CD40LG and Autoimmunity: However, there are several key clinical differences: CD40/CD40L deficiency results in severe opportunistic infections (due to defects in CD4+ T cell–mediated myeloid cell activation), while patients lacking AID, UNG, or CTNNBL1 exhibit follicular hypoplasia and autoimmunity (de la Morena, 2016; Ferrari et al., 2001; Imai et al., 2003; Kuhny et al., 2020; Lougaris et al., 2005; Notarangelo et al., 2006; Renner et al., 2021; Revy et al., 2000).