In normal adult serum, the approximate percentage composition of IgG with respect to its subclasses is IgG1:65percent, Ig2:23percent, IgG3:6percent, and IgG4:6percent. Abnormal levels of one or more subclasses may be associated with autoimmune, anaphylatic and gut diseases, as well as with recurrent infection. Single arc by IEP against antisera to whole human serum and human IgG. No reaction to antisera to human IgA, IgD, IgE, or IgM. Prepared from plasma shown to be non reactive for HbsAG, anti-HCV, anti-HBc, and negative for anti-HIV 1 & 2 by FDA approved tests. >95percent pure by SDS-PAGE.