Profile and cross-reactivities of antiphospholipid antibodies in systemic lupus erythematosus and syphilis.

Antiphospholipid antibodies have been determined in two groups of 48 sera from patients with systemic lupus erythematosus (SLE) and syphilis. Using an ELISA, IgG anticardiolipin (CL), antiphosphatidyl serine (PS) and antiphosphatidyl ethanolamine (PEA), antibodies have been detected with the same frequency in both groups of patients. Titres of antiphosphatidyl serine (PS) (p less than 0.005) and PEA antibodies (p less than 0.05) were significantly higher in the syphilitic sera compared to the SLE sera. Anticardiolipin binding activity of both groups of sera could be inhibited by preincubation with phosphatidic acid, phosphatidyl serine, phosphatidyl glycerol and cardiolipin antigens, but the inhibiting ratio of phosphatidyl antigen was significantly higher (p less than 0.01) in the SLE group. These data suggest that anticardiolipin auto-antibodies present in SLE sera are very similar to the "reagins" or antibodies to cardiolipin seen in syphilitic sera. IgG anticardiolipin antibodies may be an epiphenomenon and are probably not implicated in the pathogenesis of the thrombotic diathesis seen preferentially in some patients with SLE.

Anti-mitochondrial type 5 antibodies and anti-cardiolipin antibodies in systemic lupus erythematosus and auto-immune diseases.

Twenty sera from patients with systemic lupus erythematosus (SLE) and high titre of IgG anti-cardiolipin antibodies (ACA) were studied in order to evaluate the prevalence of anti-mitochondrial type 5 antibodies (AMA 5). None of these sera were found to be AMA 5 positive but five of 18 were positive for VDRL. Twenty sera from patients with AMA 5 were studied in order to evaluate the prevalence of ACA: only six of 20 were positive for ACA. In contrast to this finding, 15 of the 20 sera positive for AMA 5 were also positive for VDRL (P less than 0.001). The six sera positive for ACA and AMA 5 were absorbed with cardiolipin micelles. This absorption eliminated the ACA activity but not the AMA 5 activity. Despite the clinical similarities between the two groups of patients with AMA 5 or ACA, these data suggest that patients with AMA 5 and patients with ACA belong to two different subsets of SLE or SLE-like syndromes and that AMA 5 antigen is different from cardiolipin.

[Anti-keratin antibodies. A marker of progressive rheumatoid arthritis]. / Les anticorps anti-kératine. Un marqueur des polyarthrites rhumatoïdes évolutives.

Anti-keratin antibodies have been detected by indirect immunofluorescence on rats esophageal sections in 122 rheumatoid polyarthritis, 100 seropositive and 22 seronegative. The frequency of anti-keratin antibodies is 58 p. cent in seropositive rheumatoid polyarthritis and 41 p. cent in seronegative rheumatoid polyarthritis. Anti-keratin antibodies have a very good specificity (96 p. cent) for rheumatoid polyarthritis since in a group of 105 controls, only 4 sera were found to have a low titre of anti-keratin antibodies (1 ankylosing spondyloarthritis, 2 sclerodermis, 1 healthy subject). The mean titre of antikeratin antibodies is higher in seropositive rheumatoid polyarthritis than in seronegative rheumatoid polyarthritis. Within seropositive rheumatoid polyarthritis, the titre of anti-keratin antibodies is correlated with the titre of rheumatoid factors determined by the latex test (r' = 0.464, p less than 0.01). The presence of anti-keratin antibodies is correlated with the degree of functional handicap evaluated by the functional index of Steinbrocker (p less than 0.02) and with the biological evolution evaluated by the sedimentation rate (p less than 0.001). No correlation was found with accidents of intolerance to fundamental treatments (gold salts, D-penicillamine), especially skin diseases. Anti-keratin antibodies represent therefore a diagnostic marker for seropositive rheumatoid polyarthritis as well as seronegative ones and an evolutive marker of seropositive rheumatoid polyarthritis.

