IGHG3 and Autoimmunity: Univariate analyses demonstrated that restricted response to certain S. pneumoniae polysaccharide antigens was associated with increased prevalence of atopy (serotypes 4, 14, 56, and 68), other allergies (serotypes 3 and 51), and autoimmune condition(s) (serotypes 3 and 51) and with a predominance of male gender in patients with subnormal IgG3.