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#Post#: 230--------------------------------------------------
Tysabri & JC virus infection
By: agate Date: March 25, 2014, 2:30 pm
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From Medical News Today, March 24, 2014:
[quote]Natalizumab treatment in patients with multiple sclerosis
associated with JC virus infection
Treatment with natalizumab in patients with multiple sclerosis
(MS) appears linked with JC virus (JCV) infection, which can
lead to a rare and often fatal demyelinating disease of the
central nervous system called progressive multifocal
leukoencephalopathy (PML) that destroys the myelin that protects
nerve cells. The movement of cells with JC virus into the blood
stream may provide researchers with a possible reason why
patients with MS develop PML.
Since natalizumab was reintroduced as a biologic therapy for MS
in 2006, more than 440 cases of PML have been reported. Risk
factors associated with development of PML include receiving 24
or more natalizumab infusions, receiving other immunosuppressive
treatments and testing positive for JCV antibodies in a blood
test.
The authors evaluated 49 patients with MS and 18 healthy
volunteers by drawing blood samples and examining CD34+ cells
from the bone marrow plus CD19+ and CD3+ cells. Among the 49 MS
patients, 26 were beginning natalizumab therapy. For these
patients, blood was drawn at baseline and again at approximately
three-month intervals to 10 months. Blood also was drawn on a
single occasion from 23 patients with MS receiving natalizumab
for more than two years and from the 18 healthy volunteers.
Of the 26 patients beginning natalizumab therapy, 50 percent had
detectable JC virus DNA in at least one cell subtype at one or
more measures. Among the 23 patients who received natalizumab
treatment for two years, 10 patients (44 percent) had detectable
viral DNA in one or more cell subtype, as did three of the 18
healthy volunteers (17 percent). Of the 49 total patients with
MS, 15 (31 percent) were confirmed to have JCV in CD34+ cells
and 12 of the 49 (24 percent) had it in CD19+ cells.
"We detected JCV DNA within the cell compartments of
natalizumab-treated MS patients after treatment inception and
after 24 months. The JCV DNA may harbor [live] in CD34+ cells in
bone marrow that mobilize into the peripheral circulation at
high concentrations. Cells with latent infection initiate
differentiation to CD19+ cells that favor growth of JCV.
Continued studies are needed to further investigate natalizumab
treatments as the mechanism of PML."
References
JAMA Neurol. Published online March 24, 2014.
doi:10.1001/.jamaneurol.2014.63.
The authors made conflict of interest disclosures. The study was
supported by the Division of Intramural Research funds (National
Institute of Neurological and Communicative Diseases and
National Institute of Allergy and Infectious Disease
laboratories) and other sources. ...
Article adapted by Medical News Today from original press
release.
[/quote]
The article can be seen here
HTML http://www.medicalnewstoday.com/releases/274424.php?tw.
#Post#: 235--------------------------------------------------
Re: Tysabri & JC virus infection
By: agate Date: March 30, 2014, 6:21 pm
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More on this study appeared in DailyRx News, March 29, 2014:
[quote]Increased JC virus infection seen in MS patients taking
natalizumab
Author: Sheryl Wood / Reviewed by: Robert Carlson, M.D Beth
Bolt, RPh
Natalizumab is often used to fight the symptoms and progression
of multiple sclerosis, but the drug comes with a significant
risk of a rare and potentially fatal viral infection.
Multiple sclerosis patients who take natalizumab (brand name
Tysabri) have about three times the rate of progressive
multifocal leukoencephalopathy (PML) — a rare and usually fatal
disease of the brain. While it is known that PML is caused by
the JC virus, it isn’t clear why more MS patients taking
natalizumab get PML.
A recent study found that the JC virus may live and grow in
certain cells of the immune system and that natalizumab may
enhance this process.
"Ask your doctor about your MS treatment options."
Elliot M. Frohman, MD, PhD from the Department of Neurology at
the University of Texas Medical Center in Dallas, TX led the
research team.
The study involved three groups of people. Twenty-six multiple
sclerosis (MS) patients had their blood drawn before starting
natalizumab and regularly over the next 10 monthly treatments.
Another group of 23 patients had their blood drawn once after
they had completed at least 24 treatments with natalizumab.
Blood was also collected for a third group of 18 people without
MS who served as the control group for the study.
The research team measured the amount of JC virus in the blood
of the study participants. They looked at different types of
white cells in the patients, called CD34 and CD19 cells, to see
which cells the virus was found in.
JC virus was found in either the CD34 or CD19 white cells of
people in all three groups. The virus was found in cells of 50
percent of the patients starting natalizumab treatment, 44
percent of the patients who had more than 24 treatments, and in
17 percent of the normal control group.
Results of the research showed that the percentages of CD34 and
CD19 cells were higher in the blood of MS patients treated with
natalizumab, compared to people in the healthy control group.
This increase started after three months of treatment.
The authors theorized that the JC virus might have lived in CD34
cells in the bone marrow and that natalizumab moved these cells
into the bloodstream. They also suggested that the cells
infected with JC virus might become CD19 cells where the virus
could then grow.
“Continued studies are needed to further investigate natalizumab
treatments as the mechanism of PML,” the authors concluded.
The research was published in the March issue of JAMA Neurology.
Funding for the study was provided by the National Institute of
Neurological and Communicative Diseases and the National
Institute of Allergy and Infectious Disease, as well as a grant
from the National Multiple Sclerosis Society.
Dr. Frohman disclosed receiving fees for speaking and consulting
from Biogen Idec, makers of natalizumab.[/quote]
The article can be seen here
HTML http://www.dailyrx.com/increased-jc-virus-infection-seen-ms-patients-taking-natalizumab.
#Post#: 242--------------------------------------------------
Re: Tysabri & JC virus infection
By: agate Date: April 6, 2014, 4:32 pm
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From HealthDay, March 25, 2014, this article, "New Clues to Link
between MS Drug Tysabri and Rare Brain Disease"
HTML http://www.philly.com/philly/health/topics/HealthDay686134_20140331_New_Clues_to_Link_Between_MS_Drug_Tysabri_and_Rare_Brain_Disease.html.
#Post#: 342--------------------------------------------------
Re: Tysabri & JC virus infection
By: agate Date: June 3, 2014, 2:54 pm
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An editorial in the Multiple Sclerosis Journal, June 2, 2014,
gives a very understandable summary of the situation with
respect to JC virus testing and PML. If this link
HTML http://msj.sagepub.com/content/20/7/771.full
doesn't work for
people, I hope someone will let me know.
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