Current status of the rheumatoid factor

The effect of rheumatoid factors and of antigobulins of immune hemolysis in vivo

Studies were undertaken in man and in the rat comparing the effects of rheumatoid factors and immune antiglobulins on red cells sensitized with incomplete antibodies. The interaction of immune antiglobulins with sensitized red cells produced (a) agglutination in vitro and (b) an accelerated sequestration of the sensitized cells in vivo. In contrast, rheumatoid macroglobulins, although capable of agglutinating Rh-sensitized red cells in vitro, did not modify their destruction in vivo. The failure of rheumatoid factors to function as antiglobulins in vivo appears to reflect their non-reactivity with sensitized cells in whole serum. It is suggested: (a) that the native (7S) gamma globulins of plasma competitively inhibit rheumatoid factors from reacting with fixed antibody in the blood stream; (b) that if these macroglobulins do indeed have pathogenetic activity, this may be limited to body fluids of low protein content.

Seronegative rheumatoid arthritis, rheumatoid factor cross reactive idiotype expression, and hidden rheumatoid factors

The major rheumatoid factor cross reactive idiotype (RCRI), defined by prototypic monoclonal rheumatoid factors (RFs), is expressed as a dominant idiotype by pokeweed mitogen induced plasma cells obtained from seropositive (RF+) patients with rheumatoid arthritis (RA). Some patients who meet clinical diagnostic criteria for RA set by the American Rheumatism Association fail to express RFs at any time during their clinical course. To determine if seronegative (RF-) patients with RA, so designated by the latex fixation, Rose-Waaler classic binding assays, or a RF enzyme linked immunosorbent assay (ELISA), express the RCRI in the absence of detectable RFs we examined pokeweed mitogen plasma cells from these patients by indirect immunofluorescence. In addition, we used an inhibition ELISA to detect RCRI bearing molecules in the sera of RF- patients with RA. Five of 10 RF- patients with RA had a high prevalence of RCRI+ plasma cells (16-49% of total pokeweed mitogen plasma cells in culture). Six of 20 RF- patients with RA had high serum concentrations of molecules marked by the RCRI, equivalent to 21-110 micrograms/ml of RCRI+ reference monoclonal IgM RF. Four of five patients who expressed the RCRI in high prevalence in pokeweed mitogen plasma cells, also demonstrated high concentrations of RCRI in their sera detected by inhibition ELISA. There was significant concordance of RCRI expression determined by the two different assays. Four RF- patients with RA who expressed RCRI in their whole sera had hidden RFs detected in their 19S and, in one case, 7S serum fraction. Detection of RF related molecules in whole sera by the expression of RCRI in RF- patients with RA identifies a subgroup of RF- patients with RA who possess hidden RFs. Some RF- patients with RA can express the major RCRI in pokeweed mitogen plasma cells and in their sera and therefore are related to patients with prototypic Waldenstrom's macroglobulinaemia, who produce RCRI+ 19S IgM monoclonal RFs.

Antibody producing capacity to the bacteriophage phi X174 in rheumatoid arthritis

A study of antibody production in response to a primary immunogen, the bacteriophage phi X174, was performed in 27 patients with rheumatoid arthritis and 15 controls. All patients produced a primary (IgM) response to initial immunisation. The frequency distribution of peak antibody titres after secondary immunisation showed a marked difference between the patients and controls, with 10 patients having peak titres below 5000. The IgG component of the antibody response expressed as a percentage of total phage antibody on the 10th day after secondary immunisation was less in the patients than in the control group. There was no correlation between antibody titres and indices of disease activity, rheumatoid factor titres, or the presence of DRw4, DRw3, and DRw2. After secondary immunisation the patients with rheumatoid arthritis were treated with D-penicillamine, azathioprine, levamisole, or maintained on a non-steroidal anti-inflammatory drug. Assessment of response to tertiary immunisation again showed an impairment of antibody production in the rheumatoid group receiving non-steroidal anti-inflammatory drugs compared with the controls. None of the drugs, D-penicillamine, azathioprine, or levamisole, produced further suppression or augmentation of antibody production in response to the immunogen.

