High free and latent collagenase activity in psoriatic arthritis synovial fluids

Collagenase activity has been studied intensively in SF from OA and RA patients. Less is known about collagenolytic activity in PsA SF. Therefore we examined collagenolytic activity in crude and trypsin treated SF as well as the alpha 1-antitrypsin and alpha 2-macroglobulin concentrations in 50 patients suffering from OA (n = 13), RA (n = 17), and PsA (n = 20). Free collagenolytic activity was low in the crude OA SF (1.80 +/- 1.35 micrograms released collagen/min/ml SF) and almost equally low in RA SF (2.35 +/- 1.80 micrograms released collagen/min/ml SF; P > 0.3). The PsA SF, however, exhibited a significantly higher free collagenolytic activity (5.63 +/- 5.69 micrograms released collagen/min/ml SF; P < 0.05 in comparison to OA and RA SF). The treatment of the SF with trypsin further activated collagenolytic activity in each group (OA 2.17 +/- 1.35 micrograms released collagen/min/ml SF; RA 6.48 +/- 6.73 micrograms released collagen/min/ml SF; PsA 11.24 +/- 5.02 micrograms released collagen/min/ml SF) and yielded significant differences between OA and RA, OA and PsA, and RA and PsA SF (P < 0.05). Concomitantly with the collagenolytic activity, the alpha 1-antitrypsin and alpha 2-macroglobulin concentrations of the SF were measured. In SF from patients with PsA (172.9 +/- 69.4 mg/100 ml) and RA (190.6 +/- 64.7 mg/100 ml) the alpha 1-antitrypsin was significantly higher than in those from OA SF (106.1 +/- 39.2 mg/100 ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Stimulation of histamine receptors of human monocytoid and hepatoma-derived cell lines and mouse hepatocytes modulates the production of the complement components C3, C4, factor B, and C2

The influence of histamine (and the related agonists and antagonists) alone or in the presence of recombinant human interleukin 1 alpha (IL-1 alpha) and gamma interferon (IFN-gamma) was studied on the production of complement components C3, C2, factor B, and C4 in vitro with human monocytoid cell line U937, hepatoma-derived cell line HepG2, and mouse hepatocytes. Both U937 and HepG2 cells responded to histamine through H1 and H2 histamine receptors. The effect of histamine on the biosynthesis and gene expression of complement proteins was predominantly enhancing via the H1 histamine receptors and inhibitory through the H2 receptors. The actual predominance of the histamine receptor involved (and the outcome of the ligand interaction) seemed to be greatly affected by the simultaneous activation of the cells by IL-1 or IFN-gamma.

Effect of histamine on the T-cell colony formation of PHA-stimulated cells

The effect of histamine on T-cell colony formation was studied in human peripheral blood mononuclear cells. Histamine inhibited dose-dependently (10(-4)-10(-6) M) the colony formation of PHA-stimulated T-cells. The inhibition was similar in normal controls and rheumatoid arthritis (RA) patients in spite of the fact that in RA the colony formation was significantly lower than in the normal controls. No increase of colony formation was observed at low concentrations (less than 10(-7) M). Impromidine was less effective than histamine, and pyridylethylamine (PEA) was inactive. Cimetidine counteracted the effect of histamine while chlorpheniramine did not. The results show that colony formation may be inhibited through H2-receptors. This action may be of importance in cellular interactions in tissues with high local histamine concentrations.

Effect of histamine on the gene expression and secretion of complement components C2, factor B and C3 in murine macrophages--an opposite signal processing via H1 and H2 receptors

The effect of histamine on the gene expression, biosynthesis and secretion of C2, factor B and C3 was studied in mouse resident and starch elicited peritoneal macrophages. Measuring the quantity of specific mRNAs and biosynthetically labelled proteins a down-regulation of the biosynthesis of C2, factor B and C3 via H2 receptor was found. On the contrary, histamine displayed no visible H1 receptor mediated influence on the biosynthesis of C2 and factor B. However, via H1 receptor a considerably up-regulation of C3 gene expression and biosynthesis was demonstrated. The data suggest a distinct signal processing mechanism acting on H1 and H2 receptors resulting in opposite effects on the transcriptions of C3 gene in macrophages.

