Influence of sex and age on serum immunoglobulin concentrations in healthy subjects.

Cencentrations of serum-immunoglobulins IG, IgA and IgM in 440 apparently healthy subjects aged 15 to 70 years were estimated by assay against the WHO International Reference Preparation 67/97. An improved single-radial-diffusion technique was used. Sex-related differences were separately examined for each age group by means of Stusdent's t test. Except for IgA mean value of the younger males (15--24 years), which was significantly (p less than 0.05) higher than that of females, no other significant sex differences were found for IgA mean levels; in contrast, mean IgM concentrations were significantly (p less than 0.001) higher in females than in males, in all but one (55--70 years) of the age groups. Linear-regression analyses of log10 Ig concentration on age have evidenced that a significant decrease in IgM levels with age occurred only in females (r = - 0.390; p less than 0.001); on the contrary, significant increases with age occurred in IgG concentrations of males (r = 0.271; p less than 0.001), as well as in IgA levels of both males (r = 0.240; p less than , less than 0.001) and females (r = 0.263 ; p less than 0.001).