The demonstration of SS-A/Ro antigen in human fetal tissues and in neonatal and adult skin

High Ro52 expression in spontaneous and UV-induced cutaneous inflammation

Ro52 is an E3 ubiquitin ligase with a recently identified regulatory role in inflammation. The protein is targeted by autoantibodies in rheumatic diseases, and Ro52 autoantibodies are specifically associated with cutaneous lupus erythematosus (CLE) and photosensitivity. The aim of this study was to investigate cutaneous Ro52 expression in CLE patients and to examine whether UVR might modulate Ro52. Ro52 expression was assessed by immunohistochemistry in biopsies derived from CLE lesions (n=25), nonlesional (n=7), and healthy control skin using four anti-Ro52 mAbs generated by us. Ro52 expression was also analyzed in psoriatic, lichenoid, and eczematous lesions. It was increased in the epidermis of spontaneous CLE lesions as compared with unaffected skin of patients and healthy controls. High epidermal Ro52 expression was also observed in other inflammatory dermatoses investigated. Ro52 was upregulated in experimentally photoprovoked CLE lesions as observed by immunohistochemistry in sequential biopsies, which was confirmed in vitro both at the mRNA and protein levels by exposing cultured patient-derived primary keratinocytes to UVR. In conclusion, Ro52 expression is upregulated in keratinocytes in inflammatory skin conditions and in response to UVR. High Ro52 expression might lead to the breaking of tolerance and the generation of Ro52 autoantibodies in genetically susceptible subjects. Further, the upregulation of Ro52 in keratinocytes after sun exposure might also be a triggering factor for skin lesions in patients with Ro52 antibodies.

Issues and advances in the management and pathogenesis of cutaneous lupus erythematosus

Evidence-based therapy for cutaneous lupus is lacking. A new clinical assessment tool for cutaneous lupus, the CLASI score, will enable more standardized assessments of response to therapy. Anti-Ro autoantibodies are associated with photosensitive SLE and SCLE, and they play a role in cell survival following ultraviolet exposure. Ro also functions in quality control of small RNAs, important in the prevention of autoimmune disease. Drug-induced lupus erythematosus can be anti-Ro- or anti-dsDNA-associated; SCLE and photosensitivity are characteristic of Ro-positive drug-induced lupus. Biologic therapies and IVIg are being studied for the treatment of SLE and cutaneous lupus. Large, controlled trials are needed, not only to evaluate newer therapies, but also to substantiate and define the usage of traditional therapies for cutaneous lupus erythematosus.

Pregnancy in Mixed Connective Tissue Disease

This article discusses fetal and maternal morbidity in women who have mixed connective tissue disease.

A serologic marker for fetal risk of congenital heart block

OBJECTIVE

To analyze the humoral immune response to Ro/SSA and La/SSB antigens in detail, in order to identify markers in mothers at high risk of having children with congenital heart block (CHB).

METHODS

Serum samples were obtained from 9 Ro/La-positive mothers who gave birth to affected children, from their 8 newborns with CHB, and from 26 Ro/La-positive mothers whose children were healthy. Antibodies against Ro 52-kd, Ro 60-kd, and La were analyzed by enzyme-linked immunosorbent assay and immunoblotting, using recombinant proteins and synthetic peptides.

RESULTS

IgG anti-Ro 52-kd antibodies were detected in all mothers who gave birth to children with CHB, as well as in their affected children, but were less frequent and at lower levels in control mothers. Fine mapping revealed a striking difference in which the response in mothers with affected children was dominated by antibodies to amino acids 200-239 of the Ro 52-kd protein (P = 0.0002), whereas the primary activity in control mothers was against amino acids 176-196 (P = 0.001). Furthermore, 8 of 9 mothers of children with CHB had antibody reactivity against amino acids 1-135 of the Ro 52-kd protein, containing 2 putative zinc fingers reconstituted under reducing conditions.

