IMMUNOLOGICAL ASPECTS OF NEUROSYPHILIS

Abstract

Reduced incidence of syphilis was reported in Russia over last years, along with increased prevalence of neurosyphilis. The issues of the mechanisms of the damage of nervous system and the immune response to syphilis are actual. Origin of syphilis antibodies from cerebrospinal fluid of patients with neurosyphilis is considered. The role of intrathecal immunoglobulin production and dysfunction of blood-brain barrier in patients infected with syphilis is of special importance. The aim of the research was to analyze the immunological aspects of neurosyphilis. Polymorphonuclear leukocytes have been shown to play an important role in infection with Treponema pallidium during clearance of the pathogenes. Potential virulence factors of Treponema pallidium have been discovered. It has been found that cell-mediated immune response is very important for defense against Treponema pallidium, while the key importance in bacterial clearance is put on Th1. Evidence has shown that the level of cytokines which are secreted by Th1 (IL-2, interferon gamma and tumor necrosis factor) and Th2 (IL-6 and IL-10) — lymphocytes, correlates with syphilis progression. The role of IL-10 in immune response regulation in patients infected with syphilis has been examined: this cytokine can inhibit the activity of immunocompetent cells. Some data has been produced concerning intrathecal production of immunoglobulins in neurosyphilis patients’ cerebrospinal fluid. The research of immunological parameters and composition of liquor in the patients with syphilis has revealed, that lymphocytes of peripheral blood are sensitized to antigens of the brain. It indicates the violation of permeability of patients’ blood-brain barrier. Nervous system becomes involved into the pathological process during the first weeks or months after syphilis infection. Cerebrospinal fluid changes can be detected at seronegative stage of the primary infection. The most expressed changes were found in the cerebrospinal fluid of patients with secondary recurrent syphilis It was established that high titers of treponemas specific antibodies in the cerebrospinal fluid of patients are the consequence of inflammation of the central nervous system. According to our data, cytosis and protein levels in the cerebrospinal fluid of patients with meningovascular syphilis were significantly higher than these in individuals with a history of syphilis and negative serological results in the research of the cerebrospinal fluid. Thus, advances in the study of the immunological aspects of syphilis promote early diagnosis of neurosyphilis and development of vaccines against syphilis.