An avidin/biotin ELISA for the measurement of serum and secretory IgD.

This paper describes an improved microtiter solid-phase enzyme immunoassay for the determination of serum and secretory IgD. Use of the interaction between biotinylated anti-human IgD and horseradish peroxidase(HRP)-avidin conjugate permits quantitation of human IgD in the range of 1-64 ng/ml. IgD was detected in all samples of serum, saliva and nasal secretions of 28 normal adults. In only one subject both serum and secretory IgD were undetectable. The mean concentration of serum IgD determined by this assay is similar to that reported by other authors using radioimmunoassay. The assay described is not only rapid and inexpensive but at least as sensitive as the radioimmunoassays usually employed for quantitation of IgD

IgE antibodies to hydrolizates of cow's milk proteins in children with cow's milk allergy.

Milk substitutes such as protein hydrolysates are largely used in children with cow milk allergy. The clinical benefit of these preparations is still a matter of debate. In the present study, IgE directed against protein hydrolysates was detected in 6/13 in children with cow milk allergy

Clinical eterogeneity and reversibility of selective immunoglobulin A deficiency in 80 children.

80 children with selective immunoglobulin A (IgA) deficiency--40 with severe deficiency (serum IgA less than 5 mg/dl) and 40 with partial deficiency (serum IgA greater than 5 mg/dl but less than minus 2 SD of the age-normal mean)--were followed up for 1.5 to 9 years; during which their serum and salivary IgA levels were measured periodically and the number and type of infections they had were recorded. In the partial deficiency group serum IgA rose to normal levels in half the group at a median age of 14 years and at a median time of 4 years after diagnosis, but they did not reach the normal range in the severe deficiency group. Pneumonia occurred more frequently in the severe than in the partial deficiency group. In addition, 11 of the 12 severely IgA deficient patients who had pneumonia had levels of both serum and salivary IgA of less than 0.5 mg/dl, and only 1 had detectable serum IgA levels. These data indicate that in childhood severe IgA deficiency is persistent and predisposed to pneumonia, whereas partial IgA deficiency is often transient and only occasionally associated with pneumonia