Fine specificity of the Ro/SSA autoantibody response in relation to serological and clinical findings in 96 patients with self-reported cutaneous symptoms induced by the sun

Anti-Ro/SSA assays assist the clinician in distinguishing autoimmune diseases such as Sj?gren? syndrome (SS), systemic lupus erythematosus (SLE) and subacute cutaneous lupus erythematosus (SCLE). The objective of the study was to investigate the fine specificity of the autoantibodies in relation to clinical presentation as well as environmental and endogenous factors such as photosensitivity, smoking and immunoglobulin (Ig) levels in patients with Ro/SSA autoantibodies. Serum samples from 96 anti-Ro/SSA positive photosensitive patients were tested for autoantibody levels by enzyme-linked immunosorbent assay (ELISA) using purified recombinant Ro52 kd, Ro60 kd and La proteins as antigens. The highest levels of anti-Ro52 and anti-La were observed in patients with primary SS, and the lowest levels of anti-Ro52 in chronic cutaneous lupus erythematosus (CCLE). SCLE patients with systemic disease (SLE and/or SS) showed higher levels of anti-Ro52 than SCLE limited to the skin. A correlation between high serum levels of IgG and anti-Ro52 (P < 0.01) and between IgA and anti-Ro52 (P < 0.05) and anti-Ro60 (P < 0.05) was found. Polymorphic light eruption (PLE) was common in all diagnostic groups but did not correlate with autoantibody levels. Smoking was more common in lupus patients than in SS patients. Our findings thus propose different mechanisms for different clinical presentations of Ro/SSA positive patients. The testing of anti-Ro52 antibodies might serve as a prognostic tool in photosensitive cutaneous diseases.     

DNA skin tests in patients with definite or suspected systemic lupus erythematosus and in dermatological control patients. A long-term follow-up study

This study presents a long-term clinical and immunological follow-up of 62 patients during 1971 and 1973, tested intradermally with DNA derived from calf thymus. The DNA skin test is positive in almost all clear-cut cases of SLE. In addition, the DNA skin test was positive in 16 patients, but the criteria for SLE were not met at the time of testing. During the follow-up, 7 out of these 16 patients developed definite SLE, 2 developed subacute cutaneous LE and 3 developed ANA-negative SLE. This suggests that a positive DNA skin test may precede the development of SLE or some of its subtypes. All our SLE patients with skin test reactivity presented cutaneous disease manifestations suggesting that similar pathogenetic mechanisms may be involved in DNA tests and natural SLE skin lesions. Because the positive DNA skin test showed correlation with ANA, anti-DNA antibodies, cryoglobulins, lupus anticoagulant and depressed C3 and C4 values, humoral factors may be partly responsible. However, DNA skin test reactivity was also positive in ANA-negative SLE, suggesting that other mechanisms may also be involved.     

Ro/SSA and La/SSB specific IgA autoantibodies in serum of patients with Sjögren's syndrome and systemic lupus erythematosus

OBJECTIVE: To investigate the occurrence of IgA autoantibodies to Ro 52 kDa, Ro 60 kDa and La antigen in serum of patients with primary Sj?gren's syndrome (pSS) and systemic lupus erythematosus (SLE). METHODS: Recombinant Ro 52 kDa, Ro 60 kDa and La antigens were used to analyse autoantibodies in serum from 25 patients with pSS, 30 patients with SLE and 20 controls using a semiquantitative immunoblotting approach. RESULTS: Among the patients with pSS, 21 (84%) had detectable IgA autoantibodies to Ro 52 kDa, 13 (52%) to Ro 60 kDa and 20 (80%) to La antigen. The corresponding results for the patients with SLE were 22 (73%), 14 (47%) and 20 (67%), respectively. No IgA autoantibodies against the three antigens were detected in 20 normal controls. A comparison of several clinical features with the titres of IgA antibodies to Ro 52 kDa, Ro 60 kDa and La, revealed a significant relation between IgA anti-Ro 52 and IgA anti-La to sicca (p< 0.05). Semiquantitative data suggest that IgG is the dominating antibody to the three antigens followed by IgM > IgA in both SLE and pSS patients. Specificity studies of IgA autoantibodies with different subfragments of Ro 52 kDa and Ro 60 kDa antigens showed that IgA antibodies did not differ from IgG and IgM in their recognition pattern. CONCLUSION: These results suggest that besides IgM and IgG, IgA autoantibodies are also detected at high frequency in patients with pSS and SLE. Further studies are necessary to evaluate the contribution of these IgA autoantibodies to inflammation as well as their diagnostic value.     

