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We studied the surface markers Leu 7, Leu 1, Leu 2a and Leu 3a on lymphocytes of 54 healthy blood donors and 19 patients with humoral immunodeficiencies and compared the relative numbers of positive cells with the natural killer ceil (NK) activity. In controls, and in 12 out of 19 patients (group A) the percentage of the Leu 7+ cells was positively correlated with NK activity. Seven of 19 patients had increased relative numbers of Leu 7+ cells and low NK activity (group B). In controls and group A patients about 40% of the Leu 7+ cells simultaneously expressed the cell markers Leu I and Leu 2a. In group B patients approximately 70% of the Leu 7+ cells carried T cell antigens. Furthermore, a distinct suppressor T cell predominance was noticed and the large granular lymphocytes of these patients showed morphological abnormalities. [ABSTRACT FROM AUTHOR]

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]

The metabolism of the two subclasses of IgA was investigated in fourteen turnover studies in individuals with normal immunoglobulin serum concentrations. Differences in the catabolism of radioiodinated IgA1 and IgA2 myeloma proteins were found. The average biologic half-life was 5.9 days for IgA1 and only 4.5 days for IgA2. Fractional catabolic rates were 24% of the intravascular pool per day for IgA1 and 34% for IgA2. The intravascular compartment contained approximately 55% of the total body pools of both IgA subclasses. The mean IgA1 serum concentration in the individuals used for turnover studies was 2.3 mg/ml, the mean IgA2 level was 0.32 mg/ml. Synthetic rates of 24 mg/kg per day for IgA1 and 4.3 mg/kg per day for IgA2 were calculated. The low serum concentration of IgA2 results mainly from this low synthetic rate. The fractional catabolic rate of IgA2 is higher than that of IgA1. This further increases the difference between the serum concentrations of the two IgA subclasses. Quantitative determinations of both IgA subclasses were made in twenty-four sera of young male adults. The mean concentrations were 1.81 mg/ml for IgA1 and 0.22 mg/ml for IgA2. [ABSTRACT FROM AUTHOR]

Ten different antisera specific for the γ-chain of IgG were tested in gel diffusion tests and radioimmuno assays with isolated normal IgG and myeloma proteins of all four IgG subclasses. In Ouchterlony analyses, eight antisera revealed antigenic deficiency of several myeloma proteins compared to normal IgG. The most pronounced deficiency was associated with IgG4 meloma proteins. Only two antisera gave reactions of antigenic identity between normal IgG and all myeloma proteins. Radial immunodiffusion plates were prepared with four of the antisera. When normal IgG and myeloma proteins were applied at the same concentrations (1 mg/ml), areas of the precipitin discs of most myeloma proteins were larger than the discs obtained with normal IgG. The largest discs were obtained with IgG4 myeloma proteins. The same four antisera were used for a solid phase radioimmunoassay. Binding of 125I-labelled normal IgG to the insolubilized globulin fractions of the antisera was inhibited by normal IgG and myeloma proteins at various concentrations. Binding inhibition curves for normal IgG, IgGl and IgG2 myeloma proteins were similar. However, pronounced differences in binding inhibition capacity were found among the IgG3 and IgG4 myeloma proteins. It was concluded that antisera to IgG can detect immunochemical differences between normal and myeloma IgG on the one hand and between various IgG myeloma proteins on the other, and that several myeloma proteins, particularly of the IgG4 subclass, lack some of the antigenic determinants of normal IgG and other myeloma proteins. [ABSTRACT FROM AUTHOR]