Quantification by ELISA of erythrocyte-bound C3 fragments expressing C3d and/or C3c epitopes in patients with factor I deficiency and with autoimmune diseases.

A sensitive ELISA assay for quantifying erythrocyte (E) bound C3 fragments was developed. The assay employs a double-antibody sandwich technique, using polyclonal anti-C3d or anti-C3c antibodies to quantify C3 fragments, expressing C3d and/or C3c epitopes in washed, detergent-solubilized E. The assay detected 50-120 molecules of C3d per E in healthy individuals. Antigens reacting with anti-C3c antibodies were also detected on E from normal individuals, but the density of C3c-epitopes was 0.9-2.4 times lower than that of C3d-epitopes. In 2 patients with congenital factor I deficiency significantly increased density of E-bound C3c- as well as C3d-antigen was observed. Plasma infusion in one of the patients induced a loss of E-bound C3c-antigens, indicating cleavage of E-bound C3b to iC3b and further to C3c and E-bound C3d. Loss of C3c-antigens also occurred following in vitro treatment with normal human serum of E from one of the patients. Two thirds of 22 patients with systemic lupus erythematosus (SLE) and of 18 patients with rheumatoid arthritis had significantly increased density of E-bound C3d, the highest density being 490 C3d molecules/E in an SLE patient. The density of E-bound C3d correlated with the plasma-C3d concentration, indicating that the coating of E with C3d reflects the degree of complement activation.

Independent status for hospital medical staffs: no cause for antitrust alarm.

In recent years, there has been a growing controversy surrounding the issue of so-called "independent status" for hospital physician staffs. During the late 1970s and early 1980s, some articles advanced the theory that any conduct creating the appearance of an independent status for the hospital staff separate from that of the hospital could generate the environment for an antitrust action. These early theories, however, failed to fully appreciate the basic nature of antitrust law and the changing role of the hospital medical staff. Indeed, the changing nature of the hospital medical staff and the current application of antitrust law strongly indicate the early theories are misplaced and the "independent status" of the hospital medical staff does not create cause for antitrust alarm.

Circadian and diurnal variation of circulating immune complexes, complement-mediated solubilization, and the complement split product C3d in rheumatoid arthritis.

Nine patients with active classical rheumatoid arthritis (ARA criteria) were studied with reference to circadian variation of immunological and clinical parameters. Complement-mediated solubilization (CMS) of immune complexes (IC) and the level of circulating IC were found to be inversely related with low CMS and increased IC levels in the morning, and vice versa in the afternoon. Bed rest and exercise did not influence these fluctuations. The C3d concentration in plasma was increased but showed no diurnal or circadian periodic fluctuations when the levels were corrected for fluctuations in plasma albumin concentration. Clinical assessment by means of pain score exhibited marked variations, with high scores in the morning, and lower in the daytime, whereas measurements of Ritchie's joint index showed no consistent pattern. The circadian variations in CMS, serum IC and clinical parameters indicate the need to collect blood specimens and perform clinical examinations of patients at a fixed time of day.

Analysis of rheumatoid factors by a biotin-avidin based isotype-specific ELISA.

A one day enzyme immunoassay for the detection of rheumatoid factors of the IgG, IgM, and IgA class is described. The assay utilizes rabbit IgG as solid-phase reactant and the biotin-avidin interaction for the coupling of enzyme to indicator antibody. Three different indicator antibodies discriminated effectively between rheumatoid arthritis patients and normal subjects. F(ab')2 fragments of goat antibodies were found best suited for the test. Rheumatoid factor activity was expressed in U/ml by comparing samples to an internal standard, which was related to the WHO international reference serum for rheumatoid arthritis. Rheumatoid factor activity (U/ml) in the IgM-specific assay showed a close correlation to the latex agglutination titer. Avidity indices estimated from the slopes of the dose response curves of test sera were significantly higher for rheumatoid arthritis patients than for a group of healthy persons, indicating a higher avidity of the rheumatoid factors in the patients' sera.

Lack of effect of tranexamic acid on rheumatoid arthritis.

