R935788 (Fostamatinib disodium) is a selective Syk inhibitor with an IC50 of 41 nM.R935788 (Fostamatinib disodium) has shown clinical activity in heavily pre-treated NHL and CLL patients, exhibits inhibitory activity against SYK but also inhibits a broad spectrum of other kinase targets. In addition to blocking FcγR-mediated events,R935788 (Fostamatinib disodium) also blocked BCR-mediated Ag presentation, thus broadly interrupting the humoral contributions to T cell-driven autoimmunity. Indeed, oral administration of R935788 (Fostamatinib disodium) significantly delayed spontaneous diabetes onset in NOD mice and successfully delayed progression of early-established diabetes even when treatment was initiated after the development of glucose intolerance. At the DC level, R788 treatment was associated with reduced insulin-specific CD8 priming and decreased DC numbers. At the B cell level, R935788 (Fostamatinib disodium) reduced total B cell numbers and total Ig concentrations. Interestingly, R935788 (Fostamatinib disodium) increased the number of IL-10–producing B cells, thus inducing a tolerogenic B cell population with immunomodulatory activity. Taken together, Syk in APCs is an attractive target in T cell-mediated autoimmune diseases such as type 1 diabetes. [1][2][3][4]