Ulcerative Colitis (UC) is a debilitating disease resulting in high morbidity and severely affect patients’ quality of life. Patients with UC will experience periods of remission and flare up. It is a disease affecting the colon, characterized by altered bowel habit, bloody diarrhea, abdominal pain, weight loss and anaemia. The prevalence of UC is about 200/100,000 in the west compared to 50-60/100,000 in China or Japan. Over the last decade, the prevalence has increased in the East. The cause of UC remains unknown; it is thought to be closely linked to autoimmunity to large bowel mucosal. UC can develop at any age, but peak incidence is between the ages of 20 and 30 years. It can also affect patient’s social and psychological wellbeing, if poorly managed. Currently the only way to “cure” the disease is by total colectomy which is not without its risk and complication. The understanding of cytokines and intracellular messenger pathway in UC has led to the discovery of Janus Kinase (JAK) enzymes, which is one of the area of research interest.
Alopecia Areata (AA)
Alopecia Areata (AA) is an autoimmune disease where body T cells attack the hair follicles resulting in transient non-scarring hair loss, which may last for a few weeks to decades. Alopecia Areata refers to single or multiple areas of demarcated, patchy hair loss. It is known that AA patients have a higher incidence of depression. AA affects about 2% of the population in their lifetime globally. The incidence in China is 0.27% and there are about 4 million people suffered from AA in China. 70-80% of subjects are 40 years of age or below and the incidence does not indiscriminate by sexes or ethnicity. It is thought to be due to a mixture of stress, deranged immune system and genetic predisposition. It was also found that patients with longer duration of the disease have less favorable prognosis. Currently there is no treatment that can produce permanent reversal of hair growth. There also are increasing clinical evidences that suggest JAK inhibitors could be a potential treatment for alopecia areata.
Crohn’s disease (CD)
Crohn’s disease (CD) is an inflammatory bowel disease that causes chronic inflammation of the gastrointestinal (GI) tract, characterized by its relapsing and remitting course of inflammation. The disease is progressive in some people. Its prevalence is higher in the West at about 100/100,000 compared to 20/100,000 in Japan and China. The incidence is slightly higher in women, with a peak incidence occurs at the age of between 20 to 40 years. Unlike UC which only affects colon, CD may affect any part of the GI tract from mouth to anus, with terminal ileum and proximal colon most commonly affected. It results in various symptoms including abdominal pain, bloating, diarrhoea, vomiting, and weight loss. There is yet to have cure for CD, the principles of its management aim at, halting disease progression, inducing and maintaining remission, while also preventing surgery and disease complications. The new treatments focus on inhibiting or altering T-cell differentiation.
Neuromyelitis Optica (NMO)
Neuromyelitis Optica (NMO) also known as Devic’s syndrome is a rare, chronic, autoimmune, inflammatory, demyelinating disorder of the central nerve system (CNS) that preferentially affects the optic nerves and spinal cord. Clinically it is characterized by recurrent attack of optic neuritis and transverse myelitis. Optic neuritis may result in optic pain, impaired vision leading to blindness, while transverse myelitis may cause para/tetraparesis, muscle spasms, pain, nausea, vomiting and paralysis in severe cases.
NMO has a higher prevalence among women than in men. The median age of onset is 39 years. The prevalence of NMO among Caucasians is about one to three per 100,000. Although no reliable epidemiology data, its prevalence among Chinese and Japanese is thought be higher than the West.
There are several types of immune cells important in NMO pathogenesis, including macrophages, natural killer (NK) cells, T lymphocytes, and plasmablasts. Plasmablasts (eg CD19, CD20) are responsible for the production of autoantibodies against aquaporin-4 (AQP4-IgGs) water channel. New therapies targeting B-
Atopic dermatitis (AD)
Atopic dermatitis (AD) is a chronic inflammatory skin disease posing a significant burden on health-care resources and patients’ quality of life. It is a complex disease with a wide spectrum of clinical presentations and combinations of symptoms, including patches of skin that are red or brownish, dry, cracked or scaly skin and itchy skin, especially at night.
AD affects up to 20% of children and up to 3% of adult; recent data show that is prevalence is still increasing, especially in low-income countries.
While biologics is an important addition to the treatment landscape, there remains a great need for alternative therapies for AD.
Vitiligo is a long-term skin condition characterized by patches of the skin losing their pigment. The hair and mucosa may also be involved. Typically, both sides of the body are affected; the patches begin on areas of skin that are exposed to the sun. It is more noticeable in people with dark skin. Vitiligo may result in psychological stress and those affected may be stigmatized. Globally about 1% of people are affected by vitiligo. In some populations it affects as many as 2–3%. Males and females are equally affected. About half show the disorder before age 20 and most develop it before age 40.
The exact cause of vitiligo is unknown. It is believed to be due to genetic susceptibility that is triggered by an environmental factor such that an autoimmune disease occurs.
There is no known cure for vitiligo. For those with light skin, sunscreen and makeup are all that is typically recommended. Other treatment options may include steroid creams or phototherapy to darken the light patches. Alternatively, efforts to lighten the unaffected skin, such as with hydroquinone, may be tried. Several surgical options are available for those who do not improve with other measures. A combination of treatments generally has better outcomes.