[Antiphospholipid antibodies, thrombosis and lupus disease. Value of the assay of anticardiolipin antibodies by the ELISA technic]. / Anticorps anti-phospholipides, thromboses et maladie lupique. Intérêt du dosage des anticorps anti-cardiolipine par la méthode ELISA.

The authors have developed a sensitive immunoenzymatic method for assaying anti-cardiolipin antibodies in the serum of patients with lupus (SLE). These antibodies were present in the serum of 43/108 SLE patients, particularly in those patients with either false syphilis serology (p less than 0.02) or circulating anticoagulant (p less than 0.05). The mean titre of anti-cardiolipin antibodies was higher in the group with positive VDRL (less than 0.03). The anti-cardiolipin antibody titre was independent of the anti-native DNA antibody titre, but there was a correlation with the anti-denatured DNA antibody titre (p less than 0.02). This correlation can be partially explained by the antigenic similarity (phosphodiester bridge) between the two molecules. The preliminary clinical studies have not shown any correlation between the presence of anti-cardiolipin antibodies and the presence of signs such as thrombocytopenia, haemolysis, cerebral vascular accident, venous thrombosis, recurrent abortion. A longitudinal study of certain patients suggests that the anti-cardiolipin antibodies may disappear at the time of thrombotic accidents, which induces fixation of these antibodies to a platelet or vascular target and as a result of corticosteroid therapy.

[IgG-type antihistone antibodies. Diagnostic value in rheumatoid polyarthritis, scleroderma, spontaneous and drug-induced lupus]. / Les anticorps anti-histones de type IgG. Valeur diagnostique au cours de la polyarthrite rhumatoïde, de la sclérodermie, de la maladie lupique spontanée et médicamenteuse.

IgG anti-histone antibodies were detected by indirect immunofluorescence in 6 out of 70 sera from rheumatoid arthritis with antinuclear factors, in 1 out of 13 from scleroderma, in 14 out of 25 from spontaneous systemic lupus erythematosus (SLE) and in 11 out of 14 from drug induced lupus. Rheumatoid arthritis patients with IgG anti-histone antibodies were characterized by the severity of joint involvement and by the high frequency of extraarticular features of the disease. SLE patients with anti-histone antibodies only differed from patients without such antibodies by a higher frequency of Raynaud phenomenon (p less than 0.05). Longitudinal studies of spontaneous SLE showed that IgG anti-histone antibodies correlated with disease activity (p less than 0.001). A significant correlation was demonstrated between anti-histone IgGs and anti-ds-DNA antibodies assessed by the Farr binding assay (p less than 0.0001). IgG anti-histone antibodies were rarely found in sera from patients with drug induced antinuclear antibodies without symptoms of SLE (1 out of 6 sera). In drug induced lupus, IgG anti-histone antibodies were found in the absence of high titers of anti-ds-DNA antibodies, and this discrepancy appeared to suggest the diagnosis of drug induced lupus. Finally, anti-histone antibodies were present in 5 out of 7 sera from acebutolol induced lupus.

'In vitro' study of a reaction between the complement system and cellular DNA.

A direct reaction between the complement system and DNA in nuclei was demonstrated in vitro by an indirect immunofluorescence technique using cryostat-cut sections of rat liver as a substrate. This reaction occurred at physiological conditions of pH and molarity and was abolished by pre-treatment of the tissue sections by DNase. It begins by the fixation of C1q and involves the fixation and probably the activation of apparently all the components of the classical pathway of the complement system. The pattern of fluorescence given by this reaction was similar to the pattern given by anti-DNA antibodies present in sera from systemic lupus erythematosus (SLE) patients.

[Diagnostic value of synovial membrane immunofluorescence]. / Valeur diagnostique de l'immunofluorescence de la membrane synoviale.

