IOSR Journal of Dental and Medical Sciences (IOSR-JDMS) e-ISSN: 2279-0853, p-ISSN: 2279-0861.Volume 16, Issue 3 Ver. XI (March. 2017), PP 64-68 www.iosrjournals.org DOI: 10.9790/0853-1603116468 www.iosrjournals.org 64 | Page Molecular Biology: A Milestone to Diagnosis of Vesiculobullous Lesion Dr. Soumendu Bikash Maiti 1 , Dr. Nilotpol Kashyap 2 , Dr. Brij Kumar 3 , Dr. Neelam Dewani 4 1 Senior Lecturer, Department of Oral Medicine and Radiology, Pacific Dental College and Research Center, Udaipur 2 Professor and Head of the Department, Pedodontics and Preventive Dentistry, Rungta College of Dental Sciences and Research, Bhilai 3 Post Graduate Student, Rungta College of Dental Sciences and Research, Bhilai 4 Post Graduate Student, Rungta College of Dental Sciences and Research, Bhilai Abstract: Vesiculobullous lesion are group of disorders clinically manifests as formation of blisters which can either be vesicles and bulla. They pose a diagnostic challenge due to their similar or polymorphic clinical signs and symptoms and histological limitations and unpredictable progress of the lesions. Molecular biology which deals with the study of biology at molecular level provides a link between clinical and histological presentations. Pemphigus group of diseases are characterized by auto antibodies directed against desmosomal proteins. Pemphigoid group of lesions is characterized by circulating IgG autoantibodies against either BP 230 (BPAg1) and BP 180 (BPAg2) basement membrane zone proteins. Dermatitis herpetiformis is characterized by granular IgA deposits in dermal papiila whereas LINEAR IgA bullous dermatosis is characterized by IgA antibodies against 97 kDa protein (LABD 97) AND 120 kDa proteins. In epidermolysis bullosa aquisita autoantibodies are directed against type VII collagen fibres which is different from dystrophic epidermolysis bullosa characterized by mutation in type VII collagen. Keywords: Vesiculobullous lesions, pemphigus, pemphigoid, dermatitis hepetiformis, Linear IgA bullous dermatosis, epidermolysis bullosa aquisita I. Introduction Mucocutaneous vesiculobullous lesions are affected by number of autoimmune and pathologic conditions. The proper treatment of these lesions relies on accurate diagnosis and understanding of the lesions at clinical, histopathological and molecular level. These lesions present themselves with diverse clinical signs and symptoms which poses a difficulty in diagnosing the lesion. 1 Histological presentations has definite limitations due to a great polymorphism of these disorders. For eg: the acantholysis is recognized as a basic diagnostic criterion of pemphigus. along with “Tzanck test”. But acantholysis may occur in some hereditable diseases (Hailey-Hailey disease, Darier’s disease) and single acantholytic cells could be found in several diseases showing polymorphism nature of such lesions and histological limitations. 2 Autoimmune disorders like pemphigus, pemphigoid etc are group of diseases characterized by immune mediated attack against body’s self proteins or self antigens and these lesions usually are undetected before appearance of any clinical signs and symptoms and finally leading to destruction of epithelial structure. Molecular biology has put new insights into the understanding of these lesions at molecular level supplementing the histopathological findings and thereby devising the treatment plan based on this phenomenon. 3 Moreover with the development of immunofluorescent techniques which includes both direct and indirect immunofluorescene molecular biology has resulted in the recognition of several new blistering diseases and classification based on clinical, histologic, and immunologic features. For understanding of the molecular biology understanding of the epithelial biology is quintessential. 2 Epithelial Biology (Desmosomes, Epithelial Basement Membrane Zone ) Desmosomes and its proteins They are anchoring junctions to which intermediate proteins like keratin filaments bind. The transmembrane proteins of desmosomes are desmogleins (Dsg) and desmocollins (Dsc) of cadherin family, desmoplakin (DP) and plakoglobin (Pg), are the intracellular attachment protein in the desmosomes which mediate the interaction of keratin filaments with the cytoplasmic regions of desmocollins and desmogleins. (FIG 1 & 2) 4