Pediatric Systemic Lupus Erythematosus (SLE) As an Onset of Common Variable Immunodeficiency (CVID): The Double Link between Immunodeficiency and Autoimmunity

Recurrent, unusual and complicated infections are the hallmark of immunodeficiency. Primary Immunodeficiency (PID) is caused by a genetic defect impairing the immune response. Common Variable Immunodeficiency (CVID) is classified as a primary immunodeficiency with prevalent antibody defect, manifesting with respiratory and gastrointestinal infections. However, CVID is characterized by an increased prevalence of autoimmune diseases too. Here, we describe a child presenting an abnormal pattern of infections and autoimmune phenomena, fulfilling diagnostic criteria for systemic lupus erythematosus (SLE). No classified PID could be demonstrated for several years, until she developed an antibody deficiency much later than the onset of the aforementioned clinical issues. Actually, a deficit of B memory cells, being useful to classify CVID after the diagnosis is made, was evident since the first immunological investigations performed before the onset of the deficit of serum immunoglobulin. This observation supports the vision of CVID as a disorder whose primary defect cannot be limited to B cell only. That can explain the variable clinical picture of CVID, including both infections and autoimmune disorders, which can arise even before serum immunoglobulin level is compromised.