Detection of viral antigen, IgM and IgG antibodies in cerebrospinal fluid of Chikungunya patients with neurological complications

Abstract

Background: During Chikungunya virus (CHIKV) epidemic in Nagpur, India, we identified some suspected Chikungunya patients with neurological complications. Early and cost-effective diagnosis of these patients remains problematic despite many new advanced diagnostic methods. A reliable diagnostic test, which could be performed in any standard pathology laboratory, would help to obtain definitive early diagnosis of CHIKV patients with neurological complications. In our laboratory, in-house ELISA protocol for viral antigen, immunoglobulin M (IgM) and IgG detection has been developed and assessed for the diagnosis of CHIKV patients with neurological complications.

Method: Cerebrospinal fluid samples of forty-six patients who developed neurological symptoms within two months of CHIKV infections along with control subjects were included in the study and were analyzed for the presence of antigens and of IgM and IgG using an ELISA protocol.

Results: The ELISA method for antigen detection yielded 80% sensitivity and 87% specificity for the diagnosis of CHIKV patients with neurological complications. The sensitivity for detection of IgM 48% or IgG 63% was significantly lower than the antigen assay (80%).

Conclusion: The detection of viral antigen in CSF of CHIKV patients with neurological complications by ELISA method gave a more reliable diagnosis than antibodies detection that can be used to develop an immunodiagnostic assay with increased sensitivity and specificity.

Figure 1

Mean absorbance values of ELISA assays for a) CHIKV viral antigen, b) CHIKV IgM, c) CHIKV IgG in CSF from patients with confirmed (n = 9) and suspected CHIKV (n = 37) with neurological complications and patients from non-CHIKV group (n = 15). Data are means +/- SD. * P < 0.05, ** P < 0.01 relative to control non-CHIKV subjects.