Multiple serologic reactions and their relationship to clinical activity in systemic lupus erythematosus

Lymphocyte Subsets in a Large Cohort of Patients with Systemic Lupus Erythematosus

In search of markers of disease activity in patients with SLE we have investigated blood lymphocyte subsets from a large cohort of patient. Seventy-one patients were studied using a well-defined panel of fluorescent monoclonal antibodies which recognize the major T, B and NK lymphocyte subsets and activated cells. Flow cytometry was used with standard automated software.

Overall, SLE patients were lymphopenic. The proportion of activated T cells was increased and NK cells were decreased in both proportion and absolute numbers (P < 0.001). This decrease was more pronounced in the more active patients.

None of the T cell activation markers was shown to distinguish different degrees of disease activity. However, the percentage of NK cells was significantly reduced in active disease states (P< 0.01). Decreased numbers of NK cells could potentially reduce the resistance of SLE patients to infectious organisms.

Predictive value of autoantibodies for activity of systemic lupus erythematosus

There is no serologic test that reliably measures disease activity in systemic lupus erythematosus (SLE). The ‘gold standard’ is the anti-dsDNA antibody test, which has been used as a marker of disease activity by clinicians in SLE for over 35 years. Anti-dsDNA antibodies perform best in those with lupus nephritis, specifically in the presence of a proliferative lesion [World Health Organization (WHO) class III or IV] on renal biopsy. In one recent meta-analysis, the mean positivelikelihood ratio of anti-dsDNA antibodies as a marker of disease activity in SLE was 4.14, implying the overall predictive effect was small. More recently autoantibodyassays have been developed that show greater promise in gauging SLE disease activity, specifically anti-nucleosome and anti-C1q antibodies (especially with renal disease activity). Other tests thought previously to be lacking in specificity that refinements in ELISA technology now render possibly useful include anti-heparan sulfate, anti-ssDNA and anti-Scl-70 autoantibodies. Other tests that as yet have not been shown to be as reliable (and therefore are not as useful in clinical practice for serial determinationto measure disease activity) include other anti-extractablenuclear antibodies (anti-Ro, La, Sm, RNP), anti-cardiolipinantibodies, and anti-nuclear cytoplasmic antibodies (ANCA). New technologies using proteomic determinations show promise as aids in the search for more reliable and feasible autoantibody determinations of disease activity in SLE.

Predictors of renal relapse in Korean patients with lupus nephritis who achieved remission six months following induction therapy

Renal relapse in patients with lupus nephritis (LN) is a risk factor for poor renal function. Therefore, there is a need to identify clinical and serological risk factors for renal relapse. A total of 108 patients with LN were enrolled in this study. All the subjects had achieved complete remission or partial remission following six months of induction therapy. We retrospectively analyzed their clinical and laboratory indices, final renal function, and kidney biopsy findings. The median follow-up period after LN diagnosis was 81 months. Renal relapse had occurred in 36 patients; it occurred in 38% and 46% of patients within five and 10 years after achievement of renal remission, respectively. There was no difference between the relapsed rate in patients with complete remission and that in those with partial remission. Clinical variables at LN onset and renal biopsy findings in the patients with sustained remission and relapsed patients were also not different. The probability of renal relapse was significantly higher in patients with an earlier age of onset of systemic lupus erythematosus (SLE) (≤ 28 years versus >28 years; HR 7.308, P = 0.001), seronegativity for anti-Ro antibody (seronegativity versus seropositivity; HR 3.514, P = 0.007), and seropositivity for anti-dsDNA antibody at six months after initiation of induction therapy (HR 8.269, P = 0.001). Our study demonstrated that early onset of SLE, seronegativity for anti-Ro antibody and increased anti-dsDNA antibody following six months of induction therapy independently predict renal relapse among the LN patients.

Thirty years, five hundred patients: some lessons learned from running a lupus clinic

The lupus clinic at University College Hospital has been established since January 1978. It was started by Michael Snaith and has been responsible for the long-term care of over 500 patients. I have been involved with the clinic since July 1979 and in this article offer some thoughts about the complexities of managing systemic lupus erythematosus.

Accuracy of semiquantitative immunoenzymatic methods in quantitation of anti-topoisomerase I (Scl-70) antibodies

Reports of a possible correlation between anti-Scl-70 antibody concentration and clinical manifestations in systemic sclerosis patients have recently appeared in the scientific literature. The goal of our study was to evaluate, by means of a multicenter study, the analytical reliability of immunoassay systems in the quantitative measurement of Scl-70 antibodies. Three blind samples (H, M, L) at different anti-Scl-70 antibody concentrations, and a low concentration antibody serum (LPC) used as a common calibrator, were sent three times in a 6-month time span to 39 Italian clinical laboratories. Each laboratory was asked to calculate dosages following the enzyme-linked immunosorbent assay (ELISA) method they used and report the optical density values of each sample (ODs), of the cutoff serum provided by the manufacturer of the kit used (ODco) and of LPC (ODLPC). The overall analytical imprecision (between methods and between laboratories) of the three different determinations of the values respectively expressed in ODs, ODs/ODco and ODs/ODLPCratio was 47.1, 52.8 and 34.0% for sample H, 56.2, 47.4% and 34% for sample M and 84.6, 86.0 and 86.6% for sample L. The average intra-method analytical imprecision was, respectively, 20.7, 29.8 and 18.6% for sample H, 24.6, 26.5 and 19.3% for sample M, and 30.6, 28.1 and 20.2% for sample L. The commercial ELISA methods currently used to determine the presence of anti-Scl-70 autoantibodies show considerable differences in the quantitative determination. The best results for reproducibility analyses have been obtained when the values were expressed as a ratio between the ODs of the sample and of the common calibrator (ODs/ODLPC). Forward-looking clinical studies that can clarify the usefulness of quantitative determination of anti-Scl-70 antibodies in the monitoring of diffuse scleroderma patients can be performed only when standard serum with a known antibody concentration and calibration curves for quantitative ELISA measurements are made available.

Lack of autoantibody production associated with cytomegalovirus infection

To confirm an association between cytomegalovirus (CMV) infection and the presence of antibodies to Smith (Sm), to ribonucleoprotein (RNP), and to a component of the U1 ribonucleoproteins (U1-70 kD), we measured antibodies to these protein antigens using an enzyme immunoassay and an immunoblot. The antibodies were measured in the sera of 80 healthy subjects, one-half of whom were naturally CMV seropositive and one-half were CMV seronegative, and in eight subjects immunized with a live attenuated strain of CMV. None of the vaccinees developed antibodies to Sm, to RNP, or to U1-70 kD at either 4 or 12 months after immunization. Additionally, there was no statistically significant association between levels of antibodies to Sm or to RNP and between sera obtained from vaccinees, natural CMV seropositive individuals, and CMV seronegative individuals. One CMV seropositive serum and one CMV seronegative serum tested positive for antibodies to U1-70 kD. These data indicate that neither wild-type infection nor the live-attenuated Towne vaccine frequently induce autoantibody production.

