CD40LG and immune system disorder: Based on the diagnostic criteria proposed by the European Society for Immunodeficiencies and Pan-American Group for Immunodeficiency (age older than 4 years, serum IgG level below the lower reference range, decreased serum IgM or IgA, and exclusion of an underlying cause) [5], the patient's immune deficiency was labelled as CVID, while, according to the criteria proposed by Malphettes et al. [3], he was placed at the LOCID category/variant.