Immune system in rheumatoid arthritis: possible implications in neoplasms

Although the immune system in rheumatoid arthritis is generally in a state of hyperactivity, deficient function can be demonstrated in certain specific parts of the system. This has been most clearly demonstrated in studies of the response of blood lymphocytes from demonstrated in studies of the response of blood lymphocytes from patients with rheumatoid arthritis to in vitro infection by the Epstein-Barr virus. The virus normally infects B cells promoting proliferation. This results in the establishment of permanent lines of infected B cells more commonly than normal in rheumatoid arthritis. This condition is associated with decreased production of lymphokines, interleukin-2, and gamma interferon. Similar in vitro problems in immune responses to other antigens have also been described. Although natural killer cells are scarce among synovial cells, they are present in normal numbers in the blood. Whether these select immunodeficiencies make patients with rheumatoid arthritis more prone to neoplasms, particularly lymphomas, is a question that has not been investigated until now. Nor has it been determined whether the immune abnormalities in rheumatoid arthritis make patients more prone to neoplasms from the therapeutic agents used in their treatment.

Association of antibodies to ribonucleoprotein and Sm antigens with mixed connective-tissue disease, systematic lupus erythematosus and other rheumatic diseases

Extractable nuclear antigen contains ribo-nuclease-sensitive (ribonucleoprotein) and ribonuclease-resistant (Sm) components. To determine the diagnostic usefulness of antibodies to these antigens, a multicenter study was undertaken in which serums were analyzed for these antibodies and the findings compared with clinical and other laboratory characteristics of the patients. Of 100 patients with hemagglutinating antibodies to ribonuclease-sensitive extractable nuclear antigen, and only the same antibodies by immunodiffusion, 74 per cent had typical features of mixed connective-tissue disease; 12 features of systemic lupus erythematosus, eight those of scleroderma and six an undifferentiated mild connective-tissue disease. Of 27 patients with hemagglutinating antibodies to ribonuclease-resistant extractable nuclear antigen (and Sm antibodies by immunodiffusion), 85 per cent had typical systemic lupus. Thus, antibodies to nuclear ribonucleoprotein and Sm are of diagnostic use; if the serum contains only ribonucleoprotein antibody in high titer, it is likely that the patient has mixed connective-tissue disease.

Coexistence of ankylosing spondylitis and rheumatoid arthritis

Ankylosing spondylitis and rheumatoid arthritis share many common features. However the presence of rheumatoid factor, histologically classic rheumatoid nodules, and the histocompatibility cell wall antigen (HLA-B27) helps distinguish one from the other. Two cases are reported in which these features established the coexisting diagnoses of ankylosing spondylitis and rheumatoid arthritis.

Chemotaxis of polymorphonuclear leukocytes from patients with rheumatoid arthritis

Using a new in vitro method of measuring the chemotaxis of polymorphonuclear leukocytes from peripheral blood, a chemotactic index has been calculated. The mean chemotactic index of 320 in 24 patients with definite rheumatoid arthritis, was significantly less (P < 0.0005) than the mean of 555 in 24 normal controls matched for age and sex. The mean chemotactic index of 435 in eight patients with juvenile rheumatoid arthritis was also significantly less (P < 0.01) than that of 553 in similarly matched controls. The chemotactic index could not be correlated with age, sex, disease activity, drugs used in treatment, latex titer, immunoglobulin levels, or protein coating on the cells. However, there was a correlation between the chemotactic index and the serum complement B(1e)/B(1a) value (P < 0.01) in 17 patients with adult onset rheumatoid arthritis. Although the serum complement B(1e)/B(1a) values were within the normal range, the lowest chemotactic indices were associated with the lowest complement values. The chemotactic indices in three patients with severe connective tissue disease (seropositive rheumatoid arthritis, systemic lupus erythematosus, and polymyositis) returned to normal after 5 days' treatment with 60 mg of prednisolone per day. Incubation of the cells from patients with rheumatoid arthritis with hydrocortisone in vitro failed to alter the chemotactic indices. Prior incubation of normal cells with purified rheumatoid factor complexes, rheumatoid serum, or macromolecules of iron dextran impaired their chemotaxis. It is suggested that phagocytosis of complexes in vivo is a possible mechanism by which the chemotaxis of the polymorphonuclear leukocytes of patients with rheumatoid arthritis is impaired. This impairment in chemotaxis may explain the increased incidence of bacterial infection, both during life and as a cause of death in these patients.

Catabolism and synovial transport of rheumatoid factor

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