Lyme disease is caused by infection with Borrelia burgdorferi bacteria and is transmitted to humans by tick bites. Infections occur primarily in areas where B. burgdorferi bacteria, infected animal reservoirs, and the tick vectors for transmission co-exist in proximity to suburban human populations. New infections are most common in the summer when the nymphal ticks are seeking blood meals [2].
Lyme disease typically progresses in three stages [2]. Early Localized Lyme disease (Stage I), in the days and weeks immediately following the infection with B. burgdorferi, is characterized by mild flu-like symptoms (headache, fever, swollen lymph nodes), usually accompanied by striking dermatological manifestations, famously, the “bull’s-eye” rash, erythema migrans (EM). EM is considered diagnostic for Lyme disease especially in endemic areas and the Infectious Disease Society of America (IDSA) recommends initiation of antibiotic therapy, typically a two-to-four week course of oral doxycycline, based on the presence of EM alone in such areas. Untreated B. burgdorferi infections often develop systemic manifestations that can lead to serious sequelae. Early Disseminated Lyme disease (Stage II) develops several weeks or months after the tick-bite and may be accompanied by the emergence of multiple EM lesions, severe flu-like symptoms, and pronounced articular, neurological or cardiac symptoms. Stage III, the Late Disseminated Stage, can present months or years after the initiating tick-bite with profound neurological sequelae and severe inflammation of major joints commonly known as Lyme Arthritis.
The incidence of Lyme disease is thought to be under-reported. The Center for Disease Control (CDC) reported 30,000 cases of Lyme disease in 2009, which was likely to be a substantial underestimate since in 2013, nearly 300,000 cases per year were cited [2, 3, 5]. There are many reasons such a serious and distinctive infection is under-reported. First, not every patient develops the signature EM rash [6, 7], but probably a far greater number simply do not see the rash or recognize its significance. Furthermore, symptoms of Lyme are nonspecific, e.g., vague, flu-like symptoms.
The CDC recommended two-tiered serology test is currently considered the “Gold Standard” for evidence-based diagnosis of Lyme disease [1, 8]. Patient sera are initially tested using an enzyme immunoassay (EIA) that measures the presence of antibodies that bind to a whole cell sonicate (WCS) of a lab strain of B. burgdorferi. Positive or equivocal serum samples are then tested with a Western blot immunoassay using a similar WCS. Samples are considered positive for Lyme disease if they contain antibodies that react with at least 5 of 10 characteristic bands [8]. Three fundamental limitations of this diagnostic testing process are widely recognized: i) low sensitivity in Stage I Early Localized Lyme disease, ii) inability to distinguish a new infection from prior infection(s), and (iii) inability to assess effectiveness of therapeutic interventions.
The low clinical diagnostic sensitivity in Stage I of Lyme disease is due to the slow appearance of anti-B. burgdorferi antibodies that can be detected in the blood, usually 4 – 6 weeks after the initiating tick bite. There is thus a multi-week indeterminate period where numerous studies have demonstrated frustratingly poor sensitivity for detecting anti-B. burgdorferi antibody and diagnosing Lyme disease [1, 9 – 14]. This poor diagnostic sensitivity of current methods among EM-positive Stage 1 Lyme patients, creates compromised situations for clinicians. Even skilled physicians can be confused by the appearance of the EM rash that can be heterogeneous in appearance [6]. Less experienced clinicians and those in areas where the incidence of Lyme disease is low tend to rely on lab tests for confirmation, possibly delaying early intervention. Thus, low sensitivity compels clinicians to initiate antibiotic therapy based on EM alone and provides poor diagnostic support for subjects who do not have EM or do not know they had a tick bite. Not only is current diagnostic testing of limited utility for rule-in diagnoses, its poor sensitivity limits its utility for rule-out diagnoses since bites from ticks transmitting pathogens other than B. burgdorferi may present with a look-alike EM rash [15]. Early in the infection, when clinicians can offer patients the greatest benefit, the modest sensitivity of current diagnostic tests leaves many patients untreated until more severe Stage II sequelae develop and therapy is less likely to be effective.
The inability to distinguish a new infection from prior exposure(s) and to assess the success of therapeutic interventions represents additional fundamental deficiencies of current Lyme diagnostic methods: serum antibody levels will remain high long after the pathogen has been cleared [1, 16 – 18]. Retesting to assess for cure is not recommended and “not justified and often leads to unnecessary repeat courses of antibiotics” [1]. Some experts recommend that in patients who are known to be seropositive, “it would be desirable to have another type of assay to judge whether new onset symptoms are actually due to active Lyme disease. These well-recognized limitations of the current two-stage serologic testing for Lyme disease” [4] are solved with MicroBplex’ technology.
HOW MICROBPLEX IS HELPING
MENSA is a defined cell culture medium containing the newly synthesized antibodies secreted by ASCs harvested from the blood of subjects suspected to be infected with B. burdorferi, the Lyme disease bacteria. We measure the newly synthesized ASC antibodies with a sensitive multiplexed Luminex™ immunoassay platform. The major advantages of MENSA include: i) the circulating blood ASC that make the newly synthesized MENSA antibodies appear in blood circulation a few days after infection, weeks earlier than detectable blood antibody, and provide earlier diagnosis than achievable with current Lyme diagnostic methods; ii) MENSA is completely free of pre-existing antibodies and permit new infection with B. burgdorferi to be distinguished from prior infection(s); and (iii) ASCs cease to be formed and disappear from blood circulation once the B. burgdorferi pathogen has been eliminated and the resulting absence of MENSA ASC antibody provides an indication of therapeutic effectiveness. The MicroBplex Lyme diagnostic therefore detects infection with B. burgdorferi earlier than any other Lyme diagnostic at a time when therapy can be most effective, and is the only diagnostic that discriminates a new active infective from a prior exposure to B. burgdorferi and provides definitive indication of elimination of the B. burgdorferi organism following therapy.