Clinical utility of common serum rheumatologic tests

Serum rheumatologic tests are generally most useful for confirming a clinically suspected diagnosis. Testing for rheumatoid factor is appropriate when rheumatoid arthritis, Sj?gren's syndrome or cryoglobulinemia is suspected. Antinuclear antibody testing is highly sensitive for systemic lupus erythematosus and drug-induced lupus. Anti-double-stranded DNA antibodies correlate with lupus nephritis; the titer often corresponds with disease activity in systemic lupus erythematosus. Testing for anti-Ro (anti-SS-A) or anti-La (anti-SS-B) may help confirm the diagnosis of Sj?gren's syndrome or systemic lupus erythematosus; these antibodies are associated with the extraglandular manifestations of Sj?gren's syndrome. Cytoplasmic antineutrophil cytoplasmic antibody testing is highly sensitive and specific for Wegener's granulomatosis. Human leukocyte antigen-B27 is frequently present in ankylosing spondylitis and Reiter's syndrome, but the background presence of this antibody in white populations limits the value of testing. An elevated erythrocyte sedimentation rate (ESR) is a diagnostic criterion for polymyalgia rheumatica and temporal arteritis; however, specificity is quite low. ESR values tend to correlate with disease activity in rheumatoid arthritis and may be useful for monitoring therapeutic response.     

Importance of detection of SS-A/Ro autoantibody in screening immunofluorescence tests for autoantibodies to nuclear antigens

SS-A/Ro autoantibodies are related to Sj?gren's syndrome and to several clinical subsets of lupus erythematosus. The most widely used laboratory procedure for ANA screening is the indirect immunofluorescence test (IF-ANA); the laboratory detection of anti-SS-A/Ro requires implementation and adherence to several technical and quality assurance recommendations. Using appropriate substrate cells containing the SS-A/Ro antigen, many so-called "ANA-negative" lupus erythematosus patients will demonstrate a positive IF-ANA.     

Comparison of different methods for the detection of autoantibodies in autoimmune diseases

Summary Different immunological techniques were compared for their sensitivity in detecting some important autoantibodies in the sera of patients with rheumatic diseases. Sera of patients with systemic lupus erythematosus were screened for anti-dsDNA, Sm, and RNP autoantibodies byCrithidia luciliae assay, Farr assay, enzyme immunoassay, and immunoblotting. Sera of patients with Sj?gren's syndrome were screened for anti-SSA and anti-SSB antibodies by enzyme immunoassay, counter immunoelectrophoresis, and immunoblotting and sera of patients with scleroderma for SCL-70 autoantibodies by enzyme immunoassay counter immunoelectrophoresis, and immunofluorescence on Hep-2 cells. Enzyme immunoassay and counter immunoelectrophoresis gave the most positive results and the best agreement compared with the other techniques. Immunofluorescence gave few positive results for each antibody evaluated. Immunoblotting gave intermediate results for all autoantibodies except anti-SSA, where the prevalence was low. There was no relationship between levels of dsDNA, Sm, and RNP antibodies and disease activity score in systemic lupus erythematosus patients.     

The clinico-immunological subtypes of systemic lupus erythematosus]

Based on clinico-immunologic studies subtypes of systemic lupus erythematosus (SLE) were distinguished. The ANF-R++H-DNA-CH50 variant determines acute onset of SLE with renal injury in the form of diffuse glomerulonephritis. The ANF-Sp-RNP-RF mirrors the development of Raynaud's syndrome, Sj?gren's syndrome, polymyositis, pneumosclerosis and myocarditis. The ANF-Sp-Ro-RF variant is associated with skin derangement in the form of discoid foci, anular, papulosquamous eruption, vitiligo, hyperpigmentation, and cerebrovasculitis. The Ro-anti-Po, La-anti-La system is related to the idea of SLE, seronegative in accordance with ANF, when rat liver sections are used as a substrate in immunofluorescence.     

Cerebral manifestation in a case of Sj?gren's syndrome (author's transl)]

A case of Sj?gren's disease is described in which isolated cerebellar symptoms were prominent. Serological investigations gave no evidence of disseminated immune vasculitis, systemic lupus erythematosus or any other autoimmune disease. The cerebrospinal fluid protein changes, which were diagnostic of an autoimmune process in the CNS and suggestive of Sj?gren's syndrome are discussed.     

Serum collagenase-like peptidase activity in rheumatoid arthritis and systemic lupus erythematosus

Collagenase-like (CL) peptidase activity in serum, which was measured using a newly synthesized substrate, (succinyl-Gly-Pro-Leu-Gly-Pro)-4-methylcoumaryl-7-amide, was significantly lower in patients with advanced rheumatoid arthritis or with systemic lupus erythematosus than that in normal controls. Decrease of the serum enzyme activity was more pronounced in systemic lupus erythematosus. No significant change in serum CL-peptidase activity was found in other connective tissue diseases such as mixed connective tissue disease and Sj?gren's syndrome.     

