Serum immunoglobulin D levels by age in a healthy Italian pediatric population.

摘要

Sirs, Limited studies are currently available regarding IgD serum levels in healthy subjects and results are contrasting. In adults, considerable variations in IgD serum levels have been reported from undetectable to over 60 IU/mL (1,2). The shape of the distribution has been variously described as unimodal, bimodal or trimodal (2). Gender, human leukocyte antigens DR1 haplotype, Gm allotype, and environmental factors, such as smoking, may influence serum IgD level (2). Few investigations have been conducted in children and results may be difficult to interpret since several studies included exclusively children with an underlying disease (i.e. atopy, celiac disease, or congenital immunodeficiency) (3-6). A linear increase of IgD level with age (7), or a bimodal distribution (8). have been reported in children. No study has included southern European children. Such data may be of interest, since differences in circulating IgD concentrations have been found between adult volunteers of different ethnic backgrounds (9). Thus, we determined serum IgD concentrations among healthy Italian children, using a highly sensitive, commercially available, radio immunodiffusion method (RID). IgD serum levels were determined in 208 healthy Italian children aged 0 to 18 years undergoing venopuncture before a minor surgical elective intervention. Informed consent to the study was obtained by the parents or legal guardians. The study received local Ethical Committee approval. Serum samples were stored at -70°C until tested. Serum IgD concentrations were determined using a commercial RID assay according to the manufacturer's instructions. (Human IgD NL BINDARID kit. Binding Site Inc., Birminghan, U.K.). The lower serum concentration of IgD quantifiable was 0.5 IU/mL.