Restriction of immunoglobulin heterogeneity, autoimmunity and serum protein levels in aged people.

Ninety-one sera of persons above 80 years of age were screened flit autoantibody activity against lipoproteins (anti-LDL 7, anti-HDL 6 positive), for rheumatoid factor activity (Latex 14, Waaler-Rose 7 positive) and for antinuclear factors (11 positive). Among the sera with auto-antibody activity 29% showed deviations of the normal kappa/lambda ratio of immunoglobulins, as opposed to 22% of the sera without detected autoantibody activity. In 3% of the sera an M component was detected. Determination of the α₁-acid glycoprutein, α-antitrypsin, haptoglobin, haemopexin, complement component C₃c and C₄, IgG, IgA and 1gM levels showed significant increases in α-, and β-globulins as well as in lgG and IgA in sera of the aged persons as compared to a normal population between 20 and 60 years old. No significant difference was noted between the γ-globulin concentration in sera of aged persons with or without autoantibody activity. The evaluation of the relationship between serum protein levels and alterations of the kappa/lambda ratjo indicated that the &lapha;- and the β-globulins were significantly raised in sera with altered kappa/lambda ratios, whereas, with the exception of M component containing sera the γ-globulin levels seemed not significantly affected by changes in this ratio. [ABSTRACT FROM AUTHOR]