Kevin J. Black, M.D., one of the staff physicians at the Washington University Movement Disorders Clinic, is on the TSA's Physician Referral List. Some of you know him from our support group meetings. Here he answers some questions from our readers for general information. Since each person is different, you will want to contact your personal physician for specific medical advice.

A blood test for TS?
   The March, 1997, issue of the American Journal of Psychiatry reported a fascinating
research study involving TS.
    Here's the background. The story starts in 1976, with some researchers who were
studying a condition called Sydenham's chorea (which is basically rheumatic fever of the
brain). They found that these patients had antibodies in their blood that attacked brain tissue
instead of germs. This is probably because there is a protein on streptococci (the germs that
cause strep throat) which looks like parts of the brain to some of the body's infection-fighting
cells (called B cells). Sydenham's chorea is caused by an unusual reaction to strep. Later this
group found that people with high levels of a certain kind of B cell (called D8/17 positive
cells) were more likely to have rheumatic fever.
    Several years ago, the story got interesting for TS and OCD. A group of physicians at
the NIH and Brown University saw some children who had an untreated strep throat, got
Sydenham's, and at the same time developed new obsessions, compulsions, or tics. The
symptoms were sometimes mild and sometimes severe, but almost always faded away when
the Sydenham's symptoms improved. This was fascinating because, like tics, Sydenham's
chorea is a movement disorder that affects the parts of the brain (the basal ganglia) which are
implicated in tic disorders. These researchers tested the blood of some of these children and
found the same anti-brain antibodies that had been reported years before in Sydenham's. They
went on to look for these antibodies in children who had TS or OCD but not Sydenham's,
and they found the bad antibodies in many of these children, as well. This discovery led to
the idea that in some cases of TS or OCD, either (1) genetic factors may make the child
likely to have an unusual reaction to strep and also get TS/OCD, or else (2) untreated strep
infections may actually be the cause of TS or OCD in some patients who don't have it in the
family.
    The March research report tries to put together these two lines of research. At the
University of Florida, the department of psychiatry runs a clinic for OCD and TS. They
teamed up with two of the authors of the 1976 study to find out if the D8/17 positive B cells
had anything to do with OCD or TS. Investigators drew blood from 31 children with OCD,
TS, or both, and from 21 normal children in the community. Using a test which makes the
D8/17 positive B cells light up in the microscope, the researchers carefully counted 500 B
cells in each child and kept track of what percentage of these B cells were D8/17 positive.
Every one of the patients had more D8/17 positive cells than any of the controls.
Compared to a "normal cutoff" for the test from bigger groups of controls, 74% of the
children with TS or OCD were abnormal on this test, versus none of the comparison children.
This result looks real, although another group needs to verify the same results in
different patients to be sure.
    What's the point for a family with TS? This report is very exciting as a way of trying
to figure out what parts of the brain may be involved in TS. It is also very exciting as a
possible additional tool to help figure out what gene(s) may cause TS when it runs in
families. Finally, this research may give clues as to how to treat TS in certain unusual cases.
The group at the NIH has treated a few children whose tics, obsessions or compulsions start
"bang" very suddenly after an untreated strep throat. In these experimental studies they have
used penicillin or powerful immune-blocking treatments. In some of these unusual cases they
have seen good results, while in other subjects there has been little response.
    HOWEVER, what this means today to the average person with TS is not at all clear.
We don't know how good the blood test is until bigger groups of patients and controls are
studied, and at present there's absolutely no point in doing it on someone with TS or OCD.
Regarding treatment, it is not clear how useful or safe these treatments are for typical TS. At
this stage both the D8/17 blood test and these treatments must be considered purely
experimental.
    I know many of you want to fight back and find ways to better understand and treat
TS, and would like to volunteer. I will keep an ear to the ground and if I hear of good studies
relating to the D8/17 finding, I will pass the news on to MOTSA.
 

Kevin J. Black, M.D.