New Lyme Test- Article dated March 2, 2001

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From Healthscout.com

New Test for Lyme Disease in the Works

Could reduce volume of incorrect results

By Nicolle Charbonneau

HealthScout Reporter

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FRIDAY, March 2 (HealthScout) -- A Philadelphia researcher believes he's

developed a more accurate test for Lyme disease.

The test looks for evidence of a substance produced by the organism that causes

the disease, rather than antibodies produced in response to the infection.

This should reduce the number of incorrect test results, says Brunner, a

rheumatology researcher at Children's Hospital in Philadelphia.

But the validity of the new test is questionable, says another Lyme disease

expert, because it has not been tested on enough people. Brunner's latest report

on the method, just published, was based on results from one person. But, he

says, an earlier study he co-wrote reports that the test detected Lyme disease

in more than 20 people with various stages of the disease.

Lyme disease is an infection caused by bacteria that's transmitted by the bite

of certain types of ticks. Early signs include flu-like symptoms, headache,

stiff neck, fever, muscle aches and fatigue. Usually, but not always, people

also develop a bull's-eye-shaped rash.

The disease can be treated with antibiotics, but if not detected and treated

early enough, it can progress to more serious problems with joint, nerve or

heart tissue.

Current blood tests for Lyme disease are insufficient, contends Brunner.

" The typical test [looks] for the antibody, " he says. " The antibody is made in

the body in response to the antigen, which is the invading organism. "

However, he says, these tests produce false positives by reacting to similar

organisms such as syphilis or Helicobactor pylori, or they produce false

negatives by failing to pick up signs of the antibody.

When a rash is present, diagnosis is usually simple. Without the rash, the

disease is difficult to diagnose because it has many vague symptoms. However,

Brunner says, as many as 40 percent of the people who contract Lyme disease do

not develop a rash.

Skin biopsies, while more accurate, generally are used only as research tools,

plus they're invasive and available in only a few medical centers, he says.

Brunner's test takes a blood sample and splits up immune complexes that may be

hiding the antigen.

" What my test does is capture the immune complex, break it about and prove that

the antigen or the protein from the Lyme organism is present, " Brunner says. The

antigen, known as OspA (for outer surface protein A), is the same one that's

present in the Lyme disease vaccine.

The person described in the latest study had tested negative on all other Lyme

disease tests, excluding the definitive skin biopsy test. But when Brunner used

his OspA-sensitive test, he says, the person tested positive.

" That's definitive proof that the patient was infected with Lyme disease,

whereas the other [antibody] tests were negative, " he says.

" It also tells whether you have active disease, " Brunner says. " If you've had

Lyme disease and were cured, antibodies can hang around, sometimes for years. If

that's the case, these antibodies would show up as positive on [the current]

Lyme test. My test would tell that the person now currently has active disease

because immune complexes are synonymous with an [active infection]. " A report on

the new test appears in the March issue of the Journal of Immunological Methods.

Brunner says his test would allow doctors to " catch [Lyme disease] early, when

you can treat it, " and it would indicate whether treatment worked. " When this

test becomes negative, the patient is actually cured, " he says.

But Dr. Eugene Shapiro, a professor of pediatrics, epidemiology and

investigative medicine at Yale University, and a Lyme disease expert in his own

right, has reservations about drawing such conclusions from Brunner's study.

" Clearly, before you can assess the validity of the test, you have to test it on

a considerably larger number of patients with different manifestations of

disease, " Shapiro says.

He also questions how many people actually would need the test, saying most

people develop the telltale rash.

" If you have the rash, the test is superfluous because the rash by itself is

diagnostic of Lyme disease, " Shapiro says. " There may be people who are not

familiar with the rash, or there may be rashes that are a little atypical.

Conceivably this might have some value in that setting, but only if it turned

out to be 100 percent sensitive. "

What To Do

For information about Lyme disease, check out the Lyme Disease Foundation or the

Centers for Disease Control and Prevention Web sites, or visit this public

information site funded by Pfizer, a pharmaceutical company.

Or, you might want to read previous HealthScout articles on Lyme disease.