Epigenetic modifications/factors are heritable changes in gene activity and expression that occur without alteration in genomic DNA sequences. Epigenetic changes lead to the modulation of intrinsic gene activates, which are ultimately responsible for protein translation and cellular activities. In B cells, microRNAs are epigenetic factors that modulate the expression of Aicda, which is essential for Ig class switch DNA recombination (CSR) and somatic hypermutation (SHM), and Prdm1, which is important for plasma cell differentiation, and therefore antibody responses. MicroRNAs bind to complementary sequences within the 3′ untranslated region (3′ UTR) of their target mRNAs causing negative regulation of protein expression in the post-transcriptional
