Serum Interleukin -21 Level in Patients With Severe Adverse Cutaneous Drug Reaction and Correlation With Disease Severity.

Erythema multiforme is an acute immune mediated disorder It is a type IV hypersensitivity reaction leading to dermal vasculitis. Erythema multiforme major usually as a result of medications such as sulphonamides, non-steroidal anti-inflammatories and penicillin and there is skin and mucosal involvement.

Steven-Johnson syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are considered a spectrum of acute life-threatening mucocutaneous reactions that differ only in severity. Both diseases are characterized by mucous membrane and skin involvement, are often caused by medications and are collectively known as epidermal necrolysis or scalded skin syndrome.Stevens-Johnson syndrome (SJS) is classified as an epidermal loss <10% of the body surface area.Toxic Epidermal Necrolysis (TEN) is indicated by >30% body surface area erosion. The range of epidermal loss between 10% and 30% is called Stevens-Johnson syndrome-Toxic Epidermal Necrolysis (SJS-TEN) overlap. Severity of illness score [Score of Toxic Epidermal Necrolysis(TEN) ] has been devised to predict prognosis in patients with Epidermal Necrolysis.This scoring system addresses 7 prognostic factors: age, malignancy, heart rate,Body Surface Area involved, serum urea, serum glucose and serum bicarbonate levels.

Interleukin-21 regulates both innate and adaptive immune responses and it is not only has key roles in antitumour and antiviral responses that promote the development of autoimmune diseases and inflammatory disorders. It is recently discovered member of the type 1 cytokine family which is produced by activated clusters of differentiation 4+ T cells ,Natural killer cells and follicular helper T cells.