Bullous pemphigoid and mucousa membrane pemphigoid (MMP) are autoimmune blistering diseases that commonly arise in the older adults. These disorders are characterized by subepithelial blister formation and also percipitation of immunoglobulins and complement in the epidermal and/or mucosal basement membrane zone.
Although both bullous pemphigoid and MMP may affect skin and mucosa, the classical clinical manifestations in bullous pemphigoid are tense, fluid-filled bullae on skin whereas the prevailing clinical feature in MMP is mucosal involvement. In MMP, inflamed and eroded mucosa is characteristic, involving any or all of the oral cavity, ocular conjunctiva, nose, pharynx, larynx, esophagus, anus, and genital mucous membranes.
Panel test:
• Immunopathology:
oCutaneous Direct Immunoflourescence, Biopsy
oCutaneous DIF
oEER cutaneous DIF
Note: DIF includes IgG, IgG4, IgM, IgA, C3, and fibrinogen with diagnostic interpretation of staining patterns
Comments: DIF and IIF show mainly linear IgG and C3 at the dermo-epidermal junction, binding to the epithelial side of the basement membrane (on a saline-split preparation). Rate of positivity in DIF is up to 90% and for IIF up to 70%.
• Immunogenetics
o Increased prevalence of HLA DQB1*0301.
oBPAg1, 230kDa (chromosome 6)
oBPAg2, 180kDa (chromosome 10).
Comments: BPAg1 is like to desmoplakin I and is likely to form part of the hemi-desmosome, which provides the major site of attachment between the internal cytoskeletal proteins and the external matrix. Antibodies to BPAg1 are only detect in bullous pemphigoid. BPAg2 is also a hemi-desmosomal protein, but antibodies are also detecting in herpes gestationis.