Immunological and clinical differences between juvenile and adult onset of systemic lupus erythematosus

INTRODUCTION

Systemic lupus erythematosus (SLE) in children usually follows a more severe course than in adults, but sometimes in the previous studies reported there are many confounding factors.

OBJECTIVE

To analyse the immunological and clinical characteristics of SLE juvenile onset and SLE adult onset.

METHODS

We studied 179 patients with SLE, 49 patients were aged 6-18 yrs at onset of disease. Anti-dsDNA antibodies were detected by radioimmunoassay and antibodies to extractable nuclear antigens (ENA): anti-nRNP, anti-Sm, anti-Ro/SS-A and anti-La/SS-B antibodies by ELISA, counterimmuno-electrophoresis and immunoblotting.

RESULTS

Juvenile-onset SLE shows a higher frequency of cutaneous vasculitis (44.8% vs 27.6%; P < 0.05), seizures (18.3% vs 7.6%; P < 0.05) nephropathy (67.3% vs 48.4%; P < 0.025), and discoid lupus erythematosus (26.5% vs 13.8%; P < 0.05). The incidence of articular manifestations is lower than in adults (85.7% vs 96.1%; P < 0.025). No significant differences were found between the two groups in relation with the prevalence of antinuclear antibodies.

CONCLUSIONS

Juvenile-onset SLE has more frequent neurological and renal manifestations than adult-onset SLE, but immunological markers are similar in both groups. These features suggest the most severe clinical manifestations in the juvenile-onset SLE group are not related with the presence of studied antibodies by different methods.

'Sustained remission' in a case of SLE following megadose cyclophosphamide

Cytotoxic therapy, especially with cyclophosphamide in the dose 8-20 mg/kg used as intermittent pulses, has been shown to improve both patient and renal survival in systematic lupus erythematosus (SLE), but to date there is no cure for the disease. Owing to the paucity of recognisable clones, the rationale and goal of cytotoxic immunosuppressive therapy in the treatment of immune-mediated diseases as against malignancies is to suppress the aberrant inflammation and immune-mediated reactions responsible for tissue damage, without dangerously suppressing the normal host defence mechanism(s). We report the case of a patient suffering from SLE with nephritis who has remained in sustained remission over the past 8 years without any maintenance therapy following an accidental administration of a single dose of 5000 mg of intravenous cyclophosphamide (44.2 mg/kg body weight). The patient recovered fully from pancytopenia following the injection. Presently, she is asymptomatic and working gainfully. Her laboratory parameters including blood counts, urine analysis, FANA and anti-dsDNA have reverted to normal. Cyclophosphamide in the dose of 30-160 mg/kg has been safely and effectively used in various neoplastic conditions with the aim of destroying every possible tumour cell. The experience of the present case suggests that such an approach may be applicable to SLE.

Antiphospholipid antibodies and the antiphospholipid antibody syndrome

The antiphospholipid antibody syndrome is a multiple-system disorder characterized by persistently elevated antiphospholipid antibodies and/or arterial or venous thrombosis, thrombocytopenia, or recurrent spontaneous abortion. Anticardiolipin antibodies and the lupus anticoagulant are different classes of antiphospholipid antibodies associated with this disorder. Cutaneous manifestations are common and may be the presenting sign of the underlying disease. This article reviews the clinical manifestations, laboratory assays, histopathologic features, and treatment of the antiphospholipid antibody syndrome.

Systemic lupus erythematosus: clinical expression and anti-Ro/SS--a response in patients with and without lesions of subacute cutaneous lupus erythematosus

Patients with subacute cutaneous lupus erythematosus (SCLE) have recurrent annular and/or psoriasiphorm skin lesions, with or without systemic disease.

OBJECTIVE

To analyse the clinical expression and the Ro/SS-A response associated with SCLE in patients with systemic lupus erythematosus (SLE).

METHODS

128 consecutive patients with SLE were studied. Anti-Ro/SS-A antibodies were detected by ELISA, (anti-60 kD Ro/SSA antibodies), immunoblotting (anti-60 kD and anti-52 kD Ro/SS-A antibodies) and counterimmunoelectrophoresis (CIE).

RESULTS

Seventeen patients (13.2%) showed SCLE lesions. Photosensitivity was more frequent in patients with SCLE (82%) than in patients without these cutaneous lesions (45%) (OR: 5.6). Arthritis (OR: 6.3), Raynaud's phenomenon (OR: 4.9), pleuritis (OR: 7.6), central nervous system disorder (OR: 6.4), renal disease (OR: 6.3), anemia (OR: 7.9), hypocomplementemia (OR: 6.1) and anti-dsDNA antibodies (OR: 12.7) were significantly more frequent in patients without SCLE. Anti-Ro/SS-A antibodies were detected in 15 (88.2%) patients with SCLE and 62 (55.8%) patients without SCLE by ELISA, in 10 (58.8%) and 34 (30.6%) patients by immunoblotting, and in 13 (76.4%) and 34 (30.6%) by CIE, respectively. Anti-60 kD-Ro/SS-A and anti-La antibodies, but not anti-52 kD-Ro/SS-A, were significantly more frequent in patients with SCLE than in patients without SCLE.

CONCLUSIONS

The presence of SCLE lesions in patients with SLE is associated with a more favourable prognosis. The major anti-Ro/SS-A response is directed against the native 60 kD Ro/SS-A protein.

Prevalence of 13 autoantibodies and of the 16/6 and related pathogenic idiotypes in 465 patients with systemic lupus erythematosus and their relationship with disease activity

With a cross sectional study of 465 consecutive systemic lupus erythematosus (SLE) patients tested for 13 autoantibodies (Aab) and two idiotypes we determined the prevalence of Aab according to disease activity, both general and at particular organ systems. Seventy seven percent of SLE sera had at least one Aab and 56% had it at high titres. Pathogenic idiotypes had a prevalence of less than 10% and 166 sera had Aab to 5 or more antigens and 9 sera had Aab against all 13 antigens tested. Patients with active disease had increased prevalence of Aab to DNP, ssDNA, ENA, mitochondria and histones when considered at 5 s.d. above the mean of normal controls. The higher positivity of Aab in patients with active disease was confirmed in logistic regression analysis adjusted by age, disease duration, and intensity of treatment. A trend was observed of increased prevalence and titres of Aab from inactive disease without treatment, to inactive disease but still being treated, to active disease. Only 22% of patients with active disease had no Aab and the higher the number of Aab the higher the frequency of active disease. Patients with active arthritis, and to a lesser degree those with active mucocutaneous involvement, had higher prevalence and titres of most autoantibodies than patients with disease activity at other organ systems. Active renal disease associated only with anti-dsDNA, whereas active CNS disease associated with anti-mitochondrial Aab. Our findings support the vision of SLE as an immune dysregulation leading to polyclonal B cell activation with resulting production of multiple Aab. Their profiles seem influenced by genetical, hormonal and environmental factors and, in turn, they contribute to the clinical picture in each patient. Disease activity influences the presence of some, but not all, Aab and some of them may remain present in some patients, even in remission.

