The remaining 18 patients have other isotype, light chain, or functional deficiencies with generally normal numbers of B cells [including IgG subclass deficiency with IgA and/or IgM deficiency (n = 2) [108], IgG, IgA and IgM deficiencies (n = 2) [108], partial IgA deficiency (n = 1) [124], and low IgM level (n = 1) [124]]; selective IgM deficiencies (n = 3) [81, 108]; specific antibody deficiency with normal immunoglobulin and B cells levels (n = 4) [40, 65], unspecified predominantly antibody deficiency (n = 3) [65, 95]; UNG deficiency (n = 1) [19] and APRIL deficiency (n = 1) [40]. Here, CD40LG is linked to agammaglobulinemia.