Western Blot - Lyme Disease Western Blot Test

The Western Blot essentially makes a map of the different antibodies the immune system produces to the bacteria. The map separates the antibodies by the weight of their respective antigens and are reported in units called kilo daltons or kDa. For example, a Western Blot may report bands at 22, 23, 25, 31, 34, 39, and 41 kDa. Each of these bands represents an antibody response to a specific protein found on the spirochete. The 41 band indicates an antibody to the flagella 41 kDa protein and is nonspecific. The 31 kDa band represents the OSPA protein and is specific for just a few species of Borrelia, as is the 34 band OSPB, and 23 kDa OSPC.

In 1994, the Association of State and Territorial Public Health Laboratory Directors, under a CDC grant, decided that there should be consistency between labs reporting Lyme disease Western Blots, and that a specific reporting criteria should be established. The consensus committe, chaired by Dr. Michael Osterholm, Ph.D., MN, set nationwide standards for Western Blot reporting. This sounds good, but one could argue they made a bad situation worse. Prior to the hearing, virtually every lab had accepted bands 22, 23, 25, 31, and 34 kDa as specific and significant, and reported them as positive for exposure to Borrelia burgdorferi. Not only are these bands specific for Borrelia species, but they represent all of the major outer surface proteins being used to develop the Lyme vaccines. The committee, without any clear reasoning, disqualified those bands as even being reportable.

After the consensus meeting, those bands were no longer acceptable. The result was that what had been a fair-to-good test for detecting Lyme disease had now become poor, arguably useless. Many scientists have questioned these new reporting criteria, and several wrote letters of protest to both the committee and to laboratory journals. Many labs stopped reporting the actual bands and instead, simply reported the test as positive or negative, thus preventing any further interpretations. (90)

How badly did the Lab Directors bootstrap this test? The following is an analysis of the new guidelines presented as an abstract and lecture at the 1995 Rheumatology Conference in Texas, chaired by Dr. Alan Steere, MD. (1995 Rheumatology Symposia Abstract #1254, Dr. Paul Fawcett, et al.)

This was a study designed to test the recently proposed changes to Western Blot interpretation by the Second National Conference on Serological Testing for Lyme Disease, sponsored by the CDC. The committee proposed limiting the bands that could be reported in a Western Blot for diagnosis of Lyme disease. Out of a possible 25 bands, 10 specific bands were selected as being reportable. An lgG Western Blot must have five or more of these bands: 18, 21,28, 30, 39, 41,,45, 58, 66 and 93 kDa. An lgM Western Blot must have two or more of the following three bands: 23, 39, 41.

Conspicuously absent are the most important bands, 22, 23, 25, 31, and 34, which include OSPA, OSP-B and OSP-C antigens - the three most widely accepted and recognized Bb antigens. These antigens were the antigens chosen for human vaccine trials. This abstract showed that, under the old criteria, all of 66 pediatric patients with a history of a tick bite and bull's-eye rash who were symptomatic were accepted as positive under the old Western Blot interpretation.

Under the newly proposed criteria, only 20 were now considered positive. (The number of false positives under both criteria was zero percent.) That means 46 children who were all symptomatic would probably be denied treatment! That's a success rate of only 31%.

*Note: A misconception about Western Blots is that they have as many false positives as false negatives. This is not true. False positives based on species specific bands are rare.

The conclusion of the researchers was: "the proposed Western Blot reporting criteria are grossly inadequate, because it excluded 69% of the infected children."