABD such as therapeutic monoclonal antibodies, antibiotics, and intravenous immunoglobulins.
Because of the rapid development of biotherapy of LABD, therapeutic antibodies and biological agents show more application potential in autoimmune diseases treatment. If you are interested in the research of LABD, or want more details in the research of the therapeutic molecular field, please feel free to contact us.
References
- Patsatsi, A.; et al. Chronic bullous disease or linear IgA dermatosis of childhood-revisited. J Genet Syndr Gene Ther. 2013, 4(6), 1-5.
- Venning, V. A.; et al. Linear IgA disease: clinical presentation, diagnosis, and pathogenesis. Dermatologic clinics. 2011, 29(3), 453-458.
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