Selective Antibody Deficiency and Recurrent Pneumococcal Bacteremia in a Patient with Sjögren's Syndrome, Hyperimmunoglobulinemia G, and Deficiencies of IgG2 and IgG4

To the Editor: Matter et al. reported a case of IgG2 and IgG4 deficiency in a 53-year-old woman who responded with specific IgG2 antibody to active immunization with polyvalent pneumococcal vaccine.¹ Their conclusion that active immunization might be successful in all such cases overlooks an extremely important group of patients: those under two years of age. Considerable experience with Hemophilus influenzae platelet-rich plasma and polyvalent pneumococcal capsular vaccines has demonstrated a variable ability to respond to polysaccharide antigenic determinants as a function of age.² The implication is that infants and very young children may have a normal maturational delay.