The Clinical Relevance of Antifibrillarin (anti-U3-RNP) Autoantibodies in Systemic Sclerosis.

Systemic sclerosis (SSc) is a heterogeneous autoimmune disease associated with several antinuclear autoantibodies useful to diagnosis and prognosis. The aim of the present multicentric study was to determine the clinical relevance of antifibrillarin autoantibodies (AFA) in patients with SSc. The clinical features of 37 patients with SSc positive for AFA (AFA+) and 139 SSc patients without AFA (AFA-) were collected retrospectively from medical records to enable a comparison between AFA- and AFA+ patients. Antifibrillarin autoantibodies were screened by an indirect immunofluorescence technique using HEp2 cells and identified by an in-house Western blot technique and/or an EliA test. Comparing AFA+ and AFA- patients, AFA+ patients were significantly younger at disease onset (36.9 versus 42.9; P = 0.02), more frequently male (P = 0.02) and of Afro-Caribbean descent (65% versus 7.7%; P < 0.001). At diagnosis, the Rodnan skin score evaluating the cutaneous manifestations was higher (13.3 versus 8.7; P = 0.01) and myositis was also more common in the AFA+ group (31.4% versus 12.2%; P < 0.01). Patients with AFA+ were not associated with diffuse cutaneous SSc or with lung involvement and no difference in survival was observed. Antifibrillarin autoantibodies are associated with patients of Afro-Caribbean origin and can identify patients with SSc who are younger at disease onset and display a higher prevalence of myositis.

Prevalence and clinical features of celiac disease in 950 children with type 1 diabetes in France.

UNLABELLED: The prevalence of celiac disease is higher in children with type 1 diabetes mellitus (DM) than in the general pediatric population, but may vary widely across countries. Sensitive and specific antibody tests are available for detecting celiac disease. AIMS: To evaluate the prevalence in France of histologically documented celiac disease in a vast cohort of children with type 1 DM, and to describe the features of celiac disease and treatment response. METHODS: Retrospective cohort study of 950 children with type 1 diabetes seen between 1994 and 2001. Antibodies to gliadin, reticulin, endomysium and transglutaminase were looked for one to seven times in each patient. RESULTS: Fifteen patients (1.6%) had biopsy-confirmed celiac disease. Symptoms led to the diagnosis in six patients (mean age, 7 years) and screening tests in nine patients (mean age, 11 years). Anti-endomysium antibodies were consistently positive. Tests for HLA-DQB1 0201 and/or 0302 were positive. Anti-endomysium antibody seroconversion was seen in two patients, 2 and 6 years, respectively, after the diagnosis of diabetes. In another patient, the biopsy became abnormal 6 years after the first positive anti-endomysium antibody test (latent form). After a mean of 3 years on a gluten-free diet, significant increases were noted in body weight (P=0.04) and insulin dose (P=0.05); clinical symptoms completely resolved in five of the six symptomatic patients. CONCLUSIONS: The prevalence of celiac disease is higher in children with type 1 DM than in the general pediatric population. Serological screening is useful for diagnosing asymptomatic celiac disease, detecting seroconversion and monitoring latent forms of disease.

Update on Anti-Saccharomyces cerevisiae antibodies, anti-nuclear associated anti-neutrophil antibodies and antibodies to exocrine pancreas detected by indirect immunofluorescence as biomarkers in chronic inflammatory bowel diseases: results of a multicenter study.

AIM: Anti-Saccharomyces cerevisiae antibodies (ASCA), anti-nuclear associated anti-neutrophil antibodies (NANA) and antibodies to exocrine pancreas (PAB), are serological tools for discriminating Crohn's disease (CrD) and ulcerative colitis (UC). Like CrD, coeliac disease (CoD) is an inflammatory bowel disease (IBD) associated with (auto) antibodies. Performing a multicenter study we primarily aimed to determine the performance of ASCA, NANA and PAB tests for IBD diagnosis in children and adults, and secondarily to evaluate the prevalence of these markers in CoD. METHODS: Sera of 109 patients with CrD, 78 with UC, 45 with CoD and 50 healthy blood donors were retrospectively included. ASCA, NANA and PAB were detected by indirect immunofluorescence (IIF). RESULTS: ASCA+/NANA- profile displayed a positive predictive value of 94.2% for CrD. Detection of ASCA was correlated with a more severe clinical profile of CrD and treatment of the disease did not influence their serum levels. ASCA positivity was found in 37.9% of active CoD. PAB were found in 36.7% CrD and 13.3% CoD patients and were not correlated with clinical features of CrD, except with an early onset of the disease. Fifteen CrD patients were ASCA negative and PAB positive. CONCLUSION: ASCA and PAB detected by IIF are specific markers for CrD although their presence does not rule out a possible active CoD. The combination of ASCA, NANA and PAB tests improves the sensitivity of immunological markers for CrD. Repeating ASCA, NANA, and PAB testing during the course of CrD has no clinical value.

