You might be wondering why you need to know the difference between immune responses. Well.....due to the difference in the two antibodies, four separate tests are available to test for their presence. Therefore, a physician must specify whether or not a patient should have an IgM or IgG Western Blot, or an IgM or IgG ELISA test.
I'd say at least 80% of the people who I have talked to had no idea which of the four tests they were given to test them for Lyme Disease or another tick-borne infection. Needless to say, its essential to know which test was given – it can help in estimating the time of infection (Lyme vs. Chronic Lyme) or can explain a false negative.
"Lyme is an enigma. While the debate rages over proper diagnostic and treatment procedures, patients get sicker and some even die." - Pat Smith, LDA, NY Assembly Hearing Nov, 2001
"Because the symptoms can be so varied and are often so vague, borreliosis is typically not even considered for testing or treatment." - Charles Crist, MD
Immune Responses Explained
IgM - is a sign of a recently contracted infection.
The first antibody our body makes in response to a foreign invader is usually immunoglobulin type M (IgM). This large antibody takes 2-4 weeks to be made in quantities large enough to be detected. It is at its peak of production four weeks after exposure to an antigen or in this case Lyme Spirochetes. The IgM antibody only stays in circulation for about three months.
IgM is 6x larger than the IgG antibody. Due to its size, this immunoglobulin is not believed to cross the placenta. Since it is fairly difficult for it to enter the fetus from the mother, any newborn that starts to make IgM antibodies against Lyme disease should be considered actively infected, however, a fetus exposed to Lyme Spirochetes early in the pregnancy may never make an antibody response to the Lyme bacteria because the baby's immune system doesn't recognize it as foreign. This means that doctors need to take a closer look at Lyme when babies are born with associated symptoms with no known origin (we'll discuss signs in babies and children in another post).
IgG - is a sign of an active infection, a past exposure to or past infection by the organism.
The second antibody we make after the IgM is the IgG antibody. This antibody takes 4-8 weeks to form and can be non-detectable after 4-6 months; peaking at about six weeks. This antibody crosses the placenta, so an infected mother can pass this antibody to her unborn child.
This antibody attacks viruses, bacteria, yeast, toxins, and transplants.
Many insurance company refuse to pay for more than one test. For example, the Western Blot IgG and the Western Blot IgM are completely different. The people approving and denying insurance claims lack education about Lyme and the bodies immune response so they consider the tests the same and deny claims for reimbursement on more than one test. It's like saying you can only test for one type of cancer – so choose wisely!
How much longer will we accept the lack of education about Lyme Disease and its impacts on the lives of people around us? People are having to spend thousands to tens of thousands of dollars out of pocket because their insurance company won't reimburse for Lyme testing or treatment regimes past 3 weeks! Write to your local congressmen, insurance companies and support Lyme education and research!