Dermatoglyphic investigations in respect to the genetic basis of autoimmune diseases (author's transl)]

Dermatoglyphics of patients with systemic lupus erythematosus, scleroderma and Sj?gren's syndrome were very different from the striking findings in Hashimoto's thyroiditis established in 1971 (Weninger and coworkers). Hence, it was concluded that the characteristic dermatoglyphic pattern of Hashimoto's thyroiditis is specific for this autoimmune disease, but not the expression of a general genetic predisposition to autoimmunity.     

ANA-negative, anti-Ro-antibody positive subacute cutaneous lupus erythematosus

A female patient presented with the typical clinical and histological features of disseminated lupus erythematosus (LE). Direct immunofluorescence, as well as antinuclear antibodies were negative, but antibodies directed against the cytoplasmic Ro-antigen were found. The Ro-antigen is regarded as highly specific for SLE and Sj?gren's syndrome. Clinical features and diagnosis of this distinct LE subset ("ANA negative, anti-Ro-positive LE"), as well as the sensitivity and specificity of the substrate in ANA determinations are discussed.     

Antibodies to centromere antigens measured by an automated enzyme immunoassay

BACKGROUND: Anticentromere antibodies (ACA) are frequently observed in patients with Raynaud's phenomenon and in the CREST syndrome, a subclass of systemic sclerosis. Likewise, ACA are also found in other autoimmune and non-autoimmune diseases. The objective of the present study was to evaluate the clinical utility of the measurement of antibodies to the best characterized centromere antigen (CENP-B) protein by an enzyme-linked immunosorbent assay (ELISA) that uses human recombinant CENP-B antigen and compare it with indirect immunofluorescence assay (IFA) on HEp-2 cells. METHODS: We have analyzed 128 sera samples from patients with the following diseases: systemic lupus erythematosus (SLE, n = 53), mixed connective tissue disease (n = 1), primary Sj?gren syndrome (n = 10), primary Raynaud's phenomenon (n = 10), primary systemic sclerosis (n = 7), polymyositis/dermatomyositis (n = 3), rheumatoid arthritis (n = 9), cutaneous lupus (n = 5), primary biliary cirrhosis (n = 9), chronic autoimmune hepatitis (n = 5) and ANA-positive non-autoimmune diseases (n = 16). RESULTS: The ELISA evaluated shows a good concordance with IFA, with the advantage of being an automatable quantitative technique. CONCLUSIONS: Measurement of anticentromere antibodies by this ELISA using human recombinant antigen is a useful alternative for the autoimmune laboratory checking for diseases associated with anticentromere antibodies.     

Serum level of interferon-gamma in autoimmune diseases.

Interferon-gamma is one of the cytokines which have various immunoregulatory functions. In the present study, the serum interferon-gamma level was determined in autoimmune diseases. It was increased in the active cases of systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD). Since there was a positive correlation between the serum interferon-gamma level and the rate of peripheral mononuclear cells positive for HLA-DR antigen in systemic lupus erythematosus, circulating interferon-gamma might have a biological functions as suggested by many in vitro studies. In rheumatoid arthritis and Sj?gren's syndrome, there was no correlation between the serum interferon-gamma level and the clinical findings. These data suggest that interferon-gamma might be associated with the pathogenesis of autoimmune diseases such as SLE and MCTD, and it can be one of the indices for their disease activity.     

Defining a novel 75-kDa phosphoprotein associated with SS-A/Ro and identification of distinct human autoantibodies

Mothers of children with neonatal lupus erythematosus (NLE) and heart block, as well as patients with Sj?gren's syndrome (SS) and systemic lupus erythematosus, have serum autoantibodies that recognize SS-A/Ro autoantigens including the 60-kDa ribonucleoprotein. By yeast 2-hybrid screening, we identified a novel 75-kDa protein (pp75) that interacts with the carboxyl 70% of 60-kDa SS-A/Ro. The specificity of interaction was confirmed using mammalian 2-hybrid and chemical crosslinking studies. Immunoprecipitation with radiolabeled HeLa cell extracts showed that pp75 was phosphorylated and associated with 2 other phosphoproteins of 64 kDa. In Northern blot analysis, pp75 was expressed in all tissues analyzed; the highest expression was in the human heart. Based on immunofluorescence of transfected HeLa cells, pp75 is localized predominantly in the cytoplasm, an observation confirmed by immunohistochemistry in untransfected cells. Based on Western blot and ELISA assays, sera from 14 of 84 mothers of children with NLE recognized pp75, including 1 mother in whom anti-SS-A/Ro antibodies were not detected. In addition, sera from 5 of 80 patients with SS were positive for anti-pp75 antibody. Identification of molecular partners is a first step toward elucidating the functions and possible involvement in pathogenesis of long-recognized autoantigens such as 60-kDa SS-A/Ro, which are at present poorly understood.     

