Seroprevalence and isotype immune response of IgG antibodies against human herpes virus 6 in HIV infected children

C. ACUIPIL, D. BUSTOS, S. CARRICART, P. BIGANZOLLI, L. MARTÍNEZ PERALTA, J. PAVAN.

Toronto, Canada.

Congreso; XVI International Conference on AIDS.; 2006

International Aids Society

Introduction: Human herpes virus 6 (HHV-6) is widely distributed lymphotropic virus. Following primoinfection, HHV-6 persists as a latent infection and it may reactivate, specially in immunocompromised hosts. To distinguish between those two stages the specific isotype patterns of IgG response has been proposed. A pattern of latency (IgG 1) and a pattern of reactivation (IgG1 & IgG4) were previously described; the latter in bone marrow transplant patients and in individuals with measles primoinfection. The aim of this work was to analyze seroprevalence and isotype patterns of IgG antibodies in children under 2 years of age infected with HIV.Methods: A total of 29 plasma samples of children infected with HIV diagnosed according to CDC criteria. Informed consent was obtained from the parents. 13 children belonged to stage B, 13 to C and 3 to A. Samples were tested by indirect immunofluorescence assay for IgG antibodies using the cell line Molt-3 infected with HHV-6 variant B, strain Z29. For isotype test, the reaction was stained using FITC conjugates mouse monoclonal antibodies against human isotypes. Mean geometric title (MGT) of the antibodies was calculated. Results: A seroprevalence of 89.7% for HHV-6 was detected, whereas in uninfected children seroprevalence is 63.5% (p< 0,005). In the samples from infected children MGT was 159 whereas in uninfected children a MGT of 57 was previously reported. An isotype response of IgG1 was observed 92 % of the samples, while IgG4 was uniformly negative.This pattern is similar to the one found in uninfected children. Conclusion: Seroprevalence as well as IgG titers for HHV-6 were significantly higher in HIV infected than in uninfected children. However, no reactivation pattern for HHV-6 was found, as described in other immunodepression conditions.