2 Types of MS, Study Reveals
Blood Test Would Predict Success of Multiple Sclerosis Treatment
Two Routes to MS continued...
Why doesn't beta interferon always work for MS patients? A clue comes from a little known but equally devastating disease called neuromyelitis optica (NMO). In NMO, the immune system attacks nerve fibers, but it targets a protein different from myelin, says NMO researcher Michael R. Yeaman, PhD, vice chair of medical sciences at Harbor-UCLA Medical Center.
NMO researchers have shown that the CD4 cells behind NMO aren't Th1 cells, but another type called Th17. Might Th17 cells cause some cases of MS?
Yes, Steinman and colleagues found. First the researchers induced an MS like disease in mice using either autoimmune Th17 or autoimmune Th1 cells. Then they showed that beta interferon improved MS-like symptoms in mice with Th1-induced disease, but that the drug worsened MS symptoms in mice with Th17-induced disease.
Humans, too, appear to have different kinds of MS. Steinman and colleagues tested blood samples taken before treatment from 26 MS patients. Six of the 12 patients who did not respond to beta interferon had high levels of Th17 in their blood.
These patients with Th17 immune responses also had high levels of beta interferon in their blood -- before beta interferon treatment. That means one of two things:
- In patients with Th17-type MS, beta interferon doesn't help because beta interferon levels already are high.
- In patients with Th17-type MS, beta interferon doesn't fight inflammation -- it makes inflammation worse. In this case, just as in mice with Th17-induced disease, beta interferon would exacerbate MS.
New Hope for MS Patients
"We are very excited about this kind of discovery, because there are new therapy approaches that focus on Th17 immune pathways," Yeaman tells WebMD. "We don't know the answers yet, but we are starting to see the dots on the page -- and if we can connect the dots, perhaps a new treatment or cure can emerge."
People with MS are likely to see a benefit long before new treatments emerge. Blood tests already exist that can tell MS patients whether they have Th1 or Th17 disease. Those with Th17 disease can be spared having to undergo the side effects of beta interferon treatment, while those with Th1 disease can endure side effects knowing that the treatment is highly likely to work.