Pemphigus is severe antigen derived autoimmune bullous skin disorder, the word pemphigus is derived from the Greek word" pemphix " which means blister . Two main clinical variants are known pemphigus vulgaris (PV), and pemphigu foliaceus (PF). (Zenzo .et al., 2015).

Clinically, there are localized or generalized flaccid bullae that quickly transform into post-bullous erosions and crusts , PV patients characteristically develop oral lesions with buccal and/or gingival persisting erosions (mucosal dominant PV) which several weeks or months later may also spread to the epidermis (mucocutaneous PV). PF is characterized by widespread cutaneous fragile bullae which rapidly rupture, resulting in erosions, crusting, and scaling. In contrast to PV, the mucosa is usually not involved in PV. (Zenzo .et al .,2015).

Pathophysiologically, the underlying intraepithelial blister formation is caused by IgG autoantibodies against the desmosomal adhesion proteins, desmoglein 3 and/or desmoglein 1, on epidermal keratinocytes. ( Amagai .et al .,1991) In PV the antigen is desmoglein 3 which is presented in lower epidermis and is expressed more strongly in buccal mucosa than in the skin ,in contrast to PF which its antigen is desmoglein 1 which is expressed in the skin throughout the epidermis and weakly expressed in the mucous membranes . ( Kneisel and Hertl. .,2011).

T cells play a crucial role in the pathogenesis of pemphigus vulgaris , The interaction of T and B cells critically modulates the development of pemphigus vulgaris. (Amber. et al., 2013 ; Zhu, et al.,2012).

Because B-cell activation and antibody production classically necessitate the involvement of CD4+ T cells, Dsg-reactive T cells were capable of recognizing multiple epitopes of the extracellular domain of Dsg and helping B cells to produce a specific antibody. Dsg3-reactive T-cell clones were able to commit polyclonal naive B cells to produce pathogenic anti-Dsg3 antibody and induce the PV phenotype. (Hertl . et al., 1998) Follicular T helper cells (Tfh) are a recently discovered group of CD4+ Th cells with intrinsic differences from Th1, Th2 and Th17 cells. Localized in B-cell follicles of secondary lymphoid tissues, The major function of Tfh cells appears to help B-cell activation and antibody production during humoral immune responses. The Tfh cells express high levels of IL-21, which was demonstrated to be important for the generation of Tfh cells and that responsiveness of Tfh cells to IL-21 drives the formation of the autoimmune reaction, and it clearly impacted on the amount of antibody production.( Gomez. et al.,2011 ; Vogelzang . et al.,2008) Nowadays, finding a promising treatment for pemphigus remains a serious challenge. Various treatments are currently recommended to treat this disease, but they rarely lead to complete and durable remission. Regulatory cells appear to have a critical role in numerous autoimmune diseases, so it is possible that control of these cells may induce remission. (Cholera and Chainani .,2016)

Inclusion Criteria:

• 20 pemphigus vulgaris patients
• healthy age and sex matched

Exclusion Criteria:

• - Patients with a history of topical or systemic treatment (corticosteroids, intralesional steroid injection, immunosuppressive therapy, anticonvulsants and anticancer medications, within 4 weeks of the study.
• Patients receiving phototherapy within 6 months of the study .
• Patients with a history of diabetes mellitus, anemia, thyroid or parathyroid disorders, chronic liver or renal diseases, or atopy .
• Patients with known autoimmune diseases or cancer.
• Pregnant or lactating women were also excluded from the study.

20 pemphigus vulgaris patients will be included in the study, either newly diagnosed or recurrent. Patients will be recruited on admission from Dermatology department and Outpatient Clinic, Assiut University Hospitals. 10 healthy age and sex matched subjects will be included as controls.