Impact of Autologous Dendritic Cell Immunotherapy (Arcelis^™) on B Cell Subsets in HIV-1-Infected Subjects Receiving Antiretroviral Therapy

We demonstrated the enhancement of CD8-specific responses following the administration of an immune-based therapy consisting of dendritic cells (DC) electroporated with autologous amplified HIV-1 RNA and CD40 ligand (CD40 L) RNA manufactured by the Arcelis^™ process in HIV patients receiving antiretroviral therapy (ART). We conducted a sub study on circulating B cell populations to further assess changes induced by this autologous DC therapy as CD40L is a major B cell co-stimulatory factor. To this end, we assessed B cell subset changes in relation to the proliferative capacity of CD4+ and CD8+ T cells response to DC targets containing the 4 HIV-1 antigens (Gag, Vpr, Rev, Nef). The co-expression of CD19, CD38, IgD, CD10, CD23, CD27, CD5, and CD138 were analyzed by multi-parametric flow cytometry to assess circulating B cell subsets such as naïve resting B-cells (Bm1), activated naïve B cells (Bm2), GC founder cells (Bm2’), centroblasts and centrocytes (Bm3 and Bm4), early memory B cells (eBm5), memory B cells (Bm5), IgD memory cells, plasma cells, and B-1 cells. Changes in B cells subsets were analyzed before and after the four intradermal injections of this immunotherapeutic product containing 1.2 × 10⁷ DC. Ten ART treated subjects with undetectable viral load (< 50 copies/ml), median CD4+ count of 440 cells/μl (range: 316–1102), and with a CD4+ nadir > 200 cells/μl were studied. Throughout the study, no significant changes in CD4+ cell count, CD4/CD8 ratio, and no viral blips were noticed. The percentage of total B cells, Bm1, Bm2, Bm2′, eBm5, IgD memory, plasma cells, and B-1 cell subsets did not significantly change. However, a decrease in the percentage of Bm3 and Bm4 cells was found (0.36 [0.06–0.86] versus 0.11 [0.04–0.36]; P=0.05). Conversely, an important increase in the Bm5 cell subset was evidenced (10.4 [1.6–24.2] versus 18.1 [5.1–27.5]; P=0.005) suggesting a proliferation of B memory cells induced by DC immunization. In addition, the multifunctional and polyvalent CD8+ T cell proliferative responses to the 4 HIV genes used in this immunotherapy were noticed in 8 out of 9 subjects available for analysis and characterized by an effector memory phenotype. No CD4+ T cell immune responses were detected, consistent with the endogenous HLA class I loading of the antigens. Collectively, these results indicate that this immunotherapy induces an increase in the B memory cell population in the absence of inducing any clinically apparent autoimmunity along with strong HIV specific multifunctional CD8+ T cell specific immune responses.