Background The neurological injury in rheumatoid arthritis (RA) is one of the most common organ lesions, but its clinical statement is quite complicated because of absence of reliable signs, as well as frequent coexistence with other neurological conditions. Therefore, the new improved approaches for diagnosing of nervous system involvement are rather necessary, and immunological methods of detection are appeared more promising and more specific for RA than imaging. The most obvious candidate antigens for this purpose are the constituents of nervous tissue, such as myelin and its principal component, myelin basic protein (MBP).
Objectives Improvement of immunological detection of neurological involvement in RA by means of polyacrylamide magnetic beads with immobilized MBP.
Methods The research was carried out in agreement with the principles of the World Medical Association Declaration of Helsinki. The informed consent had been signed by all involved persons, another obligate requirement was age 18 years or more. The patients were from the rheumatologic wards in Volgograd Municipal Hospital No. 25 and Volzhsky Municipal Hospital No. 1. Diagnosis of RA was established by ACR-EULAR criteria (2010), RA activity was evaluated using DAS28. Serum anti-MBP antibodies were measured by ELISA, with MBP immobilized on polyacrylamide magnetic beads as an antigen. The antibody concentrations were expressed as optical density units (ODU) and were considered positive if the cutoff value (M+2σ of the reference group, 0.050 ODU) was exceeded. The results were expressed as mean±σ, differences were considered significant when p<0.05. Pearson correlation coefficient (r) was also used.
Results 40 healthy persons (29 mans and 11 women), and 95 female patients with RA and the neurological signs, appeared during active phase of the disease, were recruited for this study. Mean age of the healthy controls was 36±7 years, and for the RA group it was equal to 55±11 years. Mean RA duration was 4.2±2.9 years. 13 patients had low, 52 – moderate, and 8 – high disease activity. The most common types of neurological involvement were mononeuropathy (n=29), polyneuropathy (n=65), radiculopathy (n=80); cervicocranialgias (n=51), and trigeminal neuralgias (n=14). The symptoms of central nervous system damage (TIA, seizures, cerebellar ataxia, dysarthria) were found in 21 patients. In RA group, anti-MBP antibodies were detected in 37 (38.9%) cases, with mean concentration 0.141±0.027 ODU. The patients with different neurological signs had mean anti-MBP antibody concentration 0.198±0.050 ODU, the subgroup without any neurological signs had 0.120±0.024 ODU (p=0.022). There was positive correlation between anti-MBP concentration and DAS28 score (r=0.67, p=0.039).
Conclusions We found an association between neurological involvement in RA and elevation of anti-MBP antibody concentrations, as well as correlation between the latters and DAS28 score. These findings give us an opportunity to improve the diagnosis of minor neurological damage in RA and thus to make more precise adjustment of the treatment.
Disclosure of Interest None declared