Lyme disease or not? How "false" antibodies can confuse the diagnosis

Dr Dubrovsky, an infectious disease specialist, talks about the results of an ongoing study conducted by his clinic.

It turns out that positive IgM antibodies in the complete absence of IgG antibodies are often found in people with autoimmune diseases (scleroderma, autoimmune thyroiditis, psoriasis, Bechterew's disease, multiple sclerosis, various autoimmune arthritis). But do such cases really have Lyme disease itself?

According to official guidelines, if a patient has only "M"-antibodies present, without IgG, the diagnosis of "borreliosis" is highly doubtful. In practice, this means that many patients with only "M" antibodies may be misdiagnosed and undergo multiple courses of treatment. In the end, people are disappointed: the antibodies don't go away, the condition doesn't improve, and the real cause of the symptoms may be quite different.

Dr Dubrovsky notes that the percentage of false positives is still noticeable. This is a signal for the manufacturers of test systems to improve the sensitivity and specificity of their analyses, and for doctors who should not rush to make diagnoses based only on "M" values.

An interesting case was that of a patient with myeloleukaemia: he was found to have not only an "M" but also a "G". He had been treated twice with the right antibiotics by experienced infectious disease specialists, but the antibodies had not disappeared for years. A more detailed comparison of analyses for different years revealed that the diagnosis of borreliosis itself was highly questionable. The question arose: whether the organism against the background of oncological process cannot cope with borrelia, or whether there is no pathogen at all, and the synthesis of antibodies occurs for other reasons (due to weakened immunity or autoimmune reaction).

Such situations once again confirm that one should not jump to conclusions if only "M"-antibodies are present. They may well turn out to be false positives.

Today, the "gold standard" for diagnosis remains G antibodies and, in difficult cases, a confirmatory immunoblot, which can determine whether even G antibodies are false positives. Research into this problem is ongoing and it is important to ensure that patients receive a correct diagnosis and do not waste time and energy on unnecessary treatment.