HLA antigens in Italian patients with systemic lupus erythematosus: evidence for the association of DQw2 with the autoantibody response to extractable nuclear antigens

In order to verify the hypothesis that Italian patients with systemic lupus erythematosus (SLE) may be immunogenetically distinct from SLE patients born in other regions, we investigated the HLA class I and II antigens and their relation with the various autoantibodies characteristic of the disease in an Italian SLE population. Forty-four SLE patients were typed for HLA-A, -B, -C, -DR and -DQ antigens; sera from the same patients were tested for the presence of antibodies to the nuclear or cytoplasmic antigens Ro/SSA, La/SSB, Sm and RNP (ENA). Results of HLA typing showed that the frequencies of DR3 and DQw2 were increased in patients compared with controls. Analysis of the correlations between HLA antigens and anti-ENA antibodies showed that both DQw2 and DR3 were increased in patients with anti-Ro and/or antiLa antibodies, while in patients with anti-Sm and/or antiRNP antibodies the DQw2 and DR4 were found to be increased. Only DQw2 was found to be significantly increased in anti-ENA positive patients. These results might suggest that Italian patients with SLE are, at least in part, different from lupus patients living in other geographical areas and suggest the association of DQw2 with the autoantibody response to ENA in SLE.     

Anti-SSA/Ro and anti-SSB/La antibodies. What's new?

Anti-SSA/Ro and anti-SSB/La autoantibodies recognize different epitopes on polypeptides associated with small RNAs called scYRNA situated mostly in the cytoplasmic compartment (70%) and few in the nuclear compartment (30%). These hYRNPs (h=human) can be found on the cytoplasmic membrane or in small blebs during apoptosis after various stimuli such as UVB, 17-beta-estradiol, viral infection, TNF alpha and other cellular apoptosis inducing molecules. At least two major different proteins are called SSA/Ro: a 52 kDa Ro (with two subtypes alpha and beta) and a 60 kDa Ro. There is only one SSB/La protein of 48 kDa. In some circumstances, other proteins such as calreticuline (MW 57 kDa) join Ro/SSA proteins on some YRNAs. Anti-SSA/Ro antibodies are detected in the sera of 30% of patients with SLE, even during preclinical setting; anti-Ro/SSA are strongly associated (90%) with some subtypes of SLE such as old-onset (>50 y) SLE, subacute lupus erythematosus, drug-induced subacute lupus erythematosus and in patients with hereditary C2 or C4 or C1q deficiency with lupus or lupus-like disease. Anti-SSA/Ro are also associated with primary Sj?gren syndrome (50% to 60%) and with undifferenciated connective tissue disease (UCTD). Anti-SSA/Ro antibodies are almost always present in sera of mothers with babies with neonatal lupus syndrome (NNL) and with complete congenital heart block (CCHB). This last event is very unusual in pregnant patients with anti-Ro/SSA antibodies (1% to 2% of primigeste women). Some good evidences such as experimental models in vitro or ex-vivo, argue for the responsibility of maternal anti-Ro/SSA 52 kDa and/or anti-La/SSB antibodies (or associated IgG antibodies) as major etiologic factor of CCHB and NNL. IgG anti-Ro 52 beta kDa has been shown able to interrupt the atrioventricular conduction as well as the L calcium channel influx of fetal cardiocytes. Other factors must be taken into account to explain discordant twins (with and without CCHB). More recently anti-Ro/SSA antibodies were associated with QT interval prolongation in newborns without CCHB.     

HLA-DR antigens in systemic lupus erythematosus: association with specificity of autoantibody responses to nuclear antigens.

HLA-DR antigens and autoantibodies to the nuclear or cytoplasmic antigens Ro/SSA, La/SSB, Sm, and RNP were determined in North American and Austrian patients with systemic lupus erythematosus (SLE). Analysis of the association of antibodies to these ribonucleic acid (RNA)-protein antigens with HLA-DR antigens showed that HLA-DR3 was related to the presence of anti-Ro/SSA or anti-La/SSB, or both. In contrast, anti-Sm or anti-RNP, or both were associated with HLA-DR4. HLA-DR5 was associated with absence of these autoantibodies. The data extend evidence for the complexity and heterogeneity of SLE. Moreover, they indicate that, in SLE, genes linked to those coding for HLA-DR antigens, are related to the specificity of autoantibody responses rather than to the primary immunological abnormalities of this disorder.     

ANA-negative systemic lupus erythematosus.