The immunofluorescent study of 93 synovial membranes of persons suffering from various types of arthropathy has shown that the only element sufficiently specific to have real diagnostic value is the presence of cells with a fluorescent cytoplasm. This appearance was in fact found in 63% of the cases of rheumatoid arthritis, irrespective of their being either seropositive or seronegative, in 69% of the cases of probable rheumatoid arthritis, in only 15% of the unclassified cases of arthritis, in 28% of the cases of various types of arthritis (20% with exclusion of a case of mixed connectivitis and of a case of Waldenström's macroglobulinemia with rheumatoid arthritis) and in 0% of the cases of mechanical arthropathy. The results of immunofluorescent examination compare favorably with those of standard histology: the classical histologic appearance of rheumatoid synovitis with a node-forming tendency of the infiltrate was observed in only 36% of the verified cases of rheumatoid arthritis, while immunofluorescence was positive in 63% of the cases in this group. In the category of unclassified arthritis, these percentages were comparable, viz. 19% and 20%, repectively. The presence of cells with fluorescent cytoplasm during immunofluorescent examination of the synovial membrane may be regarded as an additional criterion supporting the diagnosis of rheumatoid arthritis.

[Anti-deoxyribonucleic acid antibodies: comparison of results provided by 3 research methods]. / Anticorps anti-acide désoxyribonucléique: comparaison des résultats fournis par trois méthodes de recherche

Three methods of determination of anti-DNA antibodies were compared. The indirect immunofluorescence method after exposure to animal DNA (IF) and Farr's radio-immunological method with bacterial DNA labelled with C14, gave highly similar results, although there were some cases in which Farr's method gave a negative and the IF method a positive result. In part, this discordance appears to be accounted for by the variable affinity of the anti-DNA antibodies for DNA. The counter-immuno-electrophoresis method (CIEP) on the other hand, gave very different results: positive reactions in a large proportion of normal sera and a considerable proportion of false-positive and false-negative results in disseminated lupus erythematosus. It is concluded that until the CIEP method is made more reliable by technical refinement, determination of anti-DNA antibodies may be carried out by either the IF or the radio-immunological method, but a double-check, by application of the two methods at the same time, is highly advisable.

Ribonucleoprotein (RNP) soluble nuclear antigen: demonstration of its reaction with serum antibodies by counter-immunoelectrophoresis and further partial characterization.

The soluble ribonucleoprotein nuclear antigen reactive with specific antibodies present in sera from patients with Mixed Connective Tissure disease has alpha 2-beta 1 electrophoretic mobility, thus enabling its reaction with specific serum antibodies to be studied by counter-immunoelectrophoresis. Its molecular weight determined by elution from a calibrated Sephadex G-200 gel column is about 175,000. Its purification has been attempted by successive DEAE cellulose chromatography, Sephadex G-200 gel filtration and Hydroxyapatite chromatography. Polyacrylamide gel electrophoresis of RNP antigen-containing fractions showed persistent heterogeneity which could be due either to inadequate purification or to dissociation of the RNP-antigen during electrophoresis.

[Direct reaction between complement system and cell nuclei (author's transl)]. / Réaction directe du complément avec les noyaux cellulaires

A direct in vitro reaction between complement system and cell nuclei of human leucocytes and of cryostat sections of rat liver or kidney, has been demonstrated by an indirect immunofluorescence technique. The first step of this reaction involves a fixation of C1q to the nuclear DNA as shown by the peripheral distribution of the fluorescence and by the extinction of the fluorescence when the tissue-slices are pretreated by DNase but not by RNase or trypsin. This fixation gives rise to an activation of C1 which can be demonstrated by the capacity of the fixed C1 to induce a fixation of C4 of the same distribution. Although the sequential fixation experiments have not allowed to establish directly the fixation of the following components of the complement system (C2 and C3), the positive results obtained using whole fresh normal human serum as a source of complement and a fluorescent anti-human C3 serum clearly indicate that the activation of the classical pathway by whole cells DNA can go as far as the C3 step. All these results were obtained at physiological pH and molarity: this can suggest a physiopathological meaning for this reaction.