Bone mineral density and hormonal status in men with systemic lupus erythematosus

A loss in bone mass was reported in premenopausal systemic lupus erythematosus (SLE) women, but this problem has not been studied in SLE males. We evaluated bone mineral density (BMD) in SLE males and the relationship between prolactin (PRL) and testosterone with BMD. We also studied the controversial effect of steroid therapy on BMD in these patients. We measured BMD in the lumbar spine and at the hip in 20 SLE men (mean age 37 y) and in the controls (n = 40). We measured PRL and testosterone in serum and saliva. The mean dose of prednisone at the time of study was 11.6 mg; and cumulative dose was 17.6 g. No significative decrease in BMD was detected in SLE males vs controls; either in the lumbar spine (1.00 +/- 0.1 vs 1.05 +/- 0.1 g/cm2) or in the femoral neck (0.84 +/- 0.1 vs 0.87 +/- 0.1 g/cm2). No patient or control had osteoporosis or fractures. We did not find any relationship between BMD and cumulative dose and baseline dose of corticosteroids. The mean values of PRL and testosterone (serum and salivary) were in the normal range. We did not find any correlation between BMD, PRL and androgens. This study did not show a loss in bone mass in SLE men on corticosteroid therapy.

Analysis of three new idiotypes on human monoclonal autoantibodies

We have identified and characterised three new idiotypes on human IgM McAbs generated from the splenocytes of a SLE patient with active disease. RT-6, which binds H1 and Sm/RNP, expresses essentially a private Id. Its expression is limited to a small number of human McAbs and the sera from patients with infectious diseases. In contrast RT-72Id and RT-84Id, expressed on McAbs which are polyreactive for two or more antigens, have a public distribution. RT-72Id and RT-84Id are found on McAbs from murine and human adult, and foetal tissues. In sera, significant numbers of SLE, RA and patients with other autoimmune diseases are positive for both Ids. RT-84Id is also elevated in SLE relatives and spouses, and in patients with Klebsiella infection. No correlation with disease activity, IgM or IgG levels was observed with either Id. However, RT-72Id was significantly associated with anti-ssDNA antibodies and RhF. RT-6Id and RT-72Id are located on the framework regions of the mu heavy chain, whereas RT-84Id is present on the kappa light chain, within the binding site. The McAbs are encoded by mainly germline genes: heavy chains of RT-6, RT-72 and RT-84 are encoded by the genes VH26, VH4.22 and VH4.21, respectively, and the light chain sequences of RT-6 and RT-72 are derived from DPL11 and HK102. Immunofluorescent staining revealed the presence of RT-72Id and RT-84Id positive immunoglobulin deposits in 18% and 45%, respectively, of the lupus renal sections compared with none in the disease control group, suggesting that these Ids may contribute to the pathology of the disease.

Systemic lupus erythematosus

Assessing patients with SLE is difficult because of the heterogeneity of the disease. The Revised 1982 ARA Classification Criteria set has been widely accepted for classifying SLE patients for inclusion in clinical studies, but it is not appropriate for making the diagnosis of SLE in an individual and is not helpful for classifying patients with early or mild disease in population based epidemiological studies. Further refinement of this criteria set to meet these objectives and to facilitate subdivision of patients with SLE into those with similar clinical, serological or genetic features poses a future challenge for the clinical epidemiologist. A number of valid and reliable indices are available for measuring clinical disease activity in SLE (Table 3). Despite their different approaches they have been shown to correlate well with each other and hence would appear to be measuring the same thing. The exact choice of instrument will be dictated by the purpose for which it is required. Although none is perfect they are useful for monitoring groups of patients in outcome studies in a research setting. Practically, disease activity indices are unlikely to be appropriate for dictating treatment decisions in individual cases: an instrument comprehensive and flexible enough for this purpose would undoubtedly be far too cumbersome for widespread use. Ultimately such fine tuning will continue to rely upon the skill and intuition of experienced physicians.

Loss of bone mineral density in premenopausal women with systemic lupus erythematosus

OBJECTIVE

To evaluate bone mineral density (BMD) in premenopausal patients with systemic lupus erythematosus (SLE).

METHODS

We measured BMD by dual energy x ray absorptiometry at lumbar vertebrae L2-4 and at the right femoral neck in 74 premenopausal white patients (mean age 30.8 years) with SLE who were receiving glucocorticoid therapy, and in a control group.

RESULTS

The mean cumulative dose of prednisone was 32.5 (SD 28) g. The mean dose at the time of absorptiometry was 13.7 (6.9) mg. BMD was significantly reduced at the spine and at the femoral neck in SLE patients when compared with the control group: L2-4 = 0.943 (0.1) g/cm2 v 1.038 (0.1) g/cm2 (p < 0.001); femoral neck = 0.766 (0.09) g/cm2 v 0.864 (0.1) g/cm2 (p < 0.001). Nine patients (12.1%), but none of the control group, had a BMD less than the reference range.

CONCLUSION

BMD in premenopausal patients with SLE was less than that in a control group and less than the reference range of values defining the presence of osteoporosis in 12.1%. We did not find a relationship between BMD and either cumulative or baseline dose of corticosteroid therapy.

Nucleosome-restricted antibodies are detected before anti-dsDNA and/or antihistone antibodies in serum of MRL-Mp lpr/lpr and +/+ mice, and are present in kidney eluates of lupus mice with proteinuria

OBJECTIVE

To compare the humoral response to nucleosomes with the response to their individual components (double-stranded DNA [dsDNA] and histones) and to assess the involvement of antinucleosome antibodies in immune deposits in the kidney of MRL mice.

METHODS

We used enzyme-linked immunosorbent assays of sera and kidney eluates for antibody activity against purified nucleosomes, dsDNA, and histones.

RESULTS

Antinucleosome antibodies emerged before anti-dsDNA and antihistone antibodies. A fraction of antinucleosome antibodies reacted exclusively with nucleosomes and not with their components, dsDNA and histones. These nucleosome-restricted antibodies were detected in the proteinuric MRL mouse kidney eluate.

CONCLUSION

Our findings support the notion that nucleosomes play a major role in the emergence of antinuclear autoantibodies and that antinucleosome antibodies might be involved in the nephritogenic process in murine lupus.

