Abstract • 88

The most common immunodeficiencies associated with recurrent respiratory tract infections are B-cell deficiencies. Abnormality of B-cells can be seen in either quantitative deficiencies in Ig isotypes and/or IgG subclasses or deficiencies in functional antibody responses to specific antigens. The purpose of this study was to report a child presenting with recurrent respiratory infection since 4 months of age with a positive family history i.e. a paternal grandmother and a great-aunt with life long recurrent respiratory tract infection, and a paternal male cousin deceased at two months of age from an asthma attack complicated with infection. The patient is a 30 month old male who has had recurrent respiratory infections after entering day care at 4 months of age initially presenting as otitis media. Since then, in addition to otitis media, he has had sinusitis and bronchiolitis as often as 1-2 episodes in a month. He has received continuous antibiotic treatment, had two ear-tube placements bilaterally and he has developed asthma at 6 months of age requiring albuterol and cromolyn therapy. Both the child and his grandmother have undergone a complete immunologic evaluation. The results showed that the child's serum Ig isotypes and IgG subclasses were within normal range, except for an increased level of IgE. In contrast, his specific antibodies to diphtheria, tetanus, H. influenza type b and pneumococcus were below normal. Similarly, the grandmother had normal levels of Ig isotypes and IgG subclasses, except IgG3 was slightly increased, while specific antibodies to diphtheria were low. Immunization of the child was up to date for his age, and the grandmother had Td booster 3 weeks prior to evaluations. Based on the child's lack of the response to the antibiotic treatment, IVIG therapy was instituted as monthly infusions at the dosage of 400 mg/kg following which he has been clinically healthy over the past 4 months except for one episode of otitis media after the first IVIG infusion and an episode of RSV pneumonia after the second infusion. The findings are suggestive that IVIG replacement therapy may prevent further episodes of acute infections in patients with functional immunoglobulin deficiency which may be responsible for long term devastating complications.