Diagnostic value of anti-F-actin antibodies in a French multicenter study.

According to international criteria, autoimmune hepatitis (AIH) type 1 is characterized by the presence of antinuclear or anti-smooth muscle antibodies (SMA) with F-actin specificity. SMA have been found in 85% of AIH patients, but are not specific to this disease, and anti-F-actin specificity is not always verified when SMA are detected. The objective of this study was to determine the diagnostic value of anti-F-actin antibodies in a large population. A multicenter study involving 12 clinical centers was performed. Patients were selected on the basis of the presence of F-actin SMA detected by indirect immunofluorescence (IIF) on rat liver-kidney-stomach sections and was confirmed by IIF on Hep2 cells treated with colchicine, or F-actin dot-blot. The clinical status of patients was determined from their medical records. One hundred sixty-eight patients were included: 76% women, 24% men; mean age of 45 years (range, 2-88 years), with a bimodal age distribution. Sixty percent had AIH type 1, and 40% had another disease. In the group of women younger than 25 years, 90% had AIH type 1. Other pathologies associated with antiactin were other liver diseases (19%), including viral hepatitis C (7%), and non-liver diseases (21%), including connective tissue diseases (12%). Antibody titers were higher in AIH than in other diseases. Antiactin antibodies are of major diagnostic value in AIH, especially in young women; they may be found in other disease settings, but mostly at low levels.

Familial lupus erythematosus. Clinical and immunologic features of 125 multiplex families.

Evidence for a genetic susceptibility to systemic lupus erythematosus (SLE) in humans is based on the high concordance rate observed in identical twins and on the relatively high incidence of familial cases. Although recent genetic studies have lead to significant advances in the identification of new susceptibility genes in SLE, no large clinico-pathologic study of familial SLE has been reported to date. In the present study, we describe the main clinical and immunologic features of 125 lupus multiplex families including at least 2 cases of SLE and/or discoid lupus erythematosus (DLE), recruited through a French national survey starting in July 1997. Medical records of all affected members were reviewed by the same investigator, all available family members were interviewed using the same standardized procedure, and blood was drawn for autoantibodies typing. Clinical and immunologic features of 90 probands from multiplex SLE families were compared with those of 100 sporadic SLE patients sharing the same French Caucasian origin. The 125 lupus multiplex families included 282 affected members (2.3 patients per family); of the 125 families, 96 were of French Caucasian origin. One hundred multiplex families included 2 affected relatives, while 25 included 3 or more affected individuals. The relationship between affected members was sibs (45%), parent-offspring (31%), and second-degree (24%). An autosomal dominant mode of inheritance was strongly suggested in 1 extended pedigree with 6 clinically affected members, and a recessive pattern was suspected in 5 other families. No obvious mode of inheritance could be suspected in most of the remainder. Among French Caucasians, sex ratio, mean age at onset, and clinical and biologic SLE-related manifestations were not significantly different in multiplex compared with sporadic SLE cases. The analysis of these 125 multiplex families suggests a genetic heterogeneity that should be considered for ongoing genomic screening.

High incidence of antitissue antibodies in patients experiencing chronic liver allograft rejection.

BACKGROUND: The precise immunologic mechanisms responsible for chronic rejection of liver allografts are unknown. We have recently shown in a rodent model that recipients of liver allografts developed non-major histocompatibility complex antitissue antibodies. The aim of the present study was to test this hypothesis in the clinical setting. METHODS: Posttransplant sera of 14 patients undergoing chronic rejection and of 48 control patients (12 liver transplant patients with chronic active hepatitis or liver cirrhosis related to hepatitis C virus [HCV] infection and without chronic rejection, 10 with sclerosing cholangitis, and 26 with normal liver function tests and liver biopsy) were tested for the presence of antitissue antibodies by indirect immunofluorescence. Pretransplant sera of all these patients lacked antitissue antibodies. RESULTS: Antitissue antibodies were detected in 71% of patients who developed chronic rejection (before or at the time of chronic rejection). This incidence was significantly greater than that observed in patients not undergoing rejection (HCV-related chronic active hepatitis, 16%; sclerosing cholangitis, 0%; normal liver biopsy, 7%). All these autoantibodies were directed against the smooth muscle and/or the nucleus. In two patients, anti-smooth muscle antibodies had an antiactin or antivimentin specificity. CONCLUSIONS: These results show a strong association between chronic allograft rejection and the development of antitissue antibodies and suggest that these antibodies could be used to identify patients at high risk of developing chronic rejection after liver transplantation.

