IgM quantification in the cerebrospinal fluid of sleeping sickness patients by a latex card agglutination test
Abstract:An increased IgM concentration in cerebrospinal fluid (CSF), occurring as a consequence of massive intrathecal IgM synthesis, is a marker of interest for diagnosis of the meningo-encephalitic stage in human African trypanosomiasis. However, in current practice, IgM in CSF is not determined because of the lack of a simple and robust test that is applicable in African rural regions where the disease prevails. We describe the development of a sensitive semiquantitative card agglutination test, LATEX/IgM, for IgM quantification in CSF. The test is simple and fast and the lyophilized reagent remains stable even at 45 °C. CSF end-titres obtained with LATEX/IgM parallel the IgM concentrations determined by nephelometry and enzyme-linked immunosorbent assay. Detection of intrathecal IgM synthesis is the most sensitive marker for CNS involvement in sleeping sickness. At a cut-off value of ≥ 8, the sensitivity and specificity of LATEX/IgM for intrathecal IgM synthesis are 89.4 and 92.7%. As a consequence, patients with LATEX/IgM end-titres ≥ 8 are likely to have intrathecal IgM synthesis, thus central nervous system involvement and therefore should be treated accordingly. Further studies should concentrate on the relationship between the LATEX/IgM end-titres, presence of intrathecal IgM synthesis and occurrence of treatment failures in patients treated with pentamidine.
Document Type: Research Article
Affiliations: 1: EPICENTRE, Paris, France, 2: International Medical Corps, Nairobi, Kenya, 3: Médecins Sans Frontières-Espagne, Haut Mbomou, République Centrafricaine, 4: Institut Pierre Richet, Bouaké, Côte d'Ivoire, 5: OCEAC Laboratoire d'Etude de la Chimiosensibilité des Trypanosomes, Yaoundé, Cameroun, 6: Projet de Recherches Cliniques sur la Trypanosomiase, Daloa, Côte d'Ivoire, 7: Bureau Central de la Trypanosomiase, Bwamanda, R.D. Congo, 8: Department of Parasitology, Institute of Tropical Medicine, Antwerpen, Belgium, 9: Department of Clinical Sciences, Institute of Tropical Medicine, Antwerpen, Belgium, 10: Merck Eurolab, Fontenay-sous-Bois, France
Publication date: August 1, 2002