MyD88 and FcR common gamma chain (Fcer1g, FcRγ) elicit proinflammatory responses to exogenous antigens. Deletion of these receptors in autoimmune models has generally led to reduced overall disease. In B cells, Myd88 is required for anti-DNA and anti-RNA autoAb responses, while Fcer1g is not expressed in these cells. The roles of these receptors in myeloid cells during B cell autoimmune activation remain less clear. To investigate the roles of Myd88 and Fcer1g on non-B cells, we transferred anti-self IgG (rheumatoid factor) B cells and their physiologic target antigen, anti-chromatin Ab, into mice lacking Fcer1g, Myd88 or both and studied the extrafollicular plasmablast response. Surprisingly, we found a markedly higher and more prolonged response in the absence of either molecule, an effect that was accentuated in doubly-deficient recipients, with a 40-fold increase compared to WT recipients at d10. This enhancement was dependent on CD40L, indicating that Myd88 and FcRγ, presumably on myeloid APC, was required to downregulate T cell help for the EF response. To extend the generality we then investigated a classic T cell dependent response to NP-CGG and found a similar effect. These results thus reveal novel regulatory roles in the B cell response for receptors that are typically proinflammatory.