Aim -Diagnosis of acute hepatitis A virus (HAV) infection is classically based on the detection of HAV-IgM. Nevertheless, HAV-IgM can be positive for patients with polyclonal stimulation of their immune system (i.e. i...Aim -Diagnosis of acute hepatitis A virus (HAV) infection is classically based on the detection of HAV-IgM. Nevertheless, HAV-IgM can be positive for patients with polyclonal stimulation of their immune system (i.e. immune reactivation). To improve the diagnostic yield, an avidity test for HAV-IgG antibodies was developed and tested. Methods -Avidity tests were performed in 128 sera: 11 selected samples from patients with past infection, 15 acute hepatitis A, 10 vaccinated subjects and 4 patients with immune reactivation as well as 84 HAV IgM positive unselected sera, provided by routine laboratories. Results -Patients with past infection had avidities over 70%, whereas avidities in patients with acute hepatitis A were below 50%during the first month following the onset of symptoms. As expected, patients with immune reactivation had avidities over 70%consistent with past infection. The results obtained for the 84 unselected sera allowed reconsidering the diagnosis of acute hepatitis A for nearly a third of patients. Conclusion -This test could improve the diagnosis of acute hepatitis A infection, particularly in elderly patients.展开更多
文摘Aim -Diagnosis of acute hepatitis A virus (HAV) infection is classically based on the detection of HAV-IgM. Nevertheless, HAV-IgM can be positive for patients with polyclonal stimulation of their immune system (i.e. immune reactivation). To improve the diagnostic yield, an avidity test for HAV-IgG antibodies was developed and tested. Methods -Avidity tests were performed in 128 sera: 11 selected samples from patients with past infection, 15 acute hepatitis A, 10 vaccinated subjects and 4 patients with immune reactivation as well as 84 HAV IgM positive unselected sera, provided by routine laboratories. Results -Patients with past infection had avidities over 70%, whereas avidities in patients with acute hepatitis A were below 50%during the first month following the onset of symptoms. As expected, patients with immune reactivation had avidities over 70%consistent with past infection. The results obtained for the 84 unselected sera allowed reconsidering the diagnosis of acute hepatitis A for nearly a third of patients. Conclusion -This test could improve the diagnosis of acute hepatitis A infection, particularly in elderly patients.
