Background: To meet the transfusion requirements of IgA-deficient pati
ents with anti-IgA, blood services screen random donors to identify po
tential donors of IgA-deficient blood components. New information reve
als that some IgA-deficient persons may also be deficient in IgG2 and
may be at increased risk for bacterial infections. Study Design and Me
thods: Serum samples from IgA-deficient blood donors and patients were
tested for IgG2 concentration by radial immunodiffusion using monospe
cific anti-IgG2. Results: four (9.0%) of 44 IgA-deficient blood donors
and 14 (31.5%) of 44 IgA-deficient patients had coexistent IgG2 and I
gA deficiencies. Follow-up interviews with the 4 donors who had coexis
tent IgG2 and IgA deficiencies revealed that 3 had recurrent respirato
ry infections and had been hospitalized at least once for pneumonia. T
he fourth donor did not report a history suggestive of recurrent infec
tions. Conclusion: Some blood donors, recruited specifically because t
hey are IgA deficient, may also be deficient in IgG2. Persons identifi
ed by donor screening programs as being IgA deficient should be tested
for IgG2. If deficient in IgG2, they should be evaluated for a histor
y of recurrent bacterial infections and counseled accordingly.