Clinical value of measuring soluble interleukin-2 receptor in polymyalgia rheumatica.

Serum levels of soluble interleukin-2 receptor (sIL-2R) were measured in 15 patients with polymyalgia rheumatica (PMR) and followed prospectively for 11.5 months (range 2-22) and also in 22 patients with PMR treated with corticosteroids for a mean period of 47 months. The controls consisted of 21 patients in the same age range as the PMR patients, admitted to the hospital for various diseases, and of 40 healthy younger subjects. The initial sIL-2R values in the patients with newly diagnosed, untreated PMR were significantly higher than the values seen in the same patients after corticosteroid treatment for a median of 6 months and in PMR patients on corticosteroid treatment for more than a year (p < 0.005 and p < 0.05, respectively). However, while being significantly higher than the values in the normal controls, the sIL-2R values in PMR did not differ from the values seen in the hospital controls. Thus, this assay seems to be of little clinical value in the management of patients with PMR.

Antikeratin antibodies: diagnostic and prognostic markers for early rheumatoid arthritis.

Antibodies to the stratum corneum of rat oesophagus (antikeratin antibodies) were assayed by indirect immunofluorescence in a prospective study of patients with early rheumatoid arthritis (RA). At the beginning of the study, antikeratin antibodies of IgG class were detected in serum samples from 27/71 (38%) patients compared with 1/20 (5%) control patients with reactive arthritis, and 1/38 (3%) healthy blood donors. At the end of the two year follow up, 27/67 (40%) patients with RA were positive for antikeratin antibodies. The patients with RA who were initially positive for antikeratin antibodies had a more active disease course than the patients negative for antikeratin antibodies as measured by clinical, laboratory, and radiological variables. The prevalence of positivity for antikeratin antibodies fluctuated during the follow up, the variation paralleling the disease activity. The occurrence of HLA-DR4 was similar in patients with RA who were positive and negative for antikeratin antibodies. Antikeratin antibodies were also found in seronegative patients with RA, confirming that antikeratin antibodies do not have rheumatoid factor activity. These results show that antikeratin antibodies are detectable at the time of the initial diagnosis of RA and that the positivity for antikeratin antibodies may have prognostic significance in early RA.

Outcome of systemic lupus erythematosus. A study of 66 patients over 7 years with special reference to the predictive value of anti-DNA antibody determinations.

A cohort of 66 patients with SLE that were thoroughly studied, both clinically and serologically in 1980-81, when they had a mean disease duration of eight years, were evaluated seven years later in order to assess the long-range outcome of the disease. Five patients were lost from follow-up and 12 (20%) died during the follow-up. The estimated 10-year survival was 91%. A total of 30 patients (45%), showed no signs of nephritis at any stage, and in only eight an active nephritis was found during the follow-up. The previous antibody determinations, provided no predictive information regarding the behaviour of the renal manifestations. Arthralgia was the main clinical symptom during the follow-up. Hypertension developed in 23%. At the end of the follow-up the disease was regarded as active in 13% of the patients.

Antibodies to Sm and SS-A demonstrated by enzyme immunoassay. Correlation to clinical manifestations and disease activity in patients with systemic lupus erythematosus.

Using commercially available antigens, enzyme-linked immunosorbent assays (ELISAs) were set up to demonstrate antibodies of IgG class against Sm and SS-A. Anti-Sm antibodies were demonstrated in 40% of patients with systemic lupus erythematosus (SLE), in 12% of patients with SJögren's syndrome, in 6% of patients with rheumatoid arthritis (RA) and in 12% of patients with miscellaneous rheumatic disorders. Anti-SS-A antibodies were seen in 63% of the SLE patients, in 37% of the patients with Sjögren's syndrome and in 23% of the patients with RA. In the patients with SLE, high levels of anti-Sm antibodies were related to the presence of Raynaud's phenomenon, whereas patients with a malar rash tended to have high levels of anti-SS-A antibodies. In 17 SLE patients followed over a period of time a correlation was seen between the levels of the anti-Sm antibodies and the disease activity. We concluded that it is useful to include ELISAs for the demonstration of anti-Sm and anti-SS-A antibodies in determining the serological profile and in the follow-up of patients with SLE.