The presence of antinuclear antibodies (ANA) in serum is generally considered a decisive diagnostic sign of systemic lupus erythematosus (SLE). Ten patients with clinical signs of disease but persistent negative tests for ANA are examined in this study. Hair fall, Raynaud's phenomenon and recurrent oral ulcers were common in the ANA-negative group. ANA-negative SLE seems to be a subgroup of SLE that has not previously been given adequate attention.     

THE MOLECULAR BASIS OF THE SSA/Ro ANTIGENS AND THE CLINICAL SIGNIFICANCE OF THEIR AUTOANTIBODIES

The SSA/Ro antigens are nuclear and cytoplasmic polypeptideswhich serve as autoantigens in systemic lupus erythemato-sus(SLE) and Sjögren's syndrome (SS). They contain two majorisoforms of 60 and 52 kD. The former is the native antigen whilethe latter is a major autoantigen in its denatured form. A thirdprotein of 46 kD termed ‘calreticulin-Ro’ is anautoantigen found in the sera of some patients with SLE. However,it is probably unrelated to the SSA/Ro system. The clinicalrelevance of anti SSA/Ro antibodies in rheumatic diseases hasalso been considered. Initially these antibodies were thoughtto be an epiphenomenon of autoimmune diseases. Recent studieshave shown that they are associated with specific clinical manifestationsand disease subsets. Furthermore, animal models have demonstratedthat they may enhance tissue damage. It seems that anti-SSA/Roantibodies may play a role in the pathogenicity of SLE and SS. KEY WORDS: SSA/Ro antigen, Autoantibodies, Systemic lupus erythematosus, Sjögren's syndrome     

Serial analysis of Ro/SSA and La/SSB antibody levels and correlation with clinical disease activity in patients with systemic lupus erythematosus

OBJECTIVE: To investigate the temporal correlation between anti-Ro/SSA and anti-La/SSB antibody levels and compare them with variation in clinical disease activity in patients with systemic lupus erythematosus (SLE). METHODS: Sequential serum samples collected over 18-44 months from 18 anti-Ro/SSA positive patients with systemic lupus erythematosus were analysed by ELISA with recombinant Ro60, Ro52 and La antigens. Disease activity was assessed by the BILAG index. RESULTS: Limited antibody level variation over time was found in most patients, but a subset displayed more changes and a co-variation between the levels of separate specificities was found in 40% of patients. In two patients antibody levels fluctuated with the global score. Antibodies also correlated with separate organ/systems involvement in individual patients. CONCLUSION: The Ro60, Ro52 and La antibody profile is fixed at an early stage of disease and in most patients hardly changes. Patients with fluctuating levels tend to have a co-ordinated expression of these autoantibodies.     

ANTI La(SSB) IDENTIFIES A DISTINCTIVE SUBGROUP OF SYSTEMIC LUPUS ERYTHEMATOSUS

The relevance of antibodies for La(SSB) as a marker of a distinctivesystemic lupus erythematosus (SLE) subset was studied in 185lupus patients. Anti La was detected in 39 (21%) and was accompaniedinvariably by anti Ro. Clinically, anti La-positive patientswere distinguished by a later age of disease onset, and a lowfrequency of lupus nephritis. In common with other anti Ro-positivepatients they showed a high frequency of keratoconjunctivitissicca. Anti La identified patients with higher titres of antiRo antibodies and was significantly associated with HLA-DR3.Serological markers such as these are useful for identifyingmore homogeneous populations of SLE patients for studies ofaetiology and pathogenesis. KEY WORDS: SLE, anti La(SSB), anti Ro(SSA), Elderly lupus     

Antibodies to Ro and La

Precipitating antibodies to Ro and La occur in a subset of patients with systemic lupus erythematosus (SLE) constituting just under 50 and 20% respectively of the total spectrum. These precipitating autoantibodies are even more prevalent in primary Sj?gren's syndrome (SS) occurring in 60-80% (anti-Ro) and 40-60% (anti-La) of that disease. Patients with an overlap of SLE and SS virtually all possess both anti-Ro and anti-La. These autoantibodies appear years before the appearance of clinical disease as evidenced by the behavior of women who possess them and herald this presence by having children born with the manifestations of neonatal lupus, principally a characteristic lupus dermatitis or complete congenital heart block. The close association of several clinical manifestations involving the skin, lung, and blood elements suggests a pathogenic role for these autoantibodies in disease expression. The elucidation of these relationships should greatly improve our understanding of the etiopathogenesis of both SLE and SS.     

