1. Pemphigoid:

2. Mucous membrane pemphigoid (MMP) is chronic blistering or vesiculobullous disease that affects predominately oral and ocular mucous membranes.
an autoimmune disease (autoimmune reaction
to basement membrane protein )
with an unknown stimulus.
Deposition of Ig and complement component along the basement membrane zone ( on DIF testing ) are characteristic.

3. When it is affects gingiva called desquamative gingivitis.

7. Histopathology:
MMP is a subepithelial clefting disorder and there is no acantholysis.
In early stages few lymphocytes are seen, but with time the infiltrate becomes more dense and mixed.

8. Direct immunofluorescence studies
a continuous linear band of immunoreactantsat the basement membrane zone in nearly 90% of affected patients
IgG and C3, although IgA and IgM
Indirect immunofluorescence is positive in only 5% of these patients