2. The subject has a primary immunodeficiency disease, which has as a significant component of hypogammaglobulinemia and/or antibody deficiency (e.g. (exempli gratia / for example), common variable immunodeficiency, X-linked and autosomal forms of agammaglobulinemia, hyper-immunoglobulin M (hyper-IgM) syndrome, Wiskott-Aldrich Syndrome). Isolated deficiency of a single IgG subclass, or of specific antibodies without hypogammaglobulinemia per se, does not qualify for inclusion.