Research Projects

Bullous pemphigoid (BP) and Mucous Membrane Pemphigoid (MMP) are two common Autoimmune Bullous Diseases (AIBD). Apart from the fact that MMP is more prone to involve mucosae and result in mucosal fibrosis, there may be a clinical overlap between the two. Almost 65% of MMP patients can have ocular involvement, which can lead to conjunctival fibrosis in the early stages that can eventually result in blindness. It is unclear why ocular fibrosis is specific in MMP but not in BP, despite sharing a common antigen (BP 180) and comparable autoantibody profile. About 71% of MMP and BP patients were identified to have IgG autoantibody against BP180, the most common target antigen in both conditions. Autoantibodies against laminin 332 are detected only in MMP patients (approximately 21%). It is not yet known why mucosal fibrosis and fibrosis occur in MMP and not in BP, even though there is a significant commonality in the target antigen and the pathogenic antibody. This led us to hypothesize that “Genetic variants of BP-180 or Laminin 332 that express or present differently in BP and MMP patients might be responsible for ocular fibrosis characteristic of MMP via disrupting their protein-protein interaction”. To achieve this, whole exome sequencing of DNA from the patient’s skin biopsy will be done. Identified genetic variants will be validated using an allelic discrimination assay and autoantibody titer will be measured by ELISA. Further, the identified mutation will be cloned and transfected into HaCat cell lines for in-vitro studies and protein-protein interaction studies will be done using immunoprecipitation assay and proximity ligation assay. Further, the determination of the level of fibrosis markers such as m-CSF, CTGF, HSP47, MITF, IL-13, TNF-alpha and matrix metalloproteinase-37 at mRNA (by RT-PCR) and protein level (by Western Blot) will be done to establish the fibrogenic potential of the genetic variant. The proposed study will lead to the identification of novel genetic variations in both BP and MMP patients that can be utilized in clinical settings for better diagnosis and proper characterization of patients suffering from autoimmune blistering disorders. A better understanding of the mechanism for fibrosis will help in better management of fibrosis as well as better genetic diagnosis. The functional characterization may also help in explaining the genetic variant as a factor for fibrosis induction in MMP patients. Further exploitation of this arm may lead to therapeutic strategies reducing fibrosis.