Characteristics of clometacin-induced hepatitis with special reference to the presence of anti-actin cable antibodies.

The clinical, biochemical, histopathological and immunological features of 30 cases of clometacin-induced hepatitis are described. The age range of the patients was 32-84 years with a notable female predominance of 29:1. The hepatitis was highly cytolytic with high values of transaminases but with little or no cholestasis. Gammaglobulins were higher than 18 g/l in 73% of the cases. 25 liver biopsies were performed and showed acute hepatitis with a predominant centrilobular necrosis in 17; chronic aggressive hepatitis was noted in 8 cases but 1 showed concomitant cirrhotic changes. Anti-tissue antibodies were looked for in all cases. Anti-smooth muscle antibodies of anti-actin cable type (titre 1/80 to 1/2, 560) were detected in 19 cases, anti-nucleus antibodies in 16 cases which were associated to the former in 14 cases. The above findings show that clometacin produces a hepatitis syndrome quite akin to autoimmune chronic active hepatitis (lupoid hepatitis) and to the hepatopathy induced by oxyphenisatin.

Long-term follow-up study of 164 patients with definite systemic sclerosis: classification considerations.

To evaluate the usefulness of recently proposed schemes of classification for systemic sclerosis an extensive cross-sectional study of a series of 164 consecutive patients with long-term systemic sclerosis was undertaken. There were 47 cases of proximal sclerosis, 93 of distal sclerosis and 24 of complete CREST syndrome. The study included clinical, visceral, immunological and follow-up data. In addition, a quantitative clinical score was calculated for each patient, thus providing indications for prognosis. Data were expressed according to three conventional systems of classification: The ARA system, the diffuse versus limited systemic sclerosis system and the early cutaneous involvement system. The most reliable indications of severe outcome were: proximal sclerosis, trunk skin involvement, presence of anti Scl 70 autoantibody, pulmonary and/or heart involvement and age. Diagnosis and prognosis were not generated by the same items. Prognosis indicators proved more accurate for groups than for individuals. Mortality was 1 death per 149 patient X years of follow-up from diagnosis. We conclude that the ARA criteria for classification should be recognized as a standard, but patients with complete CREST syndrome should be included in the distal group. Other systems of classification, principally 2-way versus 3-way criteria, allow different subsets of patients that correlate with prognosis and the severity of the disease, and could be used for therapeutic purposes.

[Antinuclear antibodies in primary biliary cirrhosis]. / Les anticorps antinucléaires de la cirrhose biliaire primitive.

Antinuclear and antinuclear membrane autoantibodies are detected by indirect immunofluorescence in sera of 62 p. 100 of primary biliary cirrhosis patients; when anti-SS-A (Ro) and anti-SS-B (La) autoantibodies were included, 70 percent of patients had at least one type of antinuclear antibody. Of 89 patients with primary biliary cirrhosis, 30 had either Raynaud's phenomenon, Sjögren's syndrome or the CREST syndrome. Some antinuclear antibodies, anticentromere and speckled S1 type, seem to correlate with the associated connective tissue disease. Antibodies showing the S3 pattern (multiple nuclear dots) and antibodies to nuclear membrane may be present independently of an association with connective tissue disease. In the classical technical conditions used to detect anti-tissue and anti-mitochondrial autoantibodies on tissue sections, antinuclear antibodies like anti-centromere or S3 may not be detected and/or identified. Primary biliary cirrhosis patient sera for antinuclear antibodies determination must be screened by at least two assays: indirect immunofluorescence on a human cell line, like HEp-2, and immunodiffusion. The last assay must be performed even if antinuclear antibodies are undetected by immunofluorescence.

[Hepatic function and significance of the increase in serum concentrations of IgA in alcoholic cirrhosis]. / Fonction hépatique et signification de l'augmentation de la concentration sérique des IgA au cours de la cirrhose alcoolique.

