Increase in plasma viral load after oral cholera immunization of HIV-infected subjects.

Constant antigenic stimulation of the large immune cell population contained within gut-associated lymphoid tissue during HIV infection may contribute to patients total viral load. The aim of this investigation was to evaluate the effect of a mucosal antigenic challenge on HIV replication. Design: Prospective clinical study. Twelve HIV-1-infected men (mean age 42.3 years) from the Casa de Apoio Santo Antonio Rio de Janeiro Brazil were immunized with combined whole cell--toxin B subunit oral cholera vaccine. Blood was collected on days 0 2 4 6 10 and 15 after immunization and plasma was tested for cholera toxin-specific antibody response (IgG and IgA) b2-microglobulin and plasma viral load. CD4 lymphocyte counts were performed within 1 week before immunization. Five HIV-infected nonimmunized individuals were studied as controls. There were no adverse effects following immunization and no deterioration in clinical outcome during 3 months of follow-up. A transient increase in viral load that ranged from twofold to 60-fold was observed in all cases and was statistically significant on days 2 6 and 10 (P = 0.017 P = 0.025 P = 0.021 respectively). There was no correlation with CD4 cell counts. None of the non-immunized subjects demonstrated the pattern of viraemia observed after immunization (P > 0.10 on all days). Our data indicate that mucosal immunization with oral cholera vaccine induces a transient increase in HIV viraemia regardless of clinical stage of infection and CD4 cell counts. These findings suggest that mucosal stimulation of HIV-infected patients enhances HIV replication. (authors)