The central role of chromatin in autoimmune responses to histones and DNA in systemic lupus erythematosus

To gain insight into the mechanisms of autoantibody induction, sera from 40 patients with systemic lupus erythematosus (SLE) were tested by ELISAs for antibody binding to denatured individual histones, native histone-histone complexes, histone-DNA subnucleosome complexes, three forms of chromatin, and DNA. Whole chromatin was the most reactive substrate, with 88% of the patients positive. By chi-square analysis, only the presence of anti-(H2A-H2B), anti-[(H2A-H2B)-DNA], and antichromatin were correlated with kidney disease measured by proteinuria > 0.5 g/d. SLE patients could be divided into two groups based on their antibody-binding pattern to the above substrates. Antibodies from about half of the patients reacted with chromatin and the (H2A-H2B)-DNA subnucleosome complex but displayed very low or no reactivity with native DNA or the (H3-H4)2-DNA subnucleosome complex. An additional third of the patients had antibody reactivity to chromatin, as well as to both subnucleosome structures and DNA. Strikingly, all sera that bound to any of the components of chromatin also bound to whole chromatin, and adsorption with chromatin removed 85-100% of reactivity to (H2A-H2B)-DNA, (H3-H4)2-DNA, and native DNA. Individual sera often bound to several different epitopes on chromatin, with some epitopes requiring quaternary protein-DNA interactions. These results are consistent with chromatin being a potent immunogenic stimulus in SLE. Taken together with previous studies, we suggest that antibody activity to the (H2A-H2B)-DNA component signals the initial breakdown of immune tolerance whereas responses to (H3-H4)2-DNA and native DNA reflect subsequent global loss of tolerance to chromatin.

Identification and characterization of a new human DNA reactive monoclonal antibody and a common idiotype, WRI 176 Id beta

We describe a human monoclonal antibody designated WRI 176 beta and a common idiotype that it carries. This antibody was derived from the spleen of a patient with SLE. WRI 176 is an IgM kappa monoclonal reacting with ssDNA, dsDNA, poly(dT) and it is likely that mAb WRI 176 beta is a representative of the so-called natural autoantibodies. The common Id designated WRI 176 Id beta is located on the heavy chain of the mAb WRI 176 beta molecule and appears to be located outside the binding site. Sequence analysis of the WRI 176 beta heavy chain showed it to be highly homologous (97.3%) with a germline gene 56PI derived from a human fetus. In a retrospective analysis, although 44% of SLE patients had raised levels of the WRI 176 beta no correlation was found with the activity of the disease. The idiotype was also expressed frequently in a range of autoimmune rheumatic and infectious diseases and in some healthy first-degree relatives of SLE patients.

Lymphocyte subsets in a large cohort of patients with systemic lupus erythematosus

In search of markers of disease activity in patients with SLE we have investigated blood lymphocyte subsets from a large cohort of patient. Seventy-one patients were studied using a well-defined panel of fluorescent monoclonal antibodies which recognize the major T, B and NK lymphocyte subsets and activated cells. Flow cytometry was used with standard automated software. Overall, SLE patients were lymphopenic. The proportion of activated T cells was increased and NK cells were decreased in both proportion and absolute numbers (P < 0.001). This decrease was more pronounced in the more active patients. None of the T cell activation markers was shown to distinguish different degrees of disease activity. However, the percentage of NK cells was significantly reduced in active disease states (P < 0.01). Decreased numbers of NK cells could potentially reduce the resistance of SLE patients to infectious organisms.

Assessment of lupus: where are we now?

Decisions about treatment for patients with SLE are based on numerous criteria, including the rate of change of clinical features and disease markers (especially antibodies to dsDNA and markers of complement turnover), which organ systems are affected, the severity of manifestations, and the presence of pre-existing damage (which may reduce the reserve capacity of the organ system). Most of the currently available organ systems calculate a single overall score, at a single point in time, and take few of these considerations into account. SLAM is the only index to consider directly the scoring of severity as well as activity, though this concept is probably inherent in most of the other indices because of various methods for weighting the scores. Preliminary studies have indicated that four of the scales (BILAG, SLAM, LAI, and SLEDAI) are sensitive to change. Few of the indices have been tested longitudinally, hence their role in clinical trials remains to be established. None of the indices considers the impact of damage, indeed this is not their remit, but this concept is being considered by an international working group. Outcome in SLE has been shown to be determined by, among other things, the number of exacerbations and the presence of renal or neurological disease. It would seem, therefore, important to measure disease activity in designated organ systems, which most of the indices fail to do. The inclusion of immunological tests in some scales (for example, SIS, SLEDAI, LAI) makes them unsuitable for use as instruments to validate immunological or other scatological markers. Furthermore, given the heterogeneity of disease manifestations in SLE, and evidence linking scatological abnormalities with specific clinical manifestations, it is perhaps naive to expect a new scatological test to correlate strongly with overall disease activity. Three of the currently available activity scales have been shown to be reliable, both between and within raters (BILAG, SLAM, SLEDAI). The lack of a 'gold standard' for measuring disease activity in SLE makes it difficult to be sure that these scales are actually measuring what they are supposed to be measuring (criterion validity), but they do correlate strongly with each other in cross sectional studies, suggesting that they are, at least, all measuring the same thing (convergent validity). Convergent validity for these instruments used longitudinally remains to be established, particularly for patients with very active disease. In conclusion, measurement of disease activity in SLE is central to patient care, and a number of instruments are available fro this purpose. Although none is perfect, most are reliable and valid, and are suitable for classifying and monitoring groups of patients in the research setting. In reality, the indices are used with the additional benefit of laboratory markers and, as yet, no one has found the instruments sufficiently sensitive and specific to rely entirely upon them. The exact choice of instrument should be governed by the purpose for which it is required in clinical practice. Disease activity scales are unlikely to be appropriate for dictating treatment decisions in individual cases. An instrument which would be comprehensive and flexible enough for this purpose would necessarily prove too complicated and cumbersome for widespread use.

Complement split product C3d as an indicator of disease activity in systemic lupus erythematosus

In order to investigate, if complement levels can be used as an indicator of clinical activity in systemic lupus erythematosus (SLE), levels of C3, C4, CH50, and C3d were measured in 79 patients, 41 with inactive, 31 with moderately active and 7 with severely active disease. Our study shows that C3d, and particularly the C3d/C3 ratio, provide sensitive markers for disease activity in SLE. Since C3d is a direct measurement of complement turnover, it reflects complement activation better than C3, C4 and CH50.