A subset of systemic lupus erythematosus with progressive cystic bone lesions.

Clinical and serological findings of 16 patients with systemic lupus erythematosus (SLE) who had progressive cystic bone lesions were compared with a control group of 19 patients with SLE without radiological evidence of bone cysts. Central nervous system manifestations, synovitis, and other radiologically observed skeletal abnormalities were more prevalent in the patients with cysts than in the control group. Higher concentrations of C reactive protein, and a greater incidence of rheumatoid factor positivity were seen in the patients with cysts than in the control patients, but no other serological differences were found. It is suggested that patients with SLE with progressive cystic lesions form a subgroup of the syndrome characterised by an increased acute phase reaction.

Autoantibody activity of cryoglobulins and sera in systemic lupus erythematosus. Association of IgM class rheumatoid factors with Raynaud's syndrome.

A total of 218 samples obtained during a follow-up study of 36 patients with systemic lupus erythematosus (SLE) were tested for the presence of cryoglobulins. Cold-insoluble precipitates were found in 81% for the patients (29 patients, 114 samples). The protein concentration of the cryoglobulins correlated significantly with the disease activity. Autoantibody activity was determined in the dissolved cryoglobulins and in corresponding serum samples by enzyme-linked immunosorbent assays (ELISA). IgM-RF could be demonstrated more often in the cryoglobulins than in the sera (75% vs. 14%), whereas IgA-RF were seen in 28% of both cryoglobulins and sera. Anti-ssDNA and anti-poly(A) antibodies of both IgG and IgM classes were found more often in the sera than in the corresponding cryoprecipitates. In 7 samples from 5 patients an increase in the IgG-anti-ssDNA activity was seen after DNase digestion of the cryoglobulins. Patients with Raynaud's syndrome had a significantly higher level of cryoprecipitating IgM class rheumatoid factors than other patients. There was also an association between the IgG-anti-poly(A) antibody levels in the cryoglobulins and the activity of the disease. There was no difference with regard to the composition of the cryoglobulins, between patients with nephritis and those without an overt renal disease. Thus, the presence of cryoglobulins in SLE indicates active disease, but not necessarily renal involvement. IgM rheumatoid factors may play a role in the pathogenesis of Raynaud's syndrome of SLE patients.

Screening test for rheumatic diseases: a combined enzyme immunoassay of rheumatoid factors and antibodies to DNA and extractable nuclear antigens.

Three hundred and one sera from patients with rheumatic and other diseases were investigated using a simple enzyme immunoassay for screening of rheumatoid factors and antinuclear antibodies. The assay had a sensitivity of 77% for systemic lupus erythematosus, 90% for the primary sicca syndrome, and 89% for rheumatoid arthritis. Only 13% of sera from patients with chronic non-rheumatic diseases were positive. The test was further evaluated in a group of patients with suspected rheumatic disease who were followed up for six to 12 months. The test was positive in 16 of 17 sera from patients with connective tissue diseases but in only seven of 36 sera (19%) from patients with non-inflammatory joint diseases. None of the four patients with reactive arthritis was positive by this test. The sensitivity of the assay was comparable with that of the agglutination and immunofluorescence tests for rheumatoid factors and antinuclear factors. For the screening of rheumatoid factor and antinuclear antibodies this kind of test panel offers a simple alternative to the conventional tests for small clinical laboratories and for those in which the autoantibody tests could be automated, as the assay can be performed in one working day and only one dilution of serum is needed to obtain a quantitative result.

Yersinia arthritis, immune functions and histocompatibility antigens.

Secondary immune response to tetanus toxoid (TT), monocyte function, and generation of suppressor cells were studied in patients with previous yersinia arthritis (YA) and healthy controls. A comparison of HLA-B27 positive and negative subjects revealed that leukocytes from the former showed significantly higher responses to TT but not to a variety of other antigens in a lymphocyte proliferation test, and higher rates of migration in a leukocyte migration inhibition assay in the absence of TT. The enhanced migration of leukocytes supports the concept that hyper-reactive neutrophils contribute to inflammatory symptoms in HLA-B27 positive subjects, irrespective of previous YA. No correlation was found between HLA-DR specificities and YA. However, HLA-DR2/HLA-B7 was associated with high suppressor cell activity and low serum levels of anti-TT-antibodies. This accords with the view that HLA-DR antigens play a role in the regulation of immune response.

