Skin inflammatory diseases, medically referred to as
‘dermatitis’, is a common skin allergic disease of the third world countries. Causes
of dermatitis are still not known but a lot of genetic and environmental
factors have been implicated in the pathogenesis.
The extent of dermatitis can be localized or extensive.
Primarily characterized by reddened skin, itchiness, rashes, sores along with dry
skin and trans-epidermal water loss, it can affect at any age and is primarily
thought to be caused by a defect in the barrier of the skin that makes an
individual susceptible to environmental allergens. Psoriasis is thought to be
genetically predisposed and triggered by environmental factors and can affect a
person at any age. It is an autoimmune disease wherein the immune cells
generate immune response against skin cells and is characterized by
hyper-proliferative skin (psoriasis vulgaris).
IL-9 is a cytokine belonging to the IL-2 family. TGF-?
and IL-4 induces production of IL-9 by the CD4+ T lymphocytes following the
Th-9 pathway. In the aforementioned diseases, studies have shown increased expressions
of Th-9 cells and subsequently a significantly increased IL-9 expression.
A lot of speculations have been made on the possible
roles of IL-9 in the disease pathogenesis but as a whole its role is not yet
known. Since IL-9 has been found in such high quantities in the lesional skin
of patients with AD and Psoriasis, it is stated in various research studies that
it might play a significant part in the progression of these diseases.
Targeting IL-9 could be the next way to tackle such
diseases but it hasn’t been reported yet. Thus, it becomes necessary to
elucidate its downstream function so that the pathogenesis can be well understood
and new therapeutic avenues can be traversed in order to take preventive
actions against such skin inflammatory diseases.