In a double-blind controlled study on 45 rheumatoid arthritis patients, no effect of tranexamic acid (Cyklocapron, 4.5 g per day for 6 weeks) was found in terms of subjective or objective parameters of disease activity. Tranexamic acid did not reduce complement activation, measured by plasma concentrations of the complement C3 split product C3d. Immune complex concentrations in serum were also unaffected. We conclude that plasmin inhibitors do not reduce immune complex mediated complement activation, and they should not be used for treatment of rheumatoid arthritis.

Increased number of IgG Fc receptors on monocyte-enriched peripheral blood leucocytes from patients with rheumatoid arthritis.

The number of free Fc receptors (FcR) per cell and the association constant (Kass) for the binding of monomeric IgG were determined for monocyte-enriched peripheral blood mononuclear cells, isolated from 16 patients with active classical rheumatoid arthritis (RA) and from 15 normal healthy donors. The assay system was based on binding under equilibrium conditions of 125I-labelled monomeric rabbit IgG to monocytes purified from peripheral blood on a continuous gradient of Percoll. Monocytes from 14 untreated RA patients (6 seropositive, 8 seronegative) expressed on the average 4.8 +/- 1.3 x 10(4) FcR/cell. This number was significantly higher (P less than 0.001) than that found in the control group (34. +/- 0.7 x 10(4) FcR/cell). There was also a significant difference between the mean Kass of the RA group and the control group--2.1 +/- 0.7 x 10(8) l/mol and 2.6 +/- 1.0 x 10(8) l/mol, respectively (0.05 greater than P greater than 0.01). Two seropositive RA patients receiving systemic treatment with penicillamine expressed the same number of FcR/cell as the mean of the control group (3.6 x 10(4)). Levels of circulating immune complexes (CIC) and the complement-factor C3 split product C3d were also measured. No correlation was found between the number of FcR/cell and the concentration of C3d, but there was a weak correlation between the number of FcR/cell and the level of CIC.

The glomerular filtration rate during penicillamine therapy in rheumatoid arthritis.

Twenty-one consecutive patients (14 women and 7 men aged 35-68 years, mean age 50 years) with chronic active RNA for 2-24 years (mean 12.7 years) had a normal glomerular filtration rate (GFR) (mean value 99.8 +/- 14.8% (S.D.) of sex- and age-dependent normal value) before penicillamine treatment. All patients had previously been undergoing gold treatment; no patient had signs of renal disorder, or diabetes. GFR (total 51Cr-EDTA plasma clearance) was measured before and after 3 and 6 months' penicillamine treatment, respectively. Treatment was stopped because of side effects in 4 patients, including one with renal side effects. In the remaining 17 patients there was a mean fall in GFR of 3.8 +/- 12.5 (S.D.) ml/min during 6 months' penicillamine treatment, which was not significant. There was no correlation between individual changes in GFR and penicillamine dose. The individual changes in GFR correlated well to individual changes in plasma creatinine. Repeated determinations of plasma creatinine should be done during penicillamine treatment.

Cytogenetic studies in patients treated with penicillamine.

Cytogenetic studies were performed on bone-marrow cells from 11 patients with rheumatoid arthritis treated with penicillamine. One of the patients was studied while developing a granulocytopenia and thrombocytopenia. The findings show that penicillamine had no chromosome-damaging effect as estimated by the micronucleus test and by the number of structural chromosomal aberrations.

Questionable effects of Myocrisin in experimental arthritis in rabbits.

In 18 rabbits arthritis was induced in one knee joint by injection with 0.2 ml 3% ovalbumin 4 weeks after sensitization by 3% ovalbumin and 2 mg/ml tubercle bacilli suspended in Freunds incomplete adjuvant. Half of the rabbits were treated with Myocrisin 4 mg i.m. once a week during the experimental period lasting 4-5 months. At killing, both knee joints were examined macroscopically and microscopically. In all rabbits a distinct synovitis was found in the injected knee joint. Histologically, the changes were most pronounced in the rabbits not treated with Myocrisin. An activity index of the synovial membrane changes in the Myocrisin-treated and untreated cases was calculated to 6.3 and 3.6 respectively. Some changes were also found in the uninjected knee joints of 50% of the rabbits. In contrast to some other works, this preliminary investigation suggests that antigen-induced experimental arthritis is suppressed by gold. We feel that this model of experimental arthritis may be suitable for trying out the effect of various drugs.