Surface expression of heat shock protein 90 by blood mononuclear cells from patients with systemic lupus erythematosus

Previous studies have indicated that blood mononuclear cells from 15-20% of patients with systemic lupus erythematosus (SLE) carry elevated levels of hsp90, a heat shock protein associated with steroid receptors in cells. We analysed surface expression of hsp90 on mononuclear cells (lymphocytes and monocytes) from patients with SLE by monoclonal antibody AC88 and flow cytometry. Whilst all blood mononuclear cells have intracellular hsp90, a significant proportion of patients with SLE expressed hsp90 on lymphocyte and monocyte surfaces. This was significantly higher on SLE lymphocytes than in laboratory controls and was positively correlated with disease activity. Comparison of total hsp90 with surface hsp90 in the same SLE patients' blood mononuclear samples indicated a correlation with a subgroup of patients. There was no correlation with expression of surface hsp90 by lymphocytes and activation markers. Patients with Sjögren's syndrome, rheumatoid arthritis, dermatomyositis and scleroderma were studied as disease controls and increased levels of shsp90 were detected in only three of the 53 patients studied. It is concluded that surface hsp90 expression is a feature of about 20% of patients with SLE and is correlated with high disease activity. The exposure of this hsp on the surface of some lymphocytes suggests that it is a candidate autoantigen in SLE.

Anti-dsDNA and Sm autoantibodies in systemic lupus erythematosus

During the present study the coincidence of anti-dsDNA and Sm antibodies was detected in 16 percent of 51 consecutive SLE patients. These antibodies were detected by the standard indirect immunofluorescence and Ouchterlony tests. All patients with anti-dsDNA and Sm antibodies showed disease activity, including renal, CNS and pulmonary disease. We excluded a cross reactivity of these antibodies by ELISA, using competitive experiments with dsDNA and Sm antigens. The results support the presence of multiple autoantibody production during SLE activity, and suggest that different mechanisms may underlie the induction and regulation of both autoantibodies.

Induction of primary antiphospholipid syndrome in mice by immunization with a human monoclonal anticardiolipin antibody (H-3)

Antiphospholipid syndrome (APLS) is characterized by thrombocytopenia, thromboembolic phenomena, and recurrent fetal loss, associated with anticardiolipin antibodies (ACA) and/or lupus anticoagulant. The syndrome may be primary or may be associated with other conditions such as systemic lupus erythematosus. We have previously shown the ability to induce APLS in naive mice following passive transfer of serum and monoclonal ACAs. Similarly we generated the secondary APLS in BALB/c mice following immunization with a pathogenic anti-DNA antibody. In the current study we report on the induction of primary APLS following immunization of BALB/c mice with a human monoclonal ACA (H-3). The mice developed high persistent titers of ACA. The APLS was characterized by prolonged activated partial thromboplastin time, low fecundity rate (21% vs. 48% of control immunized mice), high resorption index of fetuses (25% vs. 3%), and low weights of embryos and placentae. Our study points to the ability of inducing primary APLS in naive mice. The induction of various presentations of APLS by different ACA may explain the diversity of clinical manifestations seen in patients with APLS.

Psychiatric disorder and cognitive impairment in systemic lupus erythematosus

OBJECTIVES

To determine the point prevalence of psychiatric disorder in patients with systemic lupus erythematosus (SLE). To investigate associations between psychiatric disorder and social stress, cognitive impairment, systemic disease activity, and corticosteroid therapy.

METHODS

A cross-sectional study of 73 consecutive patients with SLE assessed using standardized psychiatric and clinical research methods.

RESULTS

Current psychiatric disorder was present in 15 patients (20.5%) and was significantly associated with social stress, lack of social support, and impairment on 2 tests of cognitive function (Verbal Fluency Test and Benton Visual Retention Test, Part A, number of errors). There was no association with systemic disease activity or corticosteroid therapy. Cognitive impairment on 2 or more tests was found in 26% and was associated with clinical evidence of central nervous system (CNS) disease, but not systemic disease activity or corticosteroid therapy.

CONCLUSIONS

The point prevalence of psychiatric disorder in this cohort of patients with SLE was found to be similar to that observed in patients with rheumatoid arthritis. It was independently associated with social stress and 2 indicators of cognitive impairment, but not with systemic disease activity or corticosteroid therapy. Marked cognitive impairment was present in a significant percentage of patients even when there was no overt evidence of CNS involvement.

A long-term immunological study of childhood onset systemic lupus erythematosus

Immunological dysregulation is an important cause of the development of systemic lupus erythematosus (SLE). Serological evaluation has been useful in the clinical management of patients and as a prognostic indicator. Sixteen patients who developed SLE as children were followed up for more than three years and immunological data collected. The results showed that (a) complement C3 concentration was lower in the active stage of SLE, especially during a major clinical exacerbation, but rarely preceded a major flare up. The concentration was often normal during the mildly to moderately active stage. In contrast, a low complement C4 concentration often preceded a major clinical exacerbation and could be of longer duration, sometimes persisting regardless of disease activity. (b) A T cell subset distribution study showed persistently low CD4 positive T cells in the peripheral blood of patients with SLE during the long term follow up, strongly suggesting that the intrinsic defect is mainly localised in T helper/inducer cells. These abnormal cellular defects did not tend to return to normal even in long term remission. (c) The persistently higher serum interleukin 2 and interleukin 2 receptor concentrations in SLE strongly suggested that the T cells were preactivated in vivo and that these phenomena might persist even in remission. (d) The best single parameter for predicting active SLE was anti-dsDNA. It was highly correlated with disease activity in most patients, and the asymptomatic increase of anti-dsDNA (greater than or equal to 60 U/ml, radioimmunoassay) was often followed by a major clinical exacerbation, especially in patients with a simultaneously low complement C4 concentration, suggesting that it might be an important warning sign of a major flare up. High dose steroids are indicated in this group of patients.

Analysis of antibodies to RNA in patients with systemic lupus erythematosus and other autoimmune rheumatic diseases

The frequency and clinical associations of anti-RNA antibodies measured by ELISA were assessed in 138 patients with systemic lupus erythematosus (SLE). Of the sera from these patients 9.4% had anti-RNA antibodies but no distinguishing features, clinical, serological or immunogenetic, between those with or without these antibodies could be identified. However, investigations of patients with other autoimmune rheumatic diseases did not reveal any anti-RNA positivity, which indicates a marked disease specificity for anti-RNA antibodies in SLE. The initial anti-RNA antibody screen used a soluble yeast extract as test antigen. The positive sera were further tested against a range of RNAs from 10 different types of rat tissue. In essence few differences were observed, suggesting that the anti-RNA response is directed against common, highly conserved epitopes.

Pathogenic anti-DNA idiotype (16/6 Id) in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is regarded as a classical autoimmune disease. Despite this belief, no one has been able to induce the disease in naive animals, neither with DNA nor with anti-DNA antibodies. We report on the induction of SLE in BALB/c mice following immunization with a pathogenic anti-DNA idiotype (16/6 Id) or its anti-Id. We also report on a specific treatment with T suppressor cells specific for the 16/6 Id. The induction of SLE in naive mice with a pathogenic anti-DNA Id suggests an additional mechanism for the diversity of manifestations in this disease.

