Detection of light subunit neurofilament and glial fibrillary acidic protein in cerebrospinal fluid of Trypanosoma brucei gambiense-infected patients.

Abstract

Abstract. Light subunit neurofilament (NFL) and glial fibrillary acidic protein (GFAP) concentrations were determined in cerebrospinal fluid (CSF) of 34 patients with human African trypanosomiasis (HAT), five serologically positive but parasitologically unconfirmed individuals, and four healthy controls without evidence of HAT. In patients with second stage HAT (n ϭ 30), NFL levels were abnormally elevated in 10 cases and GFAP levels in five. The astrogliosis observed in HAT and experimental models of HAT is confirmed in our study by the presence of increased GFAP levels in the CSF. The abnormal NFL CSF levels reflect structural damage of nerve cells in 33 % of the second-stage patients studied. To our knowledge, this is the first time neuronal damage in HAT patients is demonstrated by using biochemical markers of brain damage in the CSF.Human African trypanosomiasis (HAT) or sleeping sickness is a tropical disease caused by Trypanosoma brucei gambiense. Two consecutive disease stages can be discerned: 1 the first, a hemolymphatic phase, is followed by a second, meningoencephalitic phase, which is associated with the spread of trypanosomes into the central nervous system (CNS). The meningoencephalitis observed in African trypanosomiasis is characterized by parasite invasion of the meninges and choroid plexus, infiltration of the leptomeninges and perivascular areas by IgM producing plasma cells, Mott cells, and T helper/inducer cells, diffuse microglial hyperplasia, astrogliosis in the white matter, and demyelination of neurons. 2-6 A correct stage determination is indispensable since it is directly related to the choice of an optimal treatment with minimal risk for the patient. This is currently carried out by examining the cerebrospinal fluid (CSF) for cell number, protein concentration, and presence of trypanosomes.Other CSF parameters associated with second-stage HAT, such as the occurrence of IgM, 7,8 trypanosome-specific antibodies, [8][9][10] and autoantibodies against CNS components such as myelin, 11 galactocerebroside, 12,13 and the 200-kD and 160-kD neurofilament proteins, 14 have been described. These autoantibodies may be induced by cerebrospecific antigens leaking from injured nervous tissue, or otherwise may be actively involved in the pathogenesis of the nervous system damage in HAT by initiating or maintaining demyelination and nerve cell injury. 2,15,16 The glial fibrillary acidic protein (GFAP) is a major structural protein of astrocytes. It composes the glial intermediate filament, 17,18 which forms the morphologic basis of astrogliosis. 19 Immunohistochemical studies of GFAP in experimental and in vitro models of HAT show extensive astrogliosis accompanied by production of prostaglandin, interleukin-1 (IL-1), IL-6, macrophage inflammatory protein-1, tumor necrosis factor-␣, and interferon-␥, which contribute to CNS pathology. 6,[20][21][22][23][24][25] The observed astrocyte activation and associated cytokine production may be a key element in CNS inflammatory processes.The neurofilament is ...

Biological data and clinical symptoms as predictors of astrogliosis and neurodegeneration in patients with second-stage Trypanosoma brucei gambiense sleeping sickness.

“…11 Compared with the former study, 11 higher concentrations of GFAp and NFL in the CSF of patients with second-stage sleeping sickness and a higher proportion of patients with abnormal GFAp and NFL were observed. As shown in the current study, this can be explained by higher CSF cell numbers, higher CSF protein concentrations, and a higher number of patients with trypanosomes in the CSF within this study compared with the former study.…”

“…As shown in the current study, this can be explained by higher CSF cell numbers, higher CSF protein concentrations, and a higher number of patients with trypanosomes in the CSF within this study compared with the former study. 11 We found that increased cell number and protein concentration in CSF were associated with abnormal GFAp levels in a higher proportion of patients and were thus predictive for astrogliosis. An increased protein concentration could be the consequence of impairment of the blood-brain barrier, possibly caused by cytokine release from activated astrocytes or microglia.…”

“…The GFAp and NFL concentrations in CSF were measured by sandwich enzyme-linked immunosorbent assay. 10,11,27 Briefly, microtiter plates were coated with chicken anti-GFAp or anti-NFL immunoglobulin (Ig) G and reference GFAp or NFL, and duplicate samples of CSF were added; wells were incubated with rabbit anti-GFAp or anti-NFL IgG. Peroxidase-conjugated donkey anti-rabbit IgG (Amersham, Buckinghamshire, UK) was added, and plates were developed with o-phenylenediamine and perhydrol.…”

“…9,10 Abnormal concentrations of both GFAp and NFL in the CSF of patients with second-stage T. b. gambiense have been reported. 11 Gliosis, neuronal degeneration, or both might explain the clinical symptoms frequently observed in secondstage human African trypanosomiasis, including tremor, fasciculation of the muscles, choreiform, athetoid or oscillatory movements, and increased tonicity or muscular rigidity. 7,[12][13][14][15] A correlation between GFAp and NFL concentrations in CSF and clinical symptoms has been reported for several neurological diseases, including neuroborreliosis, normal pressure hydrocephalus, and multiple sclerosis.…”

Human African Trypanosomiasis

“…106 Antibodies against neurofi laments, galactocerebrosides, neurofi laments, and glial fi brillary acidic proteins are also promising CSF markers of second-stage disease. [107][108][109] The diagnostic approach for T b rhodesiense disease diff ers from that for T b gambiense in several ways. First, there is no serological screening test for T b rhodesiense.…”