Elevated serum gammaglobulin concentrations are frequently observed in patients with liver cirrhosis. Predominant elevation of the IgA is generally considered as suggestive of an alcoholic aetiology. The aim of this study was to define the factors that determine the serum concentration of IgA in alcoholic cirrhosis. Twenty-seven patients with alcoholic cirrhosis were studied. Serum concentrations of IgG, IgA and IgM were measured by immunonephelometry. Hepatocellular function was assessed by the Child-Turcotte score, the prothrombin time and the intrinsic clearance of indocyanine green. The importance of intra-hepatic shunts was estimated according to the intact hepatocyte theory, and the degree of hepatic necrosis by serum levels of transaminases. It was noted that: 1) the IgA concentration correlated significantly with the Child-Turcotte score and with the decrease of the prothrombin time, intrinsic clearance and the functional fraction of hepatic blood flow; 2) there was no such correlation between the serum concentration of IgA and the total hepatic blood flow or transaminase levels; 3) there was no correlation between serum concentration of IgG or IgM and the factors studied. These results suggest that in alcoholic cirrhosis, increase in serum IgA, reflects the degree of impairment of hepatic function and intrahepatic shunting.

[Idiopathic portal hypertension associated with connective tissue disease similar to systemic lupus erythematosus]. / Hypertension portale idiopathique associée à une collagénose proche du lupus érythémateux disséminé.

A case of idiopathic portal hypertension associated with connective disease resembling systemic lupus erythematosus is described. The patient was a 50-year-old woman with splenomegaly, ascites, esophageal varices, and pancytopenia, but without extrahepatic portal obstruction or cirrhosis of the liver. Electron microscopy of the liver showed perisinusoidal fibrosis. High titers of autoantibodies against proliferating cell nuclear antigen (PCNA) were found in the sera as well as in ascites; anti-DNA antibodies appeared after anti-PCNA antibodies and remained thereafter at a moderate titer. The possibility of an immunological process in the pathogenesis of idiopathic portal hypertension is discussed.

[Prevalence and characteristics of anti-tissue antibodies in chronic hepatitis caused by hepatitis C virus]. / Prévalence et caractéristiques des anticorps anti-tissus au cours des hépatites chroniques dues au virus de l'hépatite C.

OBJECTIVES: The prevalence and significance of antiorganelle antibodies in the serum of patients with chronic hepatitis C is a subject of controversy. We studied prospectively these characteristics in patients with chronic hepatitis C. METHODS AND RESULTS: Among 156 patients (age: 55 +/- 14 years; 83 females), 30 (19%) had significant titers of antiorganelle antibodies: anti-nuclear antibodies in 18, anti-smooth muscle antibodies in 8 (no anti-actin or anti-vimentine subtypes), anti-LKM1 in 2, type 2 anti-mitochondrial antibodies in 2 patients. Anti-organelle antibodies were not detected in 126 patients. Patients with anti-organelle antibodies were significantly older but no difference was found between the two groups for sex ratio, serum amino-transferases or gammaglobulins, histopathological liver activity or prevalence of lymphocytic sialadenitis. The presence of anti-organelle antibodies was not related to HLA phenotype, especially B8 DR3, or DR4. Response to alpha interferon, estimated by serum aminotransferase levels after six months of treatment, was the same in both groups. CONCLUSIONS: These results suggest that serum anti-organelle antibodies are prevalent in during chronic hepatitis C but do not indicate a distinct autoimmune mechanism. Furthermore, the typing of anti-smooth muscle antibodies might help distinguish chronic hepatitis C from type 1 autoimmune chronic hepatitis.

[Analytic study of dot blotting for the detection of anti-Jo-1, anti-M2, anti-ribosomes and anti-LKM]. / Etude analytique d'un dot blot pour la détection des auto-anticorps anti-Jo-1, anti-M2, anti-ribosomes et anti-LKM1.

The Cyto-Dot 4 HM043 kit commercialised by BMD, has replaced the Cyto-Dot HM010 kit that allowed three auto-antibodies detection (anti-Jo-1, anti-M2 and anti-ribosomal protein). Detection of anti-LKM1 auto-antibody was added. These four auto-antibodies have in common only the intracytoplasmic localisation of their respective antigen. The aim of our study was to evaluate this new kit using 104 sera and to compare our results with reference techniques (indirect immunofluorescence IF for anti-M2, anti-ribosomal protein and anti-LKM1, double immunodiffusion ID for anti-Jo-1 and anti-LKM1, western blotting WB for anti-M2) and with Cyto-Dot HM010. The one hundred and four sera were divided into five groups: Group I (n = 12) with anti-Jo-1 detected by ID; Group II (n = 28) with 26 anti-M2 positive by IF and WB, 2 anti-M2 positive only by WB; Group III (n = 10) with anti-ribosomal protein detected by IF 5 of which precipitated by ID; Group IV (n = 32) with anti-LKM1 by IF and ID divided into 18 AIH2 and 14 HCV; Group V (n = 22) consisting of 14 healthy individuals and 8 patients with hypergammaglobulinemia. Results of this study are similar to those of Cyto-Dot HM010 for the three auto-antibodies already in use. Cyto-Dot 4 is a very good anti-LKM1 confirmation method as it is ID.