Clinico-immunological characteristics of systemic lupus erythematosus with Raynaud and Sj?gren's syndromes (report I)

Forty-one patients suffering from chronic systemic lupus erythematosus with Raynaud and Sj?gren's syndromes and 18 patients with an acute and subacute disease course were examined. It was established that chronic SLE was marked by a high frequency of antibodies to ribonucleoprotein, an increase in the concentration of IgA, the presence of rheumatoid factor. Although the decrease in the concentration of C3c and C4 components of complement was more demonstrable in patients with an acute or subacute course of SLE, the rate of demonstration of circulating immune complexes in the patients' groups under comparison was approximately the same. Involvement of immune complexes in the development of the pathological process in different versions of SLE is discussed.     

Pulse therapy in the complex treatment of severe forms of Sj?gren's syndrome and disease

Ten patients with Sj?gren's disease and 5 patients with systemic lupus erythematosus combined with Sj?gren's syndrome received therapy with high doses of 6-methylprednisolone (pulse-therapy) and cyclophosphamide. Improvement of the stomatological signs of the disease was noted in all the patients: salivation increased, the parotid glands considerably decreased in size, parotiditis recurrences were absent or seldom, and the number of the functioning salivary glands of the lower lip increased. The above therapy showed a positive effect on ophthalmological symptoms of the disease in 5 patients. Combination therapy (6-MP and CP) was effective for the management of such systemic symptoms of SD and SS as arthritis, lymphadenopathy, hepatosplenomegaly, exudative polyserositis, polyneuritis, ulcerative-necrotic vasculitis, cerebrovasculitis, cryoglobulinemic purpura and glomerulonephritis. A significant decrease in the levels of immunoglobulins especially IgA, A-nDNA, cryoglobulins, titers of rheumatoid factors, circulating immune complexes and an increase in the complement were noted in response to therapy.     

Characterization of a distinct nuclear acidic protein antigen (MA) and clinical findings in systemic lupus erythematosus patients with MA antibodies.

Circulating antibodies against certain nuclear acidic protein antigens have been shown to have diagnostic and prognostic importance in connective tissue disease. We describe a new precipitin system found in the sera of patients with systemic lupus erythematosus. The antigen, called MA, was prepared from calf thymus nuclei, and was shown to be distinct from other nuclear acidic protein antigens by physicochemical and immunologic techniques. MA antibodies were detected in the serum of 12 of 66 lupus patients and in none of 554 sera from normal controls or patients with other rheumatic diseases. Lupus patients having MA antibodies had more severe disease than did lupus patients with Sm or native DNA antibodies, manifested by recalcitrant skin rashes and a significantly greater incidence of hypocomplementemia, serious renal disease, hypertension, hepatosplenomegaly, lymphadenopathy, and neurological disease (P values range from 0.025 to 0.005). The presence of circulating MA antigen was demonstrated in three lupus patients immediately before a flare of nephritis. These data suggest that MA is a nuclear acidic protein antigen that may identify a subset of lupus patients with very severe disease. The presence of the antigen in the circulation before clinical flares suggests a possible biologic role for the MA system in an immune complex nephritis.     

Paraproteins in rheumatoid arthritis and related disorders.

There is evidence that the prevalence of monoclonal parparoteinaemia is slightly increased in patients with rheumatoid arthritis. The possibility that this may be a marker of the development of later malignancy in such patients is explored. Mortality rates in rheumatoid arthritis are increased although the development of lymphoreticular malignancy contributes only a small percentage of this increase. However, it does seem likely that patients with longstanding severe rheumatoid arthritis are more at risk of developing myeloma or lymphoma if they have a monoclonal paraprotein band in their serum. IgA paraprotein seems to carry a higher risk than IgG whilst other factors such as urinary free light chains and the presence of secondary Sj?gren's syndrome are of less prognostic significance. Similarly a monoclonal paraprotein may identify patients with primary Sj?gren's syndrome who have a particular risk of later lymphoma whilst this risk does not appear to extend to patients with systemic lupus erythematosus. Patients with an overlap syndrome do not appear to be at greater risk than those with "pure disease". The association of other rheumatological disease and paraproteinaemia is briefly discussed.     

