CD4 and idiopathic CD4 lymphocytopenia: Furthermore, the identification of a novel mechanism causing severe depletion of CD4 T-cells may suggest a potential role of auto-antibodies in ICL, HIV-1 infection, and other autoimmune diseases associated to a not yet explained reduction of CD4 T cells [i.e., Sjogren syndrome or systemic lupus erythematous (SLE)] (12).