Hla—dr antigens and anticardiolipin antibodies in northern italian systemic lupus erythematosus patients

Eighty systemic lupus erythematosus (SLE) patients attending 3 clinical centers were evaluated immunologically and immunogenetically. No HLA class I1 antigens were found to be significantly associated with SLE in these patients. A highly significant (P = 6.17 × 1o⁻⁷) association was observed between anticardiolipin antibodies and DR7. A lesser association (P < 0.025) was also observed between DR2 and/or DR3 and anti—Ro (SS-A) antibodies. No relationship was found between any DR antigen and anti-Sm/RNP, antidouble-stranded DNA, or anti—La (SS-B) antibodies.     

Antibodies to cellular antigens in Greek patients with autoimmune rheumatic diseases: anti-Ro(SSA) antibody a possible marker of penicillamine-D intolerance.

One hundred and twenty-four sera from Greek patients with autoimmune rheumatic diseases (29 with systemic lupus erythematosus (SLE), 24 with scleroderma, 11 with primary Sjögren's syndrome (SS), and 60 with rheumatoid arthritis (RA) were tested for antibodies to nRNP, Sm, Scl-70, Ro(SSA), and La(SSB) cellular antigens. The incidence of these antibodies in the different groups of patients examined, did not differ overall from that described previously. It was noted, however, that antibodies to Sm were very infrequently found in Greek patients with SLE and anti-Ro positive patients with SLE did not have the clinical manifestations described by other workers. Finally, it was found that anti-Ro positive patients with RA experienced a high frequency of side effects from penicillamine-D. The significance of these findings is discussed.     

PREVALENCE AND CLINICAL SIGNIFICANCE OF ANTIBODIES TO RIBONUCLEOPROTEINS IN SYSTEMIC LUPUS ERYTHEMATOSUS IN MALAYSIA

One hundred and seventy patients with systemic lupus erytbematosus(SLE) were studied for the prevalence of antibodies to the smallRNA-associated proteins Ro/SSA, La/SSB, Sm, UIRNP and Sm. Therelationship of these autoantibodies to different races, sexesand clinical manifestations of SLE was evaluated. Passive immunodiffusionwas employed using human spleen extract as antigen source forRo and rabbit thymus extract for La, Sm and UIRNP. We foundthe prevalence of antibodies to be as follows: anti-Ro/SSA,36%; anti-La/SSB, 8%; anti-Sm, 15%; anti-UIRNP, 21%. Exceptfor a low prevalence of anti-La, the prevalence of these antibodieswas similar to that in Western studies. The prevalence of anti-Ro/SSAis similar to that reported in the Western studies, but lowerthan that reported in other Oriental patients from Singaporeand Hong Kong. Linkages of anti-Ro with anti-La antibodies wereusual; however, although anti-Sm antibodies were usually associatedwith anti-UIRNP, they were more frequently associated with anti-Roantibodies. The Malay patients had a high prevalence of anti-UIRNPcompared to other races. No gender difference was detected.Anti-Sm antibody was associated with scrositis and anti-UIRNPantibodies with Raynaud's phenomenon. No association was foundbetween the presence of skin, renal or cerebral manifestationsand any specific antibodies or combination of antibodies. KEY WORDS: Systemic lupus erythematosus, Racial comparison, Ro/SSA, La/SSB, Sm, UIRNP     

Autoreactive IgG memory antibodies in patients with systemic lupus erythematosus arise from nonreactive and polyreactive precursors

Persistent autoantibody production in patients with systemic lupus erythematosus (SLE) suggests the existence of autoreactive humoral memory, but the frequency of self-reactive memory B cells in SLE has not been determined. Here, we report on the reactivity of 200 monoclonal antibodies from single IgG+ memory B cells of four SLE patients. The overall frequency of polyreactive and HEp-2 self-reactive antibodies in this compartment was similar to controls. We found 15% of IgG memory B cell antibodies highly reactive and specific for SLE-associated extractable nuclear antigens (ENA) Ro52 and La in one patient with serum autoantibody titers of the same specificity but not in the other three patients or healthy individuals. The germ-line forms of the ENA antibodies were non-self-reactive or polyreactive with low binding to Ro52, supporting the idea that somatic mutations contributed to autoantibody specificity and reactivity. Heterogeneity in the frequency of memory B cells expressing SLE-associated autoantibodies suggests that this variable may be important in the outcome of therapies that ablate this compartment.     