Effect of histamine on the gene expression and biosynthesis of complement components C2, factor B and C3 in mouse peritoneal macrophages

The gene expression and biosynthesis of C2, factor B and C3 have been investigated in vitro in mouse resident peritoneal macrophages after incubation with histamine. C2- and factor B-specific mRNA and the amount of the immunoprecipitated C2 and factor B were decreased by 10(-4) M and 10(-8) M histamine. These effects can be abrogated by the H2 antagonist cimetidine and mimicked by the H2 agonists impromidine and 4-methylhistamine. Since the H1 antagonist chlorpheniramine and the H1 agonists PEA and 2-methylhistamine have little effect on C2 and are ineffective on factor B, a strong H2 receptor dependence of the inhibition of C2 and factor B gene expression and biosynthesis is suggested. Conversely, the C3 gene expression and biosynthesis can be influenced through both H1 and H2 receptors, e.g. elevated by histamine + cimetidine, PEA and 2-methylhistamine through H1 receptors, and inhibited by histamine + chlorpheniramine, impromidine and 4-methylhistamine through H2 receptors. The data obtained by quantification of C2, factor B and C3 mRNA concentration of peritoneal macrophages suggest that the regulation of biosynthesis of these complement components by histamine in mouse peritoneal macrophages is under pretranslational control.

Action of histamine on PHA chemiluminescence response of blood mononuclear cells in autoimmune patients

Peripheral blood mononuclear cells (PBMs) of patients suffering from autoimmune diseases showed significantly lower chemiluminescence response to PHA than the controls. High doses of histamine (10(-5) M) inhibited the chemiluminescence while low doses caused a mild enhancement in all groups of patients. The preformed histamine content of the PBMs was not significantly higher in the patients than in the controls. Individually, a reverse correlation was found between the activity of the disease and the sensitivity of the cells to histamine. In very active cases, virtually no inhibition by histamine was found.

Effect of H1 and H2 agonists on the chemiluminescence of human blood mononuclear cells induced by phytohaemagglutinin

Previous results have shown a dose-dependent inhibition of the phytohaemagglutinin-elicited chemiluminescent response by histamine on human peripheral blood mononuclear cells (PBMs). The aim of the present experiments was to investigate the receptor specificity of this histamine action. The order of effectiveness of different histaminergic agonists was 4-methylhistamine greater than histamine = impromidine greater than dimaprit much greater than 2-methylhistamine greater than 2-pyridylethylamine. Cimetidine inhibited and mepyramine enhanced this effect of histaminergic agonists. The results are consistent with the view that histamine inhibits the chemiluminescent reaction of PBMs via H2 receptors. Histamine in low doses (10(-8) to 10(-10) M) stimulated the chemiluminescent reaction. Cimetidine enhanced the chemiluminescence-facilitatory action of histamine and unmasked that of 2-pyridylethylamine. It is concluded that histamine is a possible humoral modulator of PBM activity: it is inhibitory via H2 receptors.

IgE and IgE-rheumatoid factors in circulating immune complexes in rheumatoid arthritis

The sera of 21 patients with rheumatoid arthritis (RA), 11 patients with systemic lupus erythematosus (SLE), and 20 healthy subjects were analysed for the presence of IgE in immune complex fractions. These fractions were isolated by polyethylene glycol precipitation and gel filtration. Thirteen sera from RA patients contained IgE immune complexes (IC) and 11 of these were from patients with extra-articular manifestations. One SLE and none of the control sera contained such material. The serum IgE level did not correlate with IgE content of the IC fractions. Higher mean serum IgE levels were found in RA patients with extra-articular complications than in controls or RA patients with joint disease only, but the differences did not reach statistical significance. IgE anti-rabbit IgG (IgE rheumatoid factors) could be demonstrated in some IgE positive IC fractions. Antibodies to IgE, in 2 instances characterised as belonging to IgG class, were also found in ICs. This suggests the presence of anti IgE complexes. It is suggested that IgE, including some with rheumatoid factor activity, is contained in complexes which may be involved in some extra-articular manifestations of RA.

