Absorption of serum proteins by inorganic dusts

Jones, B. M., Edwards, J. H., and Wagner, J. C. (1972).Brit. J. industr. Med.,29, 287-292. Absorption of serum proteins by inorganic dusts. Four samples of coal dust of different ranks, five types of asbestos, and a sample of silica were each incubated with normal serum and with IgG and the amount of protein absorbed onto the particle surfaces was estimated. The total amount of protein absorbed by the coal samples was not related to the rank of coal, and surface absorption by the dusts did not detectably alter protein to a form capable of reacting with rheumatoid factor, the latter finding being in disagreement with the hypothesis put forward by Payne (1963) to explain the presence of rheumatoid factor in the serum of a large proportion of coal workers with pneumoconiosis. Estimation of immunoglobulin levels after incubation of normal serum with 10 samples of coal suggested that IgG might be selectively absorbed, and RF was absorbed in preference to normal serum proteins by dust samples which had not been coated with normal serum.

Plasma kinin formation by complexes of aggregated gamma-globulin and serum proteins

The precipitating complexes formed by heat-aggregated γ-globulin with rheumatoid factor and other serum proteins, induce kinin formation in plasma and synovial fluids. Insoluble cross-linked aggregated γ-globulin also bound and activated kinin-forming factors. Complement inhibitors did not suppress these actions of the complexes.

Catabolism and synovial transport of rheumatoid factor

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The metabolism of autologous IgM and 19S rheumatoid factor in rheumatoid arthritis

The turnover of autologous preparations of radio-iodine labelled IgM and 19S rheumatoid factor was studied and compared in patients with severe rheumatoid disease. The IgM was isolated by block electrophoresis and column chromatography. 19S rheumatoid factor was isolated by a combination of euglobulin precipitation, column chromatography, and absorption onto and acid-elution from solid aggregated IgG.

Ten studies were made in seven patients, five with IgM, and five with 19S rheumatoid factor. In two patients the turnovers of 19S rheumatoid factor and IgM were studied simultaneously.

The turnover of IgM was similar to that reported for normal subjects and patients with other diseases: fractional catabolic rate 0·14–0·18, plasma and whole body T_½ 3·7–6·5 days, with 65–77% intravascular localization. The absolute catabolic rate for IgM was elevated (8–60 mg/kg/day).

The turnover of 19S rheumatoid factor isolated from serum was comparable in fractional catabolic rate (0·15–0·19) plasma and whole body T_½ (3·9–6·0 days) and intravascular localization (62–88%). No evidence of rapid catabolism of the `immune' elimination type was obtained.

Antinuclear factors in rheumatoid arthritis. Increasing organ-non-specificity with increasing reactivity of rheumatoid factor with heterologous gamma globulin

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