The association of serum IgM and IgG levels with the number of X chromosomes in patients with abnormal number of X chromosomes.

The following attributes of the immune response were studied from nine patients with different numbers of X chromosomes: serum immunoglobulin levels, C3 and C4 concentrations, the presence of autoantibodies, phagocytosis, killing of bacteria, the chemotactic response of neutrophils, the in vitro response of lymphocytes to PHA, ConA, PwM, PPD and oidiomycin; and the proportion of T lymphocytes was determined. The number of X chromosomes varied from one (45,X) to four (48,XXXX). No evidence of severe dysfunction in the immune system was found in any of the patients. The correlation coefficients between the serum concentration of IgM and IgG and the number of X chromosomes present were statistically significant (r = 0.691, P less than 0.05, and r = 0.714, P less than 0.05, respectively). The serum IgA concentration showed a tendency towards a negative correlation. The concentrations of neither IgD nor IgE correlated to the number of X chromosomes. It seems obvious that the number of X chromosomes is positively associated with the concentration of serum IgG and IgM. The results support the hypothesis that antibody production is at least partially controlled by genes located in the X chromosome.