Autoantibodies associated with RNA are more enriched than anti-dsDNA antibodies in circulating immune complexes in SLE

To what extent different autoantibodies accumulate in systemic lupus erythematosus (SLE) immune complexes (ICs), and whether such accumulation is associated with disease activity has been investigated. ICs were isolated from SLE sera by both polyethylene glycol (PEG) precipitation and C1q-binding. Autoantibody specificities were determined using a lineblot assay quantified by densitometry. To compare the relative levels of autoantibodies, levels were normalized to the total levels of IgG measured by ELISA in sera and parallel ICs. Samples were investigated both in a cross-sectional design as well as in a paired design with samples obtained during both active and inactive SLE. All investigated autoantibody specificities except anti-dsDNA were enriched in circulating ICs as compared with parallel sera. The group of antibodies against RNA-associated antigens (anti-RNP/Sm, anti-Sm, anti-SSA/Ro60, anti-SSA/Ro52, anti-SSB/La) all exhibited higher median enrichment than the DNA-associated (anti-dsDNA, anti-histones, anti-nucleosomes) or cytoplasmic (anti-ribosomal P) antigens. In particular autoantibodies against RNP/Sm and SSA/Ro52 had the highest degree of enrichment in SLE PEG precipitates. These findings were corroborated by analysis of autoantibody content in C1q-bound ICs. There was no difference in degree of IC accumulation of the investigated autoantibodies during active and inactive SLE. Our findings demonstrate a difference in enrichment between autoantibodies against RNA- and DNA-associated autoantigens in isolated SLE IC, suggesting that the RNA-associated autoantibodies are more prone to form circulating ICs in SLE, in contrast to antibodies against DNA-associated autoantigens such as dsDNA. These finding have implications in understanding mechanisms of differential autoantibody accumulation in target organs in SLE.     

Clinical features of Sjögren’s syndrome associated with recurrent annular erythema

Our objective was to describe the clinical features of Sjögren’s syndrome (SS) with recurrent annular erythema which resembles subacute cutaneous lupus erythematosus (SCLE), and determine a possible association of anti-SS-A/Ro and/or SS-B/La antibody titers with the episodes of cutaneous manifestation. Recurrent annular erythema was observed in 4% (six patients; five females and one male) of our 143 patients diagnosed as primary SS. All the patients developed annular erythema on the facial area as their initial manifestation when they were between 21 and 31 years old. They had few subjective sicca symptoms, but both anti-SS-A/Ro and SS-B/La antibodies were positive and parotid sialography showed typical findings for SS (subclinical SS). Parotid gland swellings had developed in five of the patients during their follow-up periods, (3–12 years). In addition to the facial area, most patients repeated the cutaneous episodes on extremities and palmar, plantar or auricular areas. Skin biopsy was performed in three patients and the common findings were mononuclear cell infiltrations in the dermis with few epidermal changes. Transient leukopenia (four patients), low titers of anti-DNA antibodies (one patient) and chronic false-positive results of serological tests for syphilis (one patient) were observed. Two of our patients, therefore, temporarily fulfilled four items of the ARA classification criteria for systemic lupus erythematosus (SLE), if their facial erythema was considered as malar rash. Serum antibodies to 52 kDa SS-A/Ro peptides (80%) were more frequently detected in the five patients examined by enzyme-linked immunosorbent assays (ELISA), compared with those to 60 kDa SS-A/Ro peptides (40%). Furthermore, we could serially determine serum anti-SS-A/Ro and SS-B/La antibody titers in three patients by using ELISA for 3 or 4 years. Annular erythema usually developed when the antibody titers became relatively high and disappeared after the treatment with oral prednisolone which suppressed the antibody titers. We could observe five pregnancies in our three patients and all the patients developed annular erythema during their pregnant periods. Their five infants, however, were free from any complications such as neonatal lupus erythematosus and congenital heart block. We conclude that annular erythema is a rare manifestation of SS and develops in relatively young patients who are subclinical for sicca symptoms. The cutaneous episodes seemed to relate with anti-SS-A/Ro and/or SS-B/La antibody titers. Some of the erythema observed in SS patients may belong to SCLE, but they do not usually develop typical SLE. The possibility that SS may be more frequent in the SCLE patients remains to be determined.     

The Ro/SS-A antigen-antibody system

First described in 1969 by Clark et al., the Ro/SS-A antibody system has proved most important in the evaluation of lupus patients possessing prominent photosensitive cutaneous lesions. Ro antibodies are also seen in patients with primary Sj?gren's syndrome, neonatal lupus erythematosus, congenital heart block and ANA-negative LE. The most recent data of biochemical characterization have led to the supposition that these antibodies may exert a direct pathogenic effect. In this review the current knowledge concerning the Ro-antigen-antibody system is summarized.