IMMUNOMODULATORS AND THEIR RECEPTORS 3976.2.1.3 IFN-γ
This glycoprotein has a molecular weight of 15,500 Da. One member of this family,
IFN-γ-1b, is 140 amino acids long and has been studied clinically as a treatment for
lung cancer and kidney cancer.
6.2.2 Clinical–Molecular Interface: Multiple Sclerosis and IFN-βCB is a 32-year-old female who presented to the emergency department with the sudden
onset of visual loss in her right eye. She was completely blind in that eye. She had previ-
ously been well, but on detailed questioning other symptoms became apparent. Three years
earlier, she had experienced numbness of her entire left leg. The problem had lasted
12 weeks, but had completely resolved. Over the past year, she had noticed that sometimes,
when she flexed her neck forward to look downwards, she would experience an “electric
shock” sensation down her back. Over the past several months, she had noticed transient
problems with double vision whenever she took a hot bath; upon getting out of the bathtub,
the double vision would promptly resolve. A clinical diagnosis of multiple sclerosis was put
forth. Laboratory support for this diagnosis was obtained when a magnetic resonance imag-
ing (MRI) scan revealed multiple areas of demyelination within the brain. Her current prob-
lem with visual loss was treated acutely with intravenous methylprednisolone. She was
then started on a regimen of IFN-βto decrease the likelihood of future exacerbations.
Multiple sclerosis is a fascinating disease that is typically treated by pharmacologi-
cal manipulation of the immune system. It most frequently affects people who live in
temperate climates (rather than from hotter, equatorial countries), or at least people who
spent their first 15 years of life in a temperate climate. Multiple sclerosis is referred to
as a demyelinating disease, because it episodically involves the patchy loss of myelin
from the brain and spinal cord. The discrete area of myelin loss is called a plaqueand
can occur in any white-matter area of the central nervous system. Since the plaques can
occur in various places in the brain and sometimes years apart, multiple sclerosis is said
to be defined by “demyelinating lesions separated in space and time.” If one regards
myelin as an insulating fat substance wrapped around axons in the brain, then demyeli-
nation causes localized “short circuits” within the brain, thereby giving rise to a wide
variety of different symptoms. Transient (8–12 weeks) loss of vision in an eye (optic
neuritis) is a frequent early symptom of multiple sclerosis. The disease is now fre-
quently treated with interferon-βor sometimes with large doses of corticosteroids to
reduce the severity of a particular exacerbation of the disease.