RESUMO
Objective To develop an ELISA(Enzyme-Linked Immunosorbent Assay)diagnostic kit for early rapid detection of sarum anti-EV71 antibody and evaluate its clinical application value.Methods Recombinant protein VP1 of EV71 were prepared and purified as an immobilized antigen for establishment of an indirect ELISA for detection of serum anti-EV71 IgM and anti-EV71 IgG.Compared with RT-PCR.isolation of EV71 and micro-neutralizing assay.the clinical application value of anti-EV71 IgM and anti-EV71 ISG in the diagnosis of EV71 disease was evaluated.Results In comparison with RT-PCR.the sensitivity,specificity,positive predictive value and negative predictive value of anti-EV71 IgM antibody were 83%,85%,81%and 87%,respectively.The sensitivity,specificity,positive predictive value and negative predictive value of anti-EV71 IgG antibody were 72%,74%,68%and 77%.respectively.Compared with viral isolation assay.the sensitivity and specificity of anti-EV71 IgM antibody were 85%and 97%,respectively.The sensitivity and specificity of anti-EV71 IsG antibody were 75%and 77%,respectively.In addition.the titers of anti-EV71 IgG antibody were significantly correlated with the titers of neutralizing antibody to EV71 by linear regression analysis(r=0.72,P＜0.05).Finally,the serum titers of anti-IgG from patients with EV71 associated hand food and mouth disease at convalescent stage exhibited significantly higher than that of the same patients at acute stage(P＜0.01),but the titers of anti-IgM had no significant difference(P＞0.05).Conclusions With VP1 recombinant protein used as an immobilized antigen,an indirect ELISA diagnostic kit was successfully develooed for detection of serum anti-human EV71 IgM and anti-human EV71 IgG antibodies.