Quantitative clinical assessment of disease activity in systemic lupus erythematosus: progress report and research agenda

No single test allows an adequate measure of disease activity in multisystem diseases such as systemic lupus erythematosus (SLE). In order to evaluate the spectrum of manifestations of disease activity in SLE, investigators have developed numerous ad hoc scales which have not been tested for their validity or reliability. Three instruments have been extensively studied: the British Isles Lupus Activity Group instrument (BILAG), the SLE Disease Activity Index (SLEDAI), and the Systemic Lupus Activity Measure (SLAM). All three have been demonstrated to have convergent and construct validity when compared to the clinician's judgement. The summation of the number of criteria of the American Rheumatism Association (ARA) SLE criteria has been shown to be an inadequate measure of disease activity. Standardized measures of disease activity for SLE should enhance our ability to compare results from different centers in finer distinctions than dead or alive.

Antinuclear autoantibodies in healthy nonpregnant and pregnant women and their offspring

Antinuclear autoantibodies have previously been detected in sera of healthy women although less frequently than in sera of women with autoimmune disorders. The effect of pregnancy on antinuclear autoantibody production in healthy women is as yet debatable. We present four studies in which, by employing the ELISA method, we evaluated the presence of six antinuclear autoantibodies (anti-ds DNA, anti-ss DNA, anti-poly(I), anti-cardiolipin, anti-Sm, and anti-RNP) in the sera of more than 1,000 healthy pregnant and nonpregnant women, including 196 pairs of matched maternal and cord blood sera. In all four studies healthy pregnant women did not demonstrate significantly higher prevalence rates of various serum antinuclear autoantibodies as compared to healthy non-pregnant women. All detected autoantibodies were of the IgM isotype. In only one infant (born to a healthy seronegative mother) was an autoantibody (IgM anti-ss DNA) detected. This may indicate that in certain circumstances the fetus is capable of self-production of autoantibodies.

Induction of autoreactive B cells allows priming of autoreactive T cells

A novel mechanism for breaking T cell self tolerance is described. B cells induced to make autoantibody by immunization of mice with the non-self protein human cytochrome c can present the self protein mouse cytochrome c to autoreactive T cells in immunogenic form. This mechanism of breaking T cell self tolerance could account for the role of foreign antigens in breaking not only B cell but also T cell self tolerance, leading to sustained autoantibody production in the absence of the foreign antigen.

Relation between antinuclear antibodies and the autoimmune rheumatic diseases and disease type and activity in systemic lupus erythematosus using a variety of cultured cell lines

Antinuclear activity was assessed in serum samples from a series of 40 patients with differing clinical subsets (including renal and neurological disease) of systemic lupus erythematosus (SLE) against a transformed keratinocyte line (SvK14)* and normal human keratinocytes. Paired serum samples were studied during disease activity and inactivity, and the effects of ultraviolet radiation on the availability of nuclear antigens in the cell substrates were assessed. Serum samples from 20 healthy controls and 40 disease controls, comprising 10 patients each with rheumatoid arthritis, Sjögren's syndrome, scleroderma, and myositis, were also studied. The keratinocytes all provided sensitive substrates for the detection of antinuclear antibodies (ANAs), and in normal keratinocytes treated with ultraviolet radiation nuclear antigens were exposed on the cell surface. There was no correlation between ANAs and disease activity or patterns so, apart from assisting diagnosis, the detection of ANAs is of little relevance to predicting disease activity.

Detection of human and murine common idiotypes of DNA antibodies in tissues and sera of patients with autoimmune diseases

The expression in tissue and serum of a panel of murine and human common DNA antibody idiotypes (Ids) (BEG 2, PR 4, F-423, I-402, II-28, IV-228, V-88) has been investigated. The murine V-88 Id was detected in eight out of 10 and the human BEG 2 Id in five out of 10 labial biopsies from patients with Sjögren's syndrome. The murine F-423, I-402 and IV-228 Ids were identified in one out of 10 biopsies. In each case the pattern of staining was similar with staining of the acinar basement membrane and a cell population. Using double-labelling immunohistochemistry this cell population were identified as plasma cells. No staining was seen in four normal labial biopsies. The V-88 Id was detected on the epithelial aspect of the thickened basement membrane in three out of nine renal biopsies from patients with systemic lupus erythematosus (SLE). None of the other Ids (BEG 2, PR4, IV-228, F-423 or I-402) could be detected in renal tissue. None of the Ids were found in skin biopsies from SLE patients. Id V-88 may, like the 16/6 Id to which it is phenotypically related, play a role in the pathogenesis of renal lesions in SLE. The BEG 2 Id could be detected in the serum of patients with rheumatoid arthritis (RA) and active untreated tuberculosis. Ids II-28, V-88 and I-402 were elevated in serum from patients with Sjögren's syndrome and II-28 Id in serum from patients with myositis and RA. None of the Ids were elevated in serum from patients with SLE. Apart from the BEG 2 Id, none of the Ids were elevated in serum from patients with tuberculosis or Gram-negative infections. The presence of murine Ids in human tissue and serum suggests that they are cross-species idiotypes and have been conserved through evolution.

Immunology and clinical importance of antiphospholipid antibodies

Having reviewed the literature on the association of aPL antibodies with clinical manifestations, it is clear that this group of autoantibodies are of considerable importance. The presence of aPL antibodies in some but not all individuals confers a risk of a clinical syndrome characterized by recurrent arterial or venous thrombosis, thrombocytopenia, hemolytic anemia, or positive Coombs' test, and in females, recurrent idiopathic fetal loss. In SLE, the risk is approximately 40%, compared with a risk of 15% in the absence of aPL antibodies. However, only one half of persons possessing these antibodies have SLE, and overall the risk is around 30%. In some circumstances, such as in chlorpromazine or infection-associated aPL antibodies, there appears to be no increased risk. At the other end of the spectrum are seen patients whose only clinical manifestations comprise features of this clinical syndrome, and this entity has been designated the primary antiphospholipid syndrome (PAPS). aPL antibodies are also important because they are not uncommon. They have been found frequently in women with idiopathic recurrent fetal loss (30%), in non-autoimmune patients with ischemic heart disease (20%), or venous thrombosis (up to 30%), or stroke (4-47%), and in chronic immune thrombocytopenia (30%). These autoantibodies can be detected using sensitive solid-phase immunoassays employing the CL antigen, or in appropriate coagulation tests to detect LA activity. These assays are simple to perform but require care in selection of the best test and in interpretation of results. Current tests do not distinguish between those persons at risk of the clinical events and those not at risk. Detection of specific isotypes (especially IgG) and antibody level may aid in such a designation. Treatment of aPL antibody-associated syndromes remains a controversial subject. Since thromboses are associated with significant morbidity and potential mortality, there is a good argument for long-term preventive antithrombotic therapy, at least for as long as the antibodies are detectable, in those patients in whom clinical complications have previously occurred. It is not generally recommended that this treatment be offered to individuals in whom aPL antibodies are detected but who have not suffered previous thromboses, since the risk of such events does not appear to be equal within a group of aPL antibody-positive persons. This particularly applies to pregnant women, since live births and uncomplicated pregnancies are observed regularly in the presence of aPL antibodies without specific treatment. A previous history of at least one unexplained, late fetal loss is considered a prerequisite before intervention in subsequent pregnancies.(ABSTRACT TRUNCATED AT 400 WORDS)

