High Levels Of Rheumatoid Factor Research Articles

Determination of immunoglobulin M antibodies for hepatitis B core antigen with a capture enzyme immunoassay and biotin-labeled core antigen produced in Escherichia coli.

A new capture enzyme immunoassay for the determination of immunoglobulin M (IgM) antibodies against hepatitis B core antigen (HBcAg) is described. Core antigen produced in Escherichia coli was labeled with biotin and subsequently detected by an avidin-biotin-peroxidase complex. The biotin-labeled core antigen was effective at concentrations as low as 20 ng/ml. Of 561 serum samples from different groups of patients that were tested, 465 samples were negative for other hepatitis B virus markers and also for anti-HBcAg IgM. Sera from the early stages of hepatitis B infection had high levels of anti-HBcAg IgM, and a clear correlation with the acuteness of the disease was observed in 45 follow-up sera from 23 patients with acute or recent hepatitis B. Sera from 21 patients with past hepatitis B were all negative for anti-HBcAg IgM. Twenty serum samples from chronic carriers of hepatitis B surface antigen showed slightly elevated antibody levels for anti-HBcAg IgM. Ten sera which were positive for anti-HBcAg IgG antibodies and had high levels of rheumatoid factor were negative for anti-HBcAg IgM.

Clinical evaluation of the sensitivity and specificity of a commercially available enzyme immunoassay for detection of rubella virus-specific immunoglobulin M.

A solid-phase capture antigen enzyme immunoassay (Rubazyme-M) was evaluated for sensitivity and specificity on sera from 1,200 blood donors, 51 patients with rubella, 2 infants with congenital rubella, 104 patients with other infections, and 126 patients with immunological abnormalities. The sensitivity was 100% for sera tested between days 3 and 40 after the onset of symptoms of rubella virus infection. Rubella virus-specific immunoglobulin M was detected at birth in sera from congenitally infected infants and persisted for several months. Positive Rubazyme-M responses were observed in some patients in the absence of rubella diagnosis (one blood donor, three other infections, and two immunological abnormalities), providing a test specificity of 99.6%. None of 67 patients with rubella virus-specific immunoglobulin G antibody and high levels of rheumatoid factor were positive in the test.

Complement-activating rheumatoid-factor-containing complexes in patients with rheumatoid vasculitis.

The role of complement and rheumatoid factor in immune complexes was examined in patients with a variety of rheumatic diseases. This was done by assessing the amount of rheumatoid factor (RF) bound from sera by F(ab)2 anti-C3 attached to a solid matrix. High levels of RF bound to C3 were detected in patients with rheumatoid arthritis complicated by vasculitis but rarely and in lower levels in patients with synovitis, ankylosing spondylitis, and systemic lupus erythematosus. The activity was bound to anti-C3 through anti-C3 antibodies because little was bound by normal F(ab)2 and was evidently complexed in the sera before in-vitro testing, since it was precipitated by 2 . 5% polyethylene glycol and sedimented with high molecular weight material on sucrose density gradient ultracentrifugation. It is considered that RF-containing complexes are present in vasculitic sera and have the potential to bind complement in vivo.

Detection of infectious mononucleosis heterophil antibody by a rapid, standardized enzyme-linked immunosorbent assay procedure

A rapid, specific, sensitive, standardized, a reproducible enzyme-linked immunosorbent assay (ELISA) procedure has been developed for detecting the heterophil antibody associated with infectious mononucleosis (IM). The IM heterophil antibody used for the solid phase was purified from bovine erythrocyte stroma. The test uses heavy-chain-specific anti-immunoglobulin M (IgM) labeled with alkaline phosphatase and three 10-min incubations. The quantitative results correlated well with horse erythrocyte agglutination titers. Absorption tests confirmed the specificity of the ELISA reactions for IM heterophil antibodies. Neither very high levels of IgM in myeloma sera nor high levels of rheumatoid factor caused false-positive reactions. A number of probable IM cases were encountered which positive by ELISA but negative by the horse erythrocyte slide agglutination test. Absorption studies indicated that these were true-positives for the IM heterophil antibody. The IM heterophil antibodies were confirmed to be predominantly of the IgM class, but moderate proportions of the IgM class were sometimes encountered.