[Evaluation of a radioimmunologic technique for the detection of anti-native DNA antibodies]. / Evaluation d'une technique radio-immunologique pour la détection des anticorps anti-ADN natif.

The anti-native DNA antibodies were measured by a radioimmunoassay (RIA) type Farr assay in the sera from 648 patients: 108 with active or inactive systemic lupus erythematosus (SLE), 181 with clinical symptoms of another connective tissue disease, 171 with liver diseases, 29 with different pathology and 159 normal sera were obtained from a blood bank. The anti-DNA kit has been calibrated against the first international units/ml. This assay has proved to be sensitive and specific, and appears to be reliable for the diagnosis and follow-up of SLE patients. The authors propose a new reference cut-off level higher than producer's one.

[Analysis of dot-blot technique for the detection of three autoantibodies (anti-Jo-1, anti-M2, anti-ribosome). Comparison with reference techniques]. / Analyse d'une technique de dot-blot pour la détection de trois autoanticorps (anti-Jo-1, anti-M2, antiribosomes). Comparison avec les techniques de référence.

A recently commercialized dot-blot (Cyto-Dot, BMD) offered a new method for the detection of three autoantibodies (Ab) anti-Jo-1, anti-M2, and anti-ribosomal protein although their only common point is the cytoplasmic localisation of their respective antigen. These Ab are detected by indirect immunofluorescence (IF) (anti-M2, anti-ribosomal protein), double immunodiffusion (ID) (anti-Jo-1) and western blotting (WB) (anti-M2). The aim of the study was to compare results obtained by the Cyto-Dot with those obtained by our reference technique. One hundred and seventy-seven sera were analysed, divided into four groups: group I (n = 15) with anti-Jo-1 Ab detected by ID, group II (n = 70) with anti-M2 Ab by WB, group III (n = 33) with anti-ribosomal protein Ab by IF (of which, 19 are precipitating by ID), group IV (control group, n = 59) with 31 sera of healthy individuals, six sera of patients with liver diseases resembling primary biliary cirrhosis and 22 with a particular serological profile. Cyto-Dot is very sensitive and specific for the detection of anti-Jo-1 Ab. Also, it represents a reliable method (sensitivity 0.99) for the screening of anti-M2 Ab and for the confirmation of an atypic immunofluorescence pattern. Equivalent to ID for the detection of anti-ribosomal protein Ab, the Cyto-Dot represents a good alternative technique. However, although this new diagnostic method represents a sensitive technique for the detection of the three auto-Ab, unfortunately, it can not be applied for large series.

[Comparative study of serological markers for intolerance to gluten]. / Etude comparative des marqueurs sérologiques de l'intolérance au gluten.

In France as well as in most of the other European countries, the prevalence of coeliac disease is underestimated. In order to point out a good screening test, we have determined the most sensitive combination (technique-marker) for the diagnosis of the disease among 81 individuals (50 with coeliac disease and 31 controls). Serum anti-gliadin antibodies were measured using three methods: the qualitative dot-blot (Gliastick-Eurospital) and two quantitative methods Elisa (homemade-Saint-Antoine Hospital and alpha-Gliatest-Eurospital); serum anti-endomysium antibodies (EmA) and anti-reticulin antibodies (ARA) were detected using an indirect immunofluorescence assay. We have shown that the simple and fast Gliastick test can fulfil the selected criterion with a sensitivity of 0.90. Nevertheless, uncertain and positives results have to be confirmed by one of the two more specific quantitative tests. The two other markers (ARA and EmA) have shown a better specificity (1) but they were less sensitive (0.54 and 0.56 for ARA and EmA respectively). Thus, they have both to be used as confirmation tests and for follow-up with supervision of the compliance to recommended diet. In conclusion, the Gliastick can be considered as a good screening test for the detection of anti-gliadin antibodies and it would represent the expected help to determine the prevalence of coeliac disease on a large-scale map.