Assessment of common idiotype PR4-Id in serial bleeds from lupus patients

Marked fluctuations in the levels of a common DNA-antibody idiotype, PR4-Id have been found on IgM and IgA antibodies in particular and to a lesser extent on IgG in serial bleeds of 14 lupus patients. Few clear cut examples were found of the PR4-Id levels reflecting disease activity. However, the idiotype expression was not simply related to total immunoglobulin levels and the controlling mechanisms of idiotype expression on different isotypes remain a matter of conjecture.

Lupus anticoagulants in systemic lupus erythematosus: prevalence and clinical associations

The prevalence of lupus anticoagulant (LAC) and its relation with reported clinical associations has been determined in 55 patients with systemic lupus erythematosus (SLE) from northern India who were studied prospectively. Kaolin clotting time was used to screen for LAC, which was detected in seven (13%) of the patients. Significant associations were found between LAC and thrombotic events, onset of disease at an early age, and disease of shorter duration. No statistically significant association could be found between LAC and recurrent abortions, pulmonary hypertension, thrombocytopenia, and neurological manifestations. It is concluded that LAC is a useful marker for a subset of patients with SLE at risk of thromboembolic events.

Assessment of the effect of oral corticosteroids on bone mineral density in systemic lupus erythematosus: a preliminary study with dual energy x ray absorptiometry

Dual energy x ray absorptiometry and a wide range of blood and urine tests were used to assess the propensity of patients with systemic lupus erythematosus to develop an impairment of bone mineral density. Surprisingly, in this preliminary study no significant differences in bone mineral density were found when patients taking 10 mg or more of prednisolone for six months or longer were compared with those who had never taken prednisolone.

DNA-binding antibodies and parasitic diseases

DNA-binding antibodies are produced during the course of many parasitic infections, including malaria, leprosy and schistosomiasis. These antibodies are also present in certain autoimmune diseases, such as systemic lupus erythematosus, and much information is available about their properties and contribution to related disease processes Here, Anne Wozencraft and Norman Staines consider how DNA-binding antibodies might arise during parasitic infection and discuss how an increased knowledge of their properties and functions could lead to a greater understanding of mechanisms of immuno-pathology in these diseases.

Comparison of DNA antibody idiotypes in human sera: an international collaborative study of 19 idiotypes from 11 different laboratories

The distribution of and relationships between 18 anti-DNA antibody idiotypes and one anti-acetylcholine receptor antibody idiotype have been tested in an international collaborative study of human sera from 180 individuals. The main finding is that the serum levels of many of these idiotypes, whether of murine or human origin, show a high degree of statistical correlation. The studies in a wide range of autoimmune rheumatic diseases confirm that none of the idiotypes tested is disease specific, but 13 of 15 (87%) whose levels were recorded as OD units or cpm correlated strongly with anti-ssDNA antibody levels and 11 of 15 (73%) with total serum IgM. Expression of several idiotypes was found to fluctuate in parallel with disease activity in SLE; levels of others were also elevated in the healthy relatives of lupus patients whilst a few were also raised in the spouses of these patients. The data support the notion that there may be only a few groups of related DNA antibody idiotypes. The correlations between the idiotypes with regard to their quantities, association with disease activity, and wide distribution in different diseases and healthy individuals suggest at least two explanations. First, all of these idiotypes may be present in normal immunoglobulin repertoires and simply increase in response to poly- or oligoclonal B-cell activation in autoimmune diseases. Secondly, these idiotypes may be structurally linked to each other, so that their behaviour under conditions of specific antigenic stimulation is similar. Genetic and structural studies will be required to distinguish between these possibilities.

Correlation between clinical features of systemic lupus erythematosus and levels of antihistone antibodies of the IgG, IgA, and IgM isotypes

An attempt was made to define the correlation between the clinical features of systemic lupus erythematosus and levels of circulating antihistone antibodies of the IgG, IgA, and IgM isotypes. Serum antibody levels were determined by enzyme linked immunosorbent assay (ELISA) on serial blood samples (n = 4) from 25 patients, representing five subgroups: (a) renal disease; (b) central nervous system disorders; (c) skin and joint disease only; (d) serositis; and (e) deep venous thrombosis with or without spontaneous abortion. The levels of antihistone antibodies of each isotype varied widely from patient to patient, but antibody levels in the four samples from each patient correlated closely. A close correlation between levels of IgG and IgA antihistone antibodies was found but there was no correlation between these isotypes and IgM antihistone antibodies. In individual patients no simple correlation between disease activity and antihistone antibody levels was established, but levels of antihistone antibodies of the IgG and IgA isotypes were significantly higher in those patients in whom the disease was consistently more active.

Measurement of increases in anti-double-stranded DNA antibody levels as a predictor of disease exacerbation in systemic lupus erythematosus. A long-term, prospective study

To evaluate the predictive power of changes in levels of antibodies to double-stranded DNA (anti-dsDNA) as a predictor of disease exacerbations in systemic lupus erythematosus (SLE), we performed a prospective study on 72 unselected patients with SLE (mean duration of study 18.5 months, range 6-35 months). Patients were seen at least once every 3 months, and disease activity was scored according to a specific protocol. Plasma samples were obtained at least once every month and were assessed for anti-dsDNA antibody (by the Crithidia luciliae assay, an enzyme-linked immunosorbent assay [ELISA], and the Farr assay) and for complement components C3 and C4. Twenty-seven of 33 disease exacerbations observed during the study period were accompanied by a positive test result for anti-dsDNA antibody (27 by the Farr assay, 19 by the C luciliae assay, and 23 by the ELISA). Twenty-four of these exacerbations were preceded by a significant increase in anti-dsDNA antibody levels (23 by the Farr assay, 12 by the C luciliae assay, and 17 by the ELISA). The first observance of a significant increase in anti-dsDNA antibody levels preceded the exacerbation by 8-10 weeks. Significant increases in anti-dsDNA antibody levels not followed by an exacerbation were observed in 5 cases by the Farr assay, in 7 cases by the C luciliae assay, and in 3 cases by the ELISA; however, in 3 cases, 2 cases, and 1 case, respectively, these increases were followed by an increase in disease activity that did not fulfill the criteria for an exacerbation. Serial measurement of anti-dsDNA antibody levels was more sensitive for predicting exacerbations than was measurement of C3 and/or C4 levels (P less than 0.03). Serial assessment of anti-dsDNA antibody levels, especially by the Farr assay, is a sensitive and reasonably specific method for predicting disease exacerbations in SLE.