Detection and measurement of rheumatoid factor using a new immuonenzymatic technique with peroxidase/anti-peroxidase complex

A new, solid-phase enzymatic technique is proposed for the detection and measurement of rheumatoid factors (RF). A complex (PAP) consisting of peroxidase and rabbit IgG anti-peroxidase antibodies was used as antigen. The sensitivity of the technique is such that even ⪡ physiological ⪢ levels of RF may be detected in the majority of serum samples. The intra-assay and inter-assay repeatability (6–8% and 12%) is better than that for either of the traditional agglutination techniques (latex fixation test and Waaler-Rose reaction, or LWR) and this means that the serological evolution of the illness may be followed more accurately for each patient. The detection of non-agglutinating RF was also possible. The antigen used ( i. e. rabbit IgG) was fixed immunologically to the enzyme, hence it was not denaturated by chemically labelling. This antigen resembles that of the Waaler-Rose reaction. A variation of this method enabled the detection of RF immunoglobulin class, when only the IgM fraction of the sera tested could be fixed to the solid phase by means of anti-μ F(ab′) 2 antibody before introduction of the antigen. The affinity constant could be measured without antibody purification. In 211 cases of adult rheumatoid arthritis, abnormally high levels of RF were revealed in 78 % of the subjects using the PAP technique and in only 53 % with the agglutination (LWR) techniques. On the other hand, the RF levels were within normal limits in the 51 cases of other inflammatory rheumatisms lacking RF according to the LWR techniques, in 62 cases of non-inflammatory diseases (hip osteoarthrosis, low back pain) and also in the 42 cases of other inflammatory diseases.

Common serological features in rheumatoid arthritis and yersinia arthritis. Demonstration of rheumatoid factors and antibodies against ssDNA and Yersinia enterocolitica Lipopolysaccharide by ELISA.

Sera from 31 patients with rheumatoid arthritis (RA) and from 49 patients with Yersinia enterocolitica 0:3 infection were examined for the presence of rheumatoid factors (RF) and antibodies against denatured (ss) DNA and Y. enterocolitica 0:3 lipopolysaccharide (LPS), by using enzyme-linked immunosorbent assays. Anti-ssDNA antibodies of IgG class were found equally often in the RA as in yersinia patients. The IgM-anti-ssDNA antibody levels were also elevated in the yersinia patients, whereas the RA patients had elevated levels of IgA-anti-ssDNA antibodies. High levels of RF were seen in the RA patients and an increase in IgA-RF activity was observed during the acute stage in the yersinia arthritis patients. An overlap in the serological profiles of RA and yersinia arthritis was further seen in th results of the anti-Y. enterocolitica LPS determinations, a anti-LPS antibodies of IgG class were present not only in yersiniosis but also in 16% of the RA patients.

IgM-class rheumatoid factor interference in the solid-phase radioimmunoassay of rubella-specific IgM antibodies.

The interference of IgM-class rheumatoid factor (RF) in the solid-phase radioimmunoassay (RIA) of rubella virus IgM antibodies was studied. Acute rubella infections did not significantly activate RF. False-positive rubella antibody results were obtained, however, when patients with raised RF levels were tested. If a low rubella IgG antibody titre was present, a high level of RF was required to cause a false-positive IgM result; conversely, in sera with high IgG titres, only a low level of RF was required for interference. Although the false-positive IgM titres obtained were generally low, thet did show a positive correlation to both RF levels and rubella IgG titres. False-positive results were successfully avoided by removing the RF by absorption with heat-aggregated human gamma globulin. The absorption procedure did not affect true rubella IgM antibody titres.

Mixed cryoglobulins and glomerulonephritis.

Abstract The serum of a patient with rapidly progressive glomerulonephritis associated with mixed cryoglobulins showed sustained high levels of rheumatoid factors. Immunoglobulin (Ig) G, M, and bet...