Recently, a series of studies demonstrated an unexpected observation that deficiency in TCR signaling components may manifest immunodeficiency that accompanies autoimmunity, inflammatory diseases, and/or increased IgE production.47 Here, we report defective thymic negative selection in CBAP-deficient mice via impairment of the assembly of the LAT signalosome and disruption of TCR signaling (Figure 6). Here, IGHE is linked to immunodeficiency disease.