Evidence of platelet activation in multiple sclerosis.
OBJECTIVE
A fatality in one multiple sclerosis (MS) patient due to acute idiopathic thrombocytopenic purpura (ITP) and a near fatality in another stimulated our interest in platelet function abnormalities in MS. Previously, we presented evidence of platelet activation in a small cohort of treatment-naive MS patients.


METHODS
In this report, 92 normal controls and 33 stable, untreated MS patients were studied. Platelet counts, measures of platelet activation [plasma platelet microparticles (PMP), P-selectin expression (CD62p), circulating platelet microaggragtes (PAg)], as well as platelet-associated IgG/IgM, were carried out. In addition, plasma protein S activity was measured.


RESULTS
Compared to controls, PMP were significantly elevated in MS (p < 0.001) and CD62p expression was also markedly elevated (p < 0.001). Both are markers of platelet activation. Platelet-associated IgM, but not IgG, was marginally elevated in MS (p = 0.01). Protein S in MS patients did not differ significantly from normal values.


CONCLUSIONS
Platelets are significantly activated in MS patients. The mechanisms underlying this activation and its significance to MS are unknown. Additional study of platelet activation and function in MS patients is warranted.
Sheremata
William A
WA
Multiple Sclerosis Center and Department of Neurology Miller School of Medicine, University of Miami, Miami, Florida, USA. sheremaw@bellsouth.net
Jy
Wenche
W
Horstman
Lawrence L
LL
Ahn
Yeon S
YS
Alexander
J Steven
JS
Minagar
Alireza
A
D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D009103:Multiple Sclerosis / Q000097:blood*; D019007:P-Selectin / Q000097:blood / Q000502:physiology; D015539:Platelet Activation / Q000502:physiology*; D010974:Platelet Aggregation; D010976:Platelet Count; D017293:Protein S / Q000378:metabolism; D012016:Reference Values
D007074:Immunoglobulin G; D007075:Immunoglobulin M; D019007:P-Selectin; D017293:Protein S