HLA-DR antigens in juvenile chronic arthritis

Twenty-five patients with juvenile chronic arthritis (JCA) were typed for HLA-A,-G,-C and -DR antigens to establish significant differences between normal controls and patients with adult rheumatoid arthritis (RA). HLA-DR antigens were correlated with subgroups of disease, and with several clinical features and immunological parameters of JCA. The frequency of DRW8 antigen was significantly higher in JCA than in normal adult controls or patients with RA. This significance was even higher in the persistent pauciarticular subgroup. Connections were found between DR antigens and clinical, immunological parameters, and some of them proved to be statistically significant. Results are presented and discussed in detail.

Measurement of immunoglobulin production by peripheral blood mononuclear cells in vitro using a solid-phase immunoradiometric assay

A simple solid-phase immunoradiometric assay for IgG and IgM is described. Supernatants from lymphocyte cultures are incubated in microtitre plates which have been precoated with anti-IgG or anti-IgM. Subsequent binding of 125I-labelled anti-immunoglobulin is measured and IgG and IgM in supernatants are estimated from the standard curve constructed for each assay. The assay is specific for human IgG and IgM, is able to detect nanogram amounts and offers advantages over other techniques for evaluating in vitro lymphocyte function.

Effect of histamine on the mitogenic response of human lymphocytes and its modification by cimetidine and levamisole

The phytohaemagglutinin (PHA) mitogenic response of human blood lymphocytes demonstrated a dose-dependent inhibition by histamine (in the range 5 X 10(-7) M). Using suboptimal mitogenic doses of PHA the suppression was more pronounced. Stimulation using different doses of pokeweed mitogen (PWM) was not altered by histamine. Purified T cells and a lymphocyte population depleted of histamine-receptor-bearing cells were less sensitive to the histamine effect. In the supernatants of histamine-stimulated cultures, suppressor factor activity was found. Cimetidine could reverse the effect of histamine in a dose-dependent manner. Adding levamisole to the PHA cultures also produced some antihistaminic effect.

Evaluation of different methods for detecting circulating immune complexes. An inter-laboratory study

Forty serum samples of healthy blood donors and 60 sera of SLE patients were tested in parallel by 7 different assays for detecting immune complexes. Significantly higher titres and significant higher incidence of positive results were observed in the patient group than in the control group in 6 tests. No test discriminated between patients in an active stage of the disease and those whose disease was inactive. Significantly higher immune complex levels were found in lupus nephritis than in the non-nephritic patients by the complement consumption test. Significant positive correlation was obtained between the results of the macrophage aggregated IgG uptake inhibition and PEG-precipitation tests and between two tests based on the interaction of the complexes with the complement system. A characteristic 'profile' of the immune complex assay was observed in the course of the repeated testings of the same patients. The results indicate that the different methods detect different types of immune complexes present in the blood of the patients.

Radioimmune double PEG precipitation technique for detecting complexed IgE

The presence of IgE in immune complex-enriched fractions prepared by 3% polyethylene glycol (PEG) precipitation was studied. The dissolved PEG-insoluble fraction was incubated with [125I]anti-IgE antibodies an then precipitated again with 3% PEG. Radioactivity in the washed pellets was taken as indicating IgE present in immune complex form. A calibration curve was constructed using artificially prepared IgE-anti-IgE complexes. The method developed may be useful to detect other components present in immune complex fractions.