Time to Throw Out Western Blots for Lyme Disease?

by lmatthews on May 8, 2013

tests for lyme diseaseThe current US Centers for Disease Control recommendations for Lyme disease testing involve a two-tiered process of ELISA and Western Blot. Such testing has come under fire for many years with mounting evidence of the lack of sensitivity and specificity of this testing but the CDC has maintained a firm stance and have not revised their guidelines.

Many patients convinced that they have Lyme disease have been unable to access medical treatment because of negative test results, meaning that insurers will not pay for treatment and many are left paying thousands to physicians, and occasionally quacks, who work outside of the medical mainstream guidelines. Now, however, another study has added weight to the argument against using Western Blots for Lyme disease, recommending that these ‘cumbersome immunoblots’ are thrown out.

A New Lyme Disease Testing Protocol?

This new research involved Allen Steere, the doctor who investigated the outbreak of Lyme disease that led to the naming of the infection. It is interesting that a study by a man considered to be part of the ‘old guard’ of Lyme disease thinking highlights the merits of a new approach to Lyme disease testing, using a newer-generation C6 peptide ELISA test. This test has actually been in use for dogs with Lyme disease for some time. This C6 test would be in addition to the traditional ELISA test for Lyme disease and would offer a way of testing that is already commercially available, meaning that the switch-over could begin right away.

European Lyme Disease Testing

This study, published in Clinical Infectious Diseases, was designed to tackle the issue of patients with Lyme disease who were infected whilst travelling in Europe, where the strains of the bacteria are a little different to those of the US. This can cause problems when immunoblots only test for antibodies to the local strain of Borrelia (the Lyme disease bacteria), B. burgdorferi sensu stricto. In Europe, several different strains of Lyme disease bacteria are present, including B. afzelii, B. garinii and B. bavariensis sp. nov. As such, tests designed for Lyme disease in Europe are more sensitive to a variety of Borrelial strains, whereas the US tests remain very narrow in their scope.

Reinfection with Different Lyme Disease Strains

Borrelia burgdorferi sensu lato have also been found to have a variety of mutations that may evade tests rather easily. Recent research has even noted that subsequent infection with different strains of the bacteria is actually the more likely cause of recurrent symptoms, instead of chronic Lyme disease and relapses.


Western Blots Usefulness for Lyme

Western Blots are also unhelpful in the very early stages of the disease, requiring a period of several weeks to pass after a tick bite in order for antibodies to have gained sufficient levels to show up on the test. Patients who have a poor immune system response to the infection may also have very low levels of antibodies and even show up as negative on this test, as can those for whom antibiotic treatment is working but where the treatment has not yet completely eradicated the infection.

What this Study Involved

The study that could help change the CDC guidelines on Lyme disease testing was carried out on 64 blood samples from patients infected in Slovenia, all in Ljubljana. These patients had varying stages of the disease and were compared against 100 healthy volunteers from New Zealand, where Lyme disease is not considered endemic and where the infection is virtually non-existent.

C6 ELISA More Sensitive than Current Tests

Results in this study revealed the the CDC’s conventional testing programme had an overall sensitivity of 52% and specificity of 100%. In contrast, the European tests were 81% sensitive and 99% specific. What’s more, the C6 ELISA test that is currently available in the US was actually 88% sensitive on its own and had 100% specificity. The researchers also looked at the use of both a standard ELISA test for Lyme disease followed by the newer C6 ELISA and found that it had an overall sensitivity of 84% and 100% specificity.

Will CDC Revise Lyme Disease Testing?

The authors of this study concluded that:

“European assays outperformed analogous U.S. assays in a conventional 2-tiered testing algorithm. However, a C6 ELISA used as a stand-alone test or in the second-tier of a 2-tiered algorithm performed comparably to conventional 2-tiered testing using European assays, and can be used for evaluation of any patient, regardless of travel history. “

Such evidence provides significant weight to calls for the current two-tier testing process for Lyme disease to be revised for the benefit of patients in the US, whether they have recently travelled abroad or not. It remains to be seen whether the Western Blot for Lyme disease will be thrown out any time soon or if the CDC requires yet more evidence of better tests being available before Lyme disease testing protocols change.

Reference

John A. Branda, Franc Strl, Klemen Strle, Nikhil Sikand, Mary Jane Ferraro, Allen C. Steere, Performance of United States Serologic Assays in the Diagnosis of Lyme Borreliosis Acquired in Europe, Clin Infect Dis. (2013) doi: 10.1093/cid/cit235.


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