CD28 and gastroparesis: Consistent with this idea is our observation that the group of mRNAs identified in the previous study by Grover et al. that were not significantly altered in our idiopathic gastroparesis subjects, and therefore may represent mRNAs from the submucosa, were enriched for immune signaling pathways (Th1/Th2 activation, phagosome formation, B cell receptor signaling and CD28 signaling, Additional file 2: Figure S2) [10].