Repository corticotropin injection reverses critical elements of the TLR9/B cell receptor activation response in human B cells in vitro.

We sought evidence for direct effects of repository corticotropin (RCI; an FDA-approved treatment for selected cases of SLE) on isolated human B lymphocytes activated by engagement of TLR9 and B cell receptors. ODN 2395/αIgM treatment was found to result in induction of 162 distinct mRNAs and suppression of 80 mRNAs at 24 h. RCI treatment resulted in suppression of 14 of the ODN 2395/αIgM -induced mRNAs (mean suppression to 23.6 ±â€¯3.1% of stimulated value). The RCI-suppressed mRNAs included two critical regulators of class switch recombination, AICDA and BATF. RCI treatment also resulted in induction of 5 of the ODN 2395/αIgM -suppressed mRNAs (mean induction by RCI = 7.65 ±â€¯2.34-fold). The RCI-induced mRNAs included SLAMF3, a cell surface receptor capable of inhibiting autoantibody responses. These studies reveal that RCI treatment of human B cells reverses key elements of the early mRNA response to TLR9 and B cell receptor engagement.

Direct effects of HP Acthar Gel on human B lymphocyte activation in vitro.

INTRODUCTION: Both clinical experience and experimental evidence have suggested that Adrenocorticotropic hormone (ACTH) might directly exert immunomodulatory effects not dependent on adrenal steroidogenesis. METHODS: The direct effects of H.P. Acthar Gel (Acthar), a repository preparation containing a porcine ACTH analogue, on human B lymphocyte function were studied in vitro using peripheral blood B cells isolated using anti-CD19 coated magnetic beads and activated by interleukin 4 (IL-4) and CD40 ligand (CD40L). Analysis of expression of messenger RNA (mRNA) encoding activation-induced cytidine deaminase (AICDA) was carried out by quantitative real-time polymerase chain reaction (PCR). Cellular proliferation was assessed by a flow cytometric technique using intracellular staining with carboxyfluorescein succinimidyl ester (CFSE). Immunoglobulin G (IgG) production was measured in cell supernatants using an immunoassay. RESULTS: Acthar was found to exert acute, dose-dependent inhibitory effects on IL-4/CD40L-mediated induction of the expression of activation-induced cytidine deaminase (AICDA) after 24 hours, as well as sustained inhibition of B cell proliferation and IgG production during five more days of culture, without deleterious effects on B cell viability. CONCLUSIONS: These experiments demonstrate that Acthar can exert direct effects on the humoral immune system independent of any role in the regulation of adrenal steroidogenesis. Although the impact of these findings on clinical disease was not evaluated in this study, these data support the therapeutic potential of Acthar for the management of autoimmune diseases characterized by B cell activation and aberrant humoral immune function.