Equus caballus Epigenomics

Common variable immunodeficiency (CVID) is a late-onset humoral deficiency characterized by B lymphocyte dysfunction or loss, decreased immunoglobulin production, and recurrent bacterial infections. CVID in equine patients manifest with a natural impairment of B lymphocyte differentiation in the bone marrow at the pro-B cell stage. We hypothesized that an aberrant epigenetic regulation caused PAX5 gene silencing, resulting in the late-onset and non-familial manifestation of CVID. Both genome-wide reduced-representation bisulfite sequencing and bisulfite PCR followed by sequencing methods revealed a significant increase in methylation of the PAX5 enhancer region in equine CVID patients (p<0.000).