Clinical studies of seven patients with rheumatoid arthritis and uniquely large amounts of rheumatoid factor

[The pathogenic role and production system of autoantibody in rheumatoid arthritis]

Rheumatoid arthritis (RA) is an autoimmune disease that affects 1% of the population worldwide, however the pathogenic role remains elusive. Successful treatment with anti-CD20 therapy highlighted the importance of B cells in RA. Several antibodies (Abs) were identified from sera from RA patients such as rheumatoid factor, anti-CCP Abs, anti-glucose-6-phosphate isomerase Abs, anti-calpastatin Abs, anti-soluble gp130 Abs, anti-collagen type II Abs, etc. In this review, we will focus on the pathogenicity and production system of auto-Abs in RA, and also explain about recent advance from human study.

ACTIVITY OF DISSOCIATED AND REASSOCIATED 19S ANTI-GAMMA-GLOBULINS

19S anti-γ-globulins were isolated in a high state of purity from the sera of two patients with rheumatoid arthritis. Following reduction with ethyl mercaptan and alkylation by iodoacetamide, fragments were produced which retained the capacity to combine with 7S γ-globulin. The fragments from one of the 19S anti-γ-globulins agglutinated red cells coated with incomplete anti-Rh antibodies. This activity was shown by density gradient ultracentrifugation to be associated with low molecular weight fractions. The agglutination of the coated red cells by the fragments was strongly inhibited by normal and myeloma 7S γ-globulins and showed a greater specificity than the parent 19S material. Analytical ultracentrifuge experiments demonstrated that the fragments from either of the 19S anti-γ-globulins formed complexes with 7S γ-globulin. Reassociation of the dissociated fragments through reformation of disulfide bonds resulted in the formation of fast sedimenting molecules having properties similar to those of the untreated 19S material in respect to precipitation with aggregated γ-globulin and agglutination of coated red cells.

Rheumatoid factors in subacute bacterial endocarditis and other infectious diseases

Rheumatoid factors (RF) occur during the course of various infections such as leprosy, infective endocarditis, tuberculosis, trypanosomiasis, visceral larva migrans, infectious mononucleosis, influenza A, hepatitis A or cytomegalovirus. When first described it seemed logical to assume that host-self-immunization with autologous immune complexes provided the initial stimulus for RF production. Subsequently extensive characterization of bacterial, parasitic and viral Fc receptors has suggested an alternative explanation for rheumatoid factor associated with infections. It seems possible that patients make an initial immune response to infecting agent Fc receptors and that anti-anti-Fc receptors or anti-idiotypes either then directly stimulate rheumatoid factor production or are themselves rheumatoid factors. Such a hypothesis might also be applied to rheumatoid arthritis itself where either infecting agent or autologous cell Fc receptors could be the initial immunizing epitopes involved in rheumatoid factor production.

Suppressor T cell function in patients with rheumatoid arthritis complicated by vasculitis

Concanavalin A (Con A)-induced suppressor T cell activity was determined in 10 rheumatoid arthritis (RA) patients with vasculitis, 34 RA patients without vasculitis, and 10 healthy individuals. The percent Con A-induced suppression in RA patients with vasculitis was 24.6. In contrast, it was 68.4% in those RA patients without vascular lesions. Further, the proportion of T cells reactive with OKT8 monoclonal antibody was also decreased in RA patients with vasculitis. Accordingly, the reduced Con A-induced suppressor T cell activity in these RA patients resulted, in part, from the reduction in the number of cells of the suppressor T cell subset. Those patients with vascular lesions also had a higher percentage of positive antilymphocytotoxic antibodies than RA patients without vasculitis. Since the differences in Con A-induced suppressor T cell activity and frequency of positive antilymphocytotoxic antibodies were so great, we believe RA patients with vasculitis could be recognized as a disease group distinct from RA patients without vasculitis.

The rarity of Felty's syndrome in blacks

Evidence is presented that Felty's syndrome (FS) is rare among black patients with rheumatoid arthritis (RA). All of 12 patients with FS seen at Parkland Memorial Hospital, Dallas, Texas betwen 1964 and 1978 were white. During this period 52% of patients admitted to the Parkland medical service were black and 31% of patients dischargd with a diagnosis of RA were black. The number of expected black cases of FS on the basis of the racial distribution of hospitalized patients with RA was 3.7 (P is less than 0.02 when the zero incidence in blacks was compared with the expected incidence). All 7 cases of FS observed at Charity Hospital, New Orleans, Louisiana between 1968 and 1978 were also white. During this period, 65% of patients discharged with a diagnosis of RA were black, and the number of expected black cases of FS was 4.5 (P is less than 0.001). These findings suggest a genetic basis for the development of leukopenia and splenomegaly in RA patients.

Characterization of the gamma-globulin complexes present in certain sera having high titers of anti-gamma-globulin activity

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