Anti-DNA antibodies of IgA class in patients with systemic lupus erythematosus.

Sera obtained from 53 patients with systemic lupus erythematosus (SLE) were investigated for the presence of immunoglobulin class-specific antibodies against native (ds)DNA and denatured (ss)DNA. The methods employed were the Crithidia luciliae test and an enzyme-linked immunosorbent assay (ELISA), respectively. Anti-dsDNA antibodies of IgG class were seen in 42%, IgM-anti-dsDNA antibodies in 43%, and IgA-anti-dsDNA antibodies in 30% of the patients. There was an association between the presence of both IgG- and IgA anti-dsDNA antibodies and the activity of the disease. Patients with active nephritis also had anti-dsDNA antibodies of IgG and IgA class significantly more often than patients with inactive nephritis or without renal disease. IgG-anti-ssDNA antibodies were seen in 89%, IgM-anti-ssDNA antibodies in 51%, and IgA-anti-ssDNA antibodies in 66% of the patients. Patients with nephritis had low levels of antibodies to ssDNA of IgM class. We suggest that immunoglobulin class-specific anti-DNA antibodies should be determined in the diagnosis and monitoring of SLE.

Profiles of antibodies to histones, DNA and IgG in patients with systemic rheumatic diseases determined by ELISA.

The occurrence of antibodies against the total histone complex and the histone fraction H1, antibodies against denatured (ss) DNA and the synthetic double stranded polynucleotide poly dAT, as well as rheumatoid factors (RF) was determined in patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS) using enzyme linked immunosorbent assays (ELISA). Antihistone antibodies could be demonstrated at a frequency of about 17% in the patients with systemic rheumatic disease with no differences between the groups, even if there was a tendency for anti-H1 antibodies to occur more often in the SLE and SS patients than in the RA patients. Some of the antihistone antibody activity seen in the RA patients seems to be due to crossreactive RF. All patient groups showed significant IgG anti-ssDNA antibody activity compared to the controls, but the highest antibody levels were seen in the SLE patients. IgG antipoly dAT antibodies occurred significantly more often and at higher levels in the SLE patients than in the other patient groups. Although the individual tests did not readily distinguish the 3 diseases from each other, the antibody profiles were different. Patients with SS had the broadest reactivity, and the SLE patients had antibodies predominantly restricted to polynucleotides.

Assessment of class-specific antibodies against denatured DNA in patients with systemic lupus erythematosus.

In this retrospective study 103 serum samples from 16 females with systemic lupus erythematosus (SLE), obtained during a mean follow-up time of 2 years, were investigated for the presence of anti-denatured [single-stranded (ss)] DNA antibodies of the IgG, IgM, and IgA classes. The anti-ssDNA antibodies were determined by an enzyme-linked immunosorbent assay (ELISA), and the results were expressed in three ways: as units derived from a single serum dilution and as two parameters, E and A, calculated from the dose-response curve, E being an estimate of the effective amount of antibodies and A a function of the reaction constant between the antigen and the antibody. The simultaneous occurrence of anti-ssDNA antibodies of all three immunoglobulin classes was seen most often in the patients with the shortest duration of the disease. Clinically active disease was found to correlate with high reaction constants of the IgA anti-ssDNA antibodies. There was also an association between the IgA anti-ssDNA antibody levels and the presence of nephritis. Great fluctuations in the amounts of effective antibodies of the IgG class were seen in seven patients, in six of whom changes in the disease activity also were seen. Changes in the disease activity were unaccompanied by fluctuations in the IgG anti-ssDNA levels in four patients; two of these patients were positive for antibodies against extractable nuclear antigens.(ABSTRACT TRUNCATED AT 250 WORDS)

Follow-up of antibodies against single-stranded DNA in patients with haematological malignancies.

