dc.description | MS Autoimmune demyelinating disease of nerve cell in brain , spinal cord
characterized by various neurological disorders. More effect female then male ,
characterized by focal areas of white matter demyelination and gray inflammation
(1).
Brain atrophy, or brain shrinkage, is an important manifestation of multiple sclerosis
It's one of the most destructive result of the disease (1) . Brain atrophy can be seen in
the earliest stages of MS and may lead to irreversible impairments. Whereas, MRI
lesions are highly distributed in white matter (WM) and gray matter, the brain tissue
that appears in MRI is also affected by pathological studies (1). Causes of MS
(unknown) and pathogenesis are cell mediated (type TV) hyper sensitivity reaction
(2). T cell , B cell , Macrophages .
T cell : break through blood brain barrier lead to activation by myelin proteins( myelin
basic protein) , Th17 cell produced cytokines lead to the attract other leukocytes , Th1
cell produce interferon gamma lead to activation of macrophage ,so T cell produce
cytokines (IL1 ,IL6 ,TNF-alpha) that lead to oligodendrocytes damaged , blood brain
barrier express more receptors for other leukocytes , blood vessels dilate easier
passage for other leukocytes (2).
B cell: produce antibodies that bind to myelin protein and mark them(2) .
Macrophage : recognize marked oligodendrocytes , engulf them attacks occurs in 2
stage ,early stage : regulator T cell reduce inflammation lead to oligodendrocytes heal
, renew myelin (remyelination).
Later stage : repetitive extensive damage lead to death of oligodendrocytes , loss of
myelin ,damage ,loss axons . 4 types of MS: 1- Relapsing remitting multiple sclerosis
(RRMS) bouts of autoimmune attacks ,months to year ,improvement after attack .2-
primary progressive multiple sclerosis (PPMS)one constant attack lead to progression
of disabilities over lifetime. 3- secondary progressive multiple sclerosis (SPMS) start as
( RRMS) ,over time become constant lead to progression of disabilities .4- progressive
relapsing multiple sclerosis (PRMS) one constant attack , lead to faster progression of
disabilities. Risk factor of MS 1- genetic factor : individuals who are biologically
female twice as susceptible , polymorphisms of certain alleles of major
histocompatibility complex (e.g HLA DR2 : identifying, binding of foreign molecules)
.2- Environmental : infection (e.g Epstein Barr Virus infection ) , vitamin D deficiency ,
usually affects young adults. | en_US |