One of the biggest challenges individuals with Lyme disease face is getting a correct, timely diagnosis
of their illness. The problem is the diagnostic tests that are currently available
, along with the current standard testing protocol, are a little outdated.
To discuss the pros and cons of the current diagnostic tests available for Lyme disease, members from academia, industry, and public health agencies—including some from the Centers for Disease Control and Prevention (CDC) and the US Food and Drug Administration (FDA)—convened at a Cold Spring Harbor Laboratory Banbury conference. The meeting was so fruitful that they decided to develop an article on the discussions, which was published today in the journal Clinical Infectious Diseases
“Currently the standard for laboratory diagnosis of Lyme disease is primarily based on the demonstration of antibodies against Borrelia burgdorferi
), the causative bacteria,” senior author Steven Schutzer, MD, a physician-scientist at Rutgers New Jersey Medical School told Contagion®
in an interview. “The testing paradigm, a 2-tiered protocol, consists of a sensitive first test, usually an enzyme immunoassay (EIA) that, if positive or borderline, is followed by a second assay, a Western immunoblot to increase specificity.”
Although this approach has become standard when it comes to Lyme disease diagnosis, it is not without its drawbacks; this is not surprising, as the paradigm was established in 1994. “Over ensuing years various shortcomings became apparent as new information was discovered,” Dr. Schutzer explained. “It was already known that it is insensitive in early weeks of the infection, and the interpretation of the Western blot has proven to be confusing to many doctors (blots are most often visually read by a person, rather than by a machine).”
This confusion is because when the Western blot criteria were formulated, “it was not known that some key proteins of the Lyme agent were only produced during an actual infection and these proteins were left out of the criteria,” Dr. Schutzer noted. The other problem is that there are some proteins that had been included in the criteria that are similar to proteins found in other bacteria. “These ‘cross-reactive’ proteins can bind antibodies produced against infections other than Lyme disease,” Dr. Schutzer explained. These issues with sensitivity and specificity have made interpretation of results challenging.
Luckily, a new generation of antibody tests has emerged, according to the authors of the article. One is a single multiplex assay with synthetic targets and another is a combination of EIAs. The next-generation EIAs, when compared with the commonly used EIAs that are prepared from whole-cell sonicates (WCS) of cultured B. burgdorferi
bacteria (WCS EIA), are more specific, and, as such, it has been suggested that they be used without a supplemental second-tier assay. Two large studies have been conducted to compare the specificity of next-generation EIA tests with the current 2-tiered testing paradigm (using WCS EIA followed by Western blot).
An approach to serologic testing suggested performing 2 EIAs sequentially in a 2-step process or simultaneously without a Western blot. The paper authors write that many investigators have examined the use of a “2-EIA” testing protocol—using the WCS EIA and the C6 EIA in a 2-tiered testing paradigm. “When these 2 tests are applied in 2-tiered testing, specificity is greater than that of either test alone and is equal to the specificity of standard 2-tiered testing with EIA and immunoblotting,” the authors write. Furthermore, research has shown that this approach can be more sensitive than the standard 2-tiered testing commonly used today.
The 2-EIA protocol shows several benefits over the standard testing protocol, according to the article:
- Results are straightforward (the patient is seropositive or seronegative) and objectively obtained via an instrument system.
- It may be more cost-effective than protocols that call for immunoblotting.
- The methodology is more easily accessible to most clinical laboratories, which can decrease turnaround time to yield results.
The other testing platform consists of a single multiplex test “designed to provide information about antibody responses to multiple Borrelia
antigens, including bead-based assays or microchip configurations,” the authors write. “This approach offers the prospect of a single-tier assay in the near future and lends itself to adaptations as new data are discovered.”
The authors reference a study that supports the single multiplex concept which used epitope mapping of key B. burgdorferi
antigen targets from both in vivo
and in vitro
expressed antigens. They noted that “peptides containing specific epitopes, with or without recombinant antigens, are uniquely suited as antigen targets in multiplex platforms.” As an example, one bead-based assay included 10 separate antigens, some of which comprised epitopes that were more specific than those found in the Western blots using the 1994 Dearborn criteria. In that evaluation, the antigen panel was more sensitive in early Lyme disease than the standard 2-tiered algorithm while maintaining high specificity.
Although advances made in testing approaches are helpful, Dr. Schutzer stressed that laboratory tests are adjunctive tools that should be used in tandem with patient evaluation by health care providers.
“The earlier you can make a diagnosis, the earlier you can give rational treatment, and that’s your best chance for curing and simultaneously preventing long-term neurological, cardiac, or joint problems,” Dr. Schutzer stressed.
The article, “Advances in serodiagnostic testing for Lyme disease are at hand,” was published online early on December 7, 2017, in Clinical Infectious Diseases
. DOI: 10.1093/cid/cix943
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