Antibodies against single-stranded DNA (ssDNA) were followed by enzyme-linked immunosorbent assay in weekly serum samples of 39 patients with acute myeloid leukaemia (AML), 11 with acute lymphatic leukaemia (ALL) and 26 with other haematological malignancies. Their frequency and mean level during the entire follow-up were higher than in sera of healthy blood donors. Patients with AML had the highest levels and prevalence of anti-ssDNA antibodies, i.e. overall frequencies of IgG class antibodies in patients with AML, ALL and other haematological malignancies were 97%, 82% and 58%, respectively. Antibodies of IgM class were less frequently found. Prevalence and levels of anti-ssDNA antibodies were already at least as high in newly diagnosed malignancies as later during the course of the disease. Following bacterial septicaemias, these antibodies were significantly low. No consistent correlations between levels of anti-Candida antibodies formed in response to fungal infections or concentrations of serum immunoglobulins and anti-ssDNA antibodies were found.

Anti-DNA antibodies: the choice of assays for routine diagnostic work.

Sixty-six sera from 23 patients with systemic lupus erythematosus (SLE), 26 sera from patients with rheumatoid arthritis (RA), and 22 sera from normal healthy subjects were tested for the presence of antibodies against native (ds) DNA by the Crithidia luciliae immunofluorescence test and by the Farr assay, and for the presence of antibodies against denaturated (ss) DNA by the enzyme-linked immunosorbent assay (ELISA). Anti-dsDNA antibodies were detected in 57% of the SLE patients by the Crithidia test and in 65% by the Farr assay. Two of the RA sera were positive in the Crithidia test, whereas all were Farr negative. Anti-ssDNA antibodies of IgG class could be detected in 74% of the SLE patients and in none of the RA sera, while anti-ssDNA antibodies of IgM class were found in 26% of the SLE patients and in one RA serum. There was a good correlation between the results of the Farr assay and the IgG-anti-ssDNA ELISA but no agreement was found between the results of the Farr assay and the Crithidia test. We also measured the amount of C-reactive protein (CRP) in the sera but no correlation was seen between the levels of CRP and anti-DNA antibodies. We conclude that the demonstration of anti-ssDNA antibodies of IgG class is a good screening method in the diagnosis of SLE, and that antibodies against native DNA should be determined, preferably both by the Crithidia test and the Farr assay to confirm the diagnosis and in the follow-up of the patients.

Demonstration of anti-keratin antibodies by ELISA using keratin or thiol-containing compounds in urea as antigens.

During the development of an enzyme-linked immunosorbent assay (ELISA) for the demonstration of anti-keratin antibodies (AKA) it was observed that rabbit anti-keratin antisera also reacted with polystyrene surfaces treated with beta-mercaptoethanol in 8 M urea (ME-urea). Sera from non-immunized rabbits or rabbits immunized with antigens unrelated to keratin failed to react. The specificity of the reaction was further assessed by absorption experiments and by testing affinity-purified AKA. IgM activity against ME-urea could be demonstrated in 62.5% of sera from patients with infectious mononucleosis and in 37.5% of sera from patients with rheumatoid arthritis, and there was a good correlation to the presence of AKA. Coating of the solid phase with compounds containing free SH groups in 4-8 M urea generated the antigen of this ELISA. The exact molecular configuration of this presumptive synthetic antigen is obscure, but the ME-urea ELISA seems to provide a simple way to detect anti-keratin antibodies of a certain specificity.

The usability of the MRL/1 mouse strain in detection of anti-rheumatic drugs.

D-Penicillamine (5 mg/kg), prednisolone (0.5 mg/kg), tolfenamic acid and thiabendazole (10 mg/kg) were chronically administered to male and female mice of MRL/1 strain. The treatment was started either at 4 weeks of age (prophylactic dosing) or at 12 weeks of age (therapeutic dosing) and continued until the termination at 24 weeks of age. In male mice all the drugs caused a significant retardation in IgM-RF formation with one of the dosing regimes. D-Penicillamine and prednisolone also had an inhibitory effect on lymph node enlargement. In female mice, however, only thiabendazole retarded the RF activity significantly. None of the drugs had any marked effect on anti-ssDNA antibody formation, and none of the treatments affected the development of renal disease or modified the survival of these mice.