CD40LG and ankylosing spondylitis: Regarding family history, 25% of patients in the HS-CVID group had a positive family history of recurrent upper respiratory tract infections with levels of IgA/IgG/IgM at or below the lower limit of normal; 12.5% showed a family history related to ITP; and 50% of patients' parents had autoimmunity and allergic diseases, including ankylosing spondylitis (AS), Sjogren's syndrome (SS), and allergic rhinitis (AR).