[Diagnosis of sleeping sickness stage: towards a new approach].

Diagnosis of the neurological disease stage in Trypanosoma brucei (T.b.) gambiense infection is essential to select an optimal chemotherapy. The actual parameters for stage determination, the cerebrospinal fluid (CSF) cell count, total protein concentration and trypanosome detection, are insufficiently specific and sensitive. In order to identify new parameters for stage determination, we studied the neuro-inflammatory immune response in the central nervous system, notably the intrathecal humoral immune response in sleeping sickness patients. The presence of intrathecal IgM synthesis was identified as an excellent marker of central nervous system involvement. However, intrathecal IgM detection cannot be performed under field conditions. As a consequence of the strong intrathecal IgM synthesis, extremely high concentrations of IgM are found in the CSF of sleeping sickness. We therefore developed a latex agglutination field test (LATEX/IgM) indicative for intrathecal IgM synthesis and CNS involvement in sleeping sickness. Based on our observations on the intrathecal immune response and with LATEX/IgM, we propose a new approach for stage determination in sleeping sickness.