Cross-reactivity distinguishes serum and nephritogenic anti-DNA antibodies in human lupus from their natural counterparts in normal serum

To distinguish the properties of anti-DNA antibodies in patients with lupus from those in normal individuals, we compared the ligand binding, idiotypic and charge properties of serum anti-DNA antibodies derived from: patients with active lupus; normal individuals; and among Ig eluted from the kidneys of two patients with active lupus nephritis (one with mesangial proliferation and the other with membranous nephropathy). The kidney eluate anti-DNA antibodies were the most cross-reactive; they cross-reacted with ssDNA, poly(GdC), poly(dT), poly(dG), poly(dC), ZDNA, SmRNP and the phospholipids cardiolipin and phosphatidyl serine. Lupus serum anti-DNA antibody cross-reacted with polynucleotides but not with phospholipids, whereas anti-DNA antibodies derived from normal serum reacted only with poly(dT). An anti-idiotype (anti-IdD; produced against serum anti-DNA antibodies from one patient) reacted with: anti-DNA antibodies in 8/9 lupus sera; antibodies in both kidney eluates; and anti-DNA antibodies from 5/7 normal sera. Anti-IdD did not react with Ig that did not bind to DNA. Isoelectric focusing of Ig showed that the charge of anti-DNA antibodies from lupus serum and normal serum were similar and unrestricted (pI 5.4-9.0); Ig in kidney eluates varied: membranous lupus pI 4.5-8.6; mesangial lupus pI 8.1-9.1. We conclude that idiotypically related anti-DNA antibodies in tissue lesions, lupus serum and normal serum from different individuals can be distinguished on the basis of their cross-reactive antigen-binding properties. Furthermore the cross-reactive properties of lupus auto-antibodies may influence their capacity to form glomerular immune deposits.

Enhanced binding of lupus sera to the polyamine-induced left-handed Z-DNA form of polynucleotides

The natural polyamines putrescine, spermidine, and spermine are small polyvalent cations present in all living cells. Spermidine and spermine are excellent promoters of left-handed Z-DNA, an immunogenic form of DNA that binds readily with anti-DNA antibodies in the sera of patients with systemic lupus erythematosus (SLE). We studied the binding of a panel of 16 SLE sera to poly(dA-dC).poly(dG-dT) and poly(dG-m5dC).poly(dG-m5dC) in the presence and absence of spermidine and spermine using an enzyme-linked immunosorbent assay. The majority of SLE sera showed a 50-150% mean increase in optical density values when incubated with the polynucleotides and either 0.25 mM spermidine or 0.025 mM spermine than when incubated with the polynucleotides alone. Under these conditions, the polynucleotides assumed the Z-DNA form. Since polyamines are ubiquitous cellular components and since potential Z-DNA-forming alternating purine-pyrimidine sequences are widely dispersed in native DNA, the increased binding of SLE sera to polyamine-induced Z-DNA suggests a pathogenic role for these compounds in SLE.

DNA antibody idiotypes: an analysis of their clinical connections and origins

Approximately thirty common DNA antibody idiotypes have been described on hybridoma derived or affinity purified DNA-binding antibodies. There are associations between some idiotypes and the clinical manifestations of systemic lupus erythematosus although none are sufficiently firm to be clinically useful in identifying subsets of SLE or in assessing disease activity in individual patients. The expression of these idiotypes is not confined to DNA antibodies in SLE. They may be found in the serum from patients with a range of autoimmune rheumatic disorders, infectious disease and blood dyscrasias. In most cases the antigen binding specificity of the antibody bearing the idiotype is unknown. The precise relationship between the various idiotypes is becoming better understood with increasing availability of genetic and structural data. DNA antibody idiotype manipulation may provide a potential new therapeutic modality in SLE.

Binding of antibodies to the extractable nuclear antigens SS-A/Ro and SS-B/La is induced on the surface of human keratinocytes by ultraviolet light (UVL): implications for the pathogenesis of photosensitive cutaneous lupus

Autoantibodies to the non-histone nucleoprotein antigens SS-A/Ro, SS-B/La, and RNP are highly associated with photosensitive cutaneous lupus erythematosus (LE). In order to better understand the potential mechanisms of ultraviolet (UV) light on photosensitivity in patients with cutaneous LE, we designed immunopathologic in vitro and in vivo experiments to evaluate the effects of UV on the binding of such autoantibodies to the surface of human keratinocytes, one major target of immunologic damage in photosensitive LE. Short-term 2% paraformaldehyde fixation of suspensions of cultured human keratinocytes previously incubated with monospecific antiserum probes enabled the detection of ENA expression on the cell surface by flow-cytometry analysis. UVB light (280-320 nm) induced the binding of monospecific antibody probes for SS-A/Ro and SS-B/La on keratinocytes in a dose-dependent pattern with maximal induction observed at the dose of 200 mJ/cm2 UVB. Binding of SS-A/Ro, SS-B/La, and RNP antibody was augmented strongly, but binding of anti-Sm was very weak. In contrast, UVA (320-400 nm) light had no effect on the induction of binding of these antibody probes. Identical results were seen by standard immunofluorescence techniques. Hydroxyurea-treated keratinocytes showed similar induction of those antigens by UVB irradiation, which suggested that ENA expression on cultured keratinocytes by UVB were cell-cycle independent. Tunicamycin, an inhibitor of glycosylation of proteins, reduced UVB light effect on the SS-A/Ro and SS-B/La antigen's expression. These in vitro FACS analyses revealed that ENA augmentation on the keratinocyte cell surface was dose dependent, UVB dependent, glycosylation dependent, and cell-cycle independent. In vivo ENA augmentation on the keratinocyte surface was examined in suction blister epidermal roofs. Specific antibody probes for SS-A/Ro, SS-B/La, RNP, and Sm bound to human keratinocytes in intact suction blister epidermis following UVL irradiation in vivo. Using three different protocols, we have demonstrated that antibodies to SS-A/Ro, SS-B/La, and U1RNP bind to UVL-irradiated human keratinocytes. We speculate that this antibody binding is an important inducer of antibody dependent keratinocyte damage in photosensitive cutaneous lupus.