Antibody and B-cell responses may control circulating lipopolysaccharide in patients with HIV infection.

Objectives: To examine the relationship between plasma markers of microbial translocation and antibodies to lipopolysaccharide (LPS) and circulating memory B cells in patients with HIV infection.

Design: Cross-sectional study in antiretroviral therapy (ART)-naive (n = 23) and ART-treated (n = 27) HIV patients.

Methods: Antibodies to LPS and immunoglobulins, assayed in stored serum, and matched memory B-cell counts were correlated with levels of LPS and bacterial 16S ribosome DNA (16S rDNA), assayed in stored plasma.

Results: In ART-naive patients, plasma LPS levels correlated inversely with serum levels of IgG and IgA antibodies to LPS (P = 0.03 and 0.006, respectively), serum levels of IgA anti-LPS correlated with total IgA (P < 0.0001) and levels of IgG anti-LPS correlated with IgM(+) memory B-cell counts (P = 0.025). In ART-treated patients, plasma LPS levels were not related to levels of LPS antibodies, but were related to CD4(+) T-cell and switched memory B-cell counts. There were no correlations with plasma levels of 16S rDNA.

Conclusion: Plasma LPS levels were associated with antibody and possibly B-cell responses to LPS in ART-naive HIV patients, whereas they were associated with the degree of immune reconstitution in ART-treated patients.