IgG antibodies against pneumococcal polysaccharides are found predomin
antly within IgG subclass 2. We wished to evaluate retrospectively IgG
subclasses and post-immunization pneumococcal antibody titers in chil
dren with recurrent respiratory infections. We examined total immunogl
obulin levels and IgG subclasses, as well as pneumococcal antibody tit
ers against serotypes 3, 7F, 9N, and 14 present 4-6 weeks after pneumo
coccal immunization in 56 children 2-18 years old. Titers >200 ng Ab N
/ml to any of the 4 serotypes tested were arbitrarily considered prote
ctive. Four patients did not have protective antibody levels against a
ny of the 4 serotypes tested following vaccination. Of those, 3 had no
rmal IgG subclass levels and 1 had an IgG2 subclass deficiency. Of 3 a
dditional patients with IgG2 deficiency 2 had protective antibody leve
ls to only 1 serotype and 1 had protective antibody levels to 2 seroty
pes. Furthermore, in 2 patients with undetectable IgG2 at the time of
immunization, the response was only transient. We conclude that patien
ts with IgG2 deficiency may not develop protective antibody levels to
all pneumococcal serotypes and that some may have deficient memory for
IgG anti-pneumococcal polysaccharide antibodies. (C) 1996 Wiley-Liss,
Inc.