CONCLUSION

The results suggest that development of CHB is strongly dependent on a specific antibody profile to Ro 52-kd, which may be a useful tool to identify pregnant Ro/La-positive women at risk of delivering a baby with CHB. Close monitoring of mothers at high risk would enable early detection of a block that is still developing and allow early treatment to combat more serious complications.

The cutaneous pathology of lupus erythematosus: a review

The presentation of lupus erythematosus (LE) ranges from a skin rash unaccompanied by extracutaneous stigmata to a rapidly progressive lethal multiorgan disease. The diagnosis and subclassification is traditionally based on the correlation of serological and clinical findings. The latter include a photoinduced skin rash, arthralgia, arthritis, fever, Raynaud's phenomenon, anemia, leukopenia, serositis, nephritis and central nervous sysdtem disease. The conventional classification scheme includes systemic, subacute cutaneous and discoid LE. Recent advances in our understanding of the cutaneous histopathology which correlates with the traditional forms of LE, along with certain novel LE subtypes, are the focus of this review. In addition to the main subtypes of LE, we will discuss associated vasculopathic lesions and the contribution of immunofluorescence microscopy to the diagnosis of LE and related connective tissue disease syndromes. Consideration will be given to unusual variants of LE such as anti-Ro/SSA-positive systemic lupus erythematosus (SLE), bullous SLE, lymphomatoid LE, lupus erythematosus profundus, drug induced LE, linear cutaneous LE, chiblains LE and parvovirus B19-associated LE.

Role of HLA in congenital heart block: susceptibility alleles in mothers

In congenital heart block (CHB), abnormal maternal immunisation leads to autoantibody production against SS-A/Ro and SS-B/La antigens. These maternal antibodies are transferred across the placenta to the unborn child and are believed to transmit irreversible immunological injury in developing foetal heart tissue, thus causing 3rd-degree atrioventricular block. The mothers may suffer from systemic lupus erythematosus (SLE) or primary Sjögren's syndrome (SS), but they may be asymptomatic. Women with primary SS show a typical autoimmune HLA antigen pattern, namely higher frequency of HLA B8 and DR3 than in the normal population. The HLA pattern may affect individual ability to resist infecting bacteria and viruses and to response in various ways to autoantigens. It is probable that other factors such as genetic regulation of immune response are involved in CHB. We compared the HLA class I and class II alleles of mothers having CHB children with those of women suffering from primary SS and having healthy children, and with those of healthy Finns. Antibodies against 52-kD and 60-kD SS-A/Ro and 48-kD SS-B/La antigens were compared between the two groups of mothers. Our results show that anti-SS-A/Ro antibody-positive mothers all show a strong association with known autoimmune-predisposing HLA alleles, however, the mothers of CHB children differ in some HLA class I alleles, and especially in HLA haplotypes, from mothers of healthy children. Mothers with HLA A1, Cw7, B8 and without B15 are at particularly high-risk of having CHB children.

Neonatal lupus erythematosus

This article discusses neonatal lupus erythematosus, which is a disease of the newborn defined by the presence of maternal autoantibodies and characteristic clinical features in the neonatal period. Although the autoantibodies often are not associated with clinical disease in the mother, neonatal lupus erythematosus is likely the result of fetal or neonatal tissue damage caused by maternally transmitted IgG autoantibodies.

The ultrastructural localization of 60-kDa Ro protein and human cytoplasmic RNAs: association with novel electron-dense bodies

The 60-kDa Ro ribonucleoprotein is an important target of humoral autoimmune responses. However, the ultrastructural locations of the 60-kDa Ro protein and its associated small cytoplasmic RNAs (Y RNAs) have not been previously determined, and the functions of the Ro protein and RNAs are not known. In this study, the cellular locations of the 60-kDa Ro protein and the Ro Y1 and Y4 RNAs are determined by immunoelectron microscopy and in situ hybridization electron microscopy, respectively. Both Ro protein and Y RNAs are concentrated in discrete areas of the nucleoplasm, nucleolus, and cytoplasm of cultured cells and human skin sections. The 60-kDa Ro protein and Y RNAs are also present diffusely in the cytoplasm, where they occur