[Characterization of anti-mitochondrial antibodies type 2 (anti-M2): comparison of two techniques, western blotting and indirect immunofluorescence]. / Caractérisation des anticorps antimitochondries de type 2 (anti-M2): comparaison de deux techniques, immunotransfert et immunofluorescence indirecte.

About 94% of patients with typical features of primary biliary cirrhosis (PBC) have been shown to be anti-M2 positive. Today the relevance of anti-M2 antibodies as a diagnostic marker of PBC is well established. The usual method of detection is by indirect immunofluorescence with cryostat sections of rat organs. In our laboratory we have developed a second identification technique for these antibodies: Western-blotting. To compare immunofluorescence and immunoblotting results, we selected sera from 252 patients: 142 sera from patients with documented PBC, 50 from patients with another hepatic disease, 10 from patients with haematological lupus and 50 from healthy blood donors. We characterized antimitochondrial antibody M2 by the presence of one or more of five antigenic determinants: 65-70 kDa (a), 52-54 kDa (b), 44 kDa (c), 23-26 kDa (d) and 16-20 kDa (e). This technique is especially useful as a backup method intention for identifying a very slight or atypical fluorescence pattern.

[Comparison of indirect immunofluorescence on Crithidia luciliae of Farr test, and immunoenzymatic methods for the screening of anti-native DNA autoantibodies]. / Comparaison de l'immunofluorescence indirecte sur Crithidia luciliae du test de Farr, et des méthodes immunoenzymatiques pour le dépistage des autoanticorps anti-ADN natif.

Anti-native DNA (ds DNA) antibodies were measured by the Farr assay, an indirect immunofluorescence on Crithidia luciliae (IIFCL) and a newly commercialised enzyme-linked immunosorbent assay (Elisa) in the sera of 270 patients: 73 negative controls, 67 patients with systemic lupus erythematosus (SLE), 73 with clinical symptoms of another connective tissue disease and 61 patients with liver diseases. The Farr assay remains a reliable method, IIFCL seems to be as specific but less sensitive and Elisa has a higher sensitivity but a lower specificity. Finally, 35 sera from the 270 patients were tested for anti-ds DNA antibodies using two other commercialised Elisa-related techniques. The results suggest little correlation between the three Elisa methods.

[Development of an immunoenzyme assay technique of ELISA type for detecting anti-SSB antibodies. Comparative study of 2 kits]. / Mise au point d'une technique de dosage immuno-enzymatique de type ELISA pour la détection des anticorps anti-SSB. Etude comparative de 2 trousses.

The anti-SSB antibodies were measured using two enzyme immunoassays (ELISA). The difference between the both results from the preparation of the SSB antigenic extract. The first method, developed in our laboratory, uses a purified SSB antigen extracted from calf thymus, while the other uses an antigen cloned by genetic engineering. We have realized an analytic investigation about the repetability, the reproducibility and the detection limit of our ELISA method and we have refined its evaluation in using a clinic study carried out on 203 subjects (55 had a Sjögren syndrome, 47 had a systemic lupus erythematosus, 17 had a rheumatoid arthritis, 13 a progressive systemic sclerosis, 10 a polymyositis and 61 healthy subjects (blood donors)). These measures were worked out in order to compare them with the Ouchterlony method of reference. The results we have obtained are totally similar to the ELISA methods, with a global correlation factor of 0.96 in spite of the difference on the preparation of SSB antigenic extract. The enzyme immunoassay is a lot more sensitive than the Ouchterlony method since, for a Sjögren sample, we obtain a sensitivity of 0.69 while the sensitivity is only of 0.51 for the immunoprecipitation. In the lupus sample, the sensitivity is respectively of 0.42 and 0.25.

[The diagnostic value of anti-DNA antibodies depends on the technic used for their detection]. / La valeur diagnostique des anticorps anti-ADN dépend de la technique utilisée pour leur dépistage.

Three anti-native DNA antibody detecting assays were compared using sera from 948 patients with clinical symptoms of connective tissue disease and 55 definite systemic lupus erythematosus patients. The Farr assay was more effective than the two other assays in the diagnosis of lupus. Anti-DNA antibody detection by ELISA was as sensitive as the Farr assay; in contrast indirect immunofluorescence on Crithidia luciliae had a significantly lower sensitivity, detecting less than one out of two cases of lupus detected. Particularly ELISA but also indirect immunofluorescence may give positive results in the absence of lupus, so that results obtained by each of these assays must be confirmed by the Farr assay if they are used in the diagnosis of lupus. The significance of antibodies detected by one assay but not by the others is discussed.