Antinuclear, anticentromere and anti-ScL-70 antibodies in rheumatic diseases]

Methods are described that are used for the titration of antinuclear, anticentromere, and anti-Scl-70 antibodies in systemic scleroderma, systemic lupus erythematosus, and rheumatoid arthritis: indirect immunofluorescence with various antigenic substrates (sections of fresh-frozen rat liver and Hep-2 cell culture), counter-current immunoelectrophoresis, isolation of Scl-70 antigen. Use of Hep-2 cells as a substrate for indirect immunofluorescence was found clinically and diagnostically more effective since it permitted the detection of anticentromere antibodies and anti-Scl-70. Nucleolar, mottled, homogeneous, marginal immunofluorescence types were observed when rat liver sections and Hep-2 cells were used for substrates. Anticentromere antibodies and anti-Scl-70 were isolated significantly more frequently in systemic lupus erythematosus or rheumatoid arthritis.     

Paraproteins in rheumatoid arthritis and related disorders

Summary There is evidence that the prevalence of monoclonal parparoteinaemia is slightly increased in patients with rheumatoid arthritis. The possibility that this may be a marker of the development of later malignancy in such patients is explored. Mortality rates in rheumatoid arthritis are increased although the development of lymphoreticular malignancy contributes only a small percentage of this increase. However, it does seem likely that patients with longstanding severe rheumatoid arthritis are more at risk of developing myeloma or lymphoma if they have a monoclonal paraprotein band in their serum. IgA paraprotein seems to carry a higher risk than IgG whilst other factors such as urinary free light chains and the presence of secondary Sj?gren's syndrome are of less prognostic significance. Similarly a monoclonal para-protein may identify patients with primary Sj?gren's syndrome who have a particular risk of later lymphoma whilst this risk does not appear to extend to patients with systemic lupus erythematosus. Patients with an overlap syndrome do not appear to be at greater risk than those with “pure disease”. The association of other rheumatological disease and paraproteinaemia is briefly discussed.     

T and B Lymphocytes in Peripheral Blood and Tissue Lesions in Sjögren''s Syndrome

Lymphocyte heterogeneity was studied in peripheral blood and salivary gland lesions in 24 patients with Sj?gren's syndrome. Peripheral blood B cells, measured by immunofluorescence with specific antiserum to immunoglobulins or by rosette assay with complementcoated erythrocytes, were increased in most patients. Peripheral blood T cells, measured by immunofluorescence with rabbit antiserum to human thymocytes or by rosette assay with sheep erythrocytes, were reduced in eight patients. Three had associated rheumatoid arthritis, two had a generalized lymphoproliferative disorder, and one each had scleroderma, systemic lupus erythematosus, and neuropathy.The salivary gland lymphocytic infiltrates present in labial biopsy specimens were compared in 10 patients using an indirect immunofluorescent method with anti-human T cell serum and a quantitative focus-scoring method. In general, there was a correlation between the number of T cells and the extent of the infiltrate. Striking accumulations of T cells were present in some patients, but clusters of presumed B cells were also seen. These results indicate an increase in peripheral blood B cells in most patients, a decrease in T cells in some, and a mixed T and B cell infiltrate in the salivary gland lesions.     

Subacute cutaneous lupus erythematosus: clinical aspects, immunology and therapy

Subacute cutaneous lupus erythematosus (SCLE) is a distinct subset of cutaneous lupus erythematosus which is defined by clinical and immunological characteristics. With regard to clinical expression and prognosis, SCLE assumes an intermediate position within the spectrum of LE between purely cutaneous discoid and systemic lupus erythematosus. The main clinical characteristics of SCLE are extensive papulosquamous or anular lesions and photosensitivity. The disease is frequently associated with Sj?gren's syndrome and systemic symptoms, mainly arthralgia. Renal involvement is, however, rare. Circulating Ro-antibodies represent the main autoimmune phenomenon. An immunogenetic disposition to develop SCLE is evidenced by the detection of the HLA-B8, DR3-phenotype in a large proportion of patients. Drug therapy comprises primarily glucocorticosteroids and antimalarials, but retinoids have recently also proved highly effective.     

Immunoassay with fluorescein-labelled antigens--device of a method and its clinical application.

A simple, sensitive, highly reproducible method for assay of antibodies using fluorescein-labelled antigens according to the method by Farr is described. We measured titers of anti-BSA antibodies and antigen binding capacity of sera in BSA immunized rabbits by fluorometric assay with fluorescein isothiocyanate (FITC) labelled BSA, and obtained highly reproducible and quantitative results. The resultd times more sensitive than the results from single radial immunodiffusion. FITC-labelled double or single stranded calf thymus DNA was incubated with sera of patients with systemic lupus erythematosus and New Zealand Black mice. Both anti-double and single stranded DNA antibodies were detected in sera of systemic lupus erythematosus, but only anti-single stranded DNA antibodies in sera of New Zealand Black mice.