[Diagnostic efficacy of phosphorescent immunochips for serologic diagnostics of tick-borne encephalitis].

AIM: To assess sensitivity and specificity of phosphorescent immunochips developed by the authors on the basis of microplate phosphorescent assay (PHOSPHAN) for detection of IgM and IgG antibodies to tick-borne encephalitis virus (TBEV) in sera of patients and to compare results of PHOSPHAN assay with results obtained by lanthanide immunofluorescence assay (LIFA) and solid-phase enzyme immunoassay (SPEIA).

MATERIALS AND METHODS: Two hundred sixty one serum samples were tested, including 155 samples from 74 patients with clinical diagnosis of TBE confirmed by serologic identification of IgM antibodies to TBEV. Sera were collected in 2003 in Perm region from persons, which fell ill during seasonal increased activity of ticks-vectors of TBEV, as well as from healthy blood donors. Phosphorescent immunochip corresponds 96-well plate with 4 active microzones formed on the bottom of each well, which are able to detect specific IgM and IgG antibodies to TBEV. Immune reaction was visualized by conjugate of streptavidin with Pt-coproporphyrin. Intensity of fluorescence was measured by scanning the bottom of previously dried microwell with scanner IFI-02.

RESULTS: Comparable sensitivity and specificity of POSHPHAN assay, LIFA and SPEIA was demonstrated for detection of IgM and IgG antibodies to TBEV in samples. Immunoluminescence-based PHOSPHAN assay and LIFA were more sensitive for analysis of sera with low titer of specific IgM antibodies.

CONCLUSION: PHOSPHAN assay could be used for early serologic diagnostics of TBE as well as for assessment of antibody level for control of efficacy of treatment in patients with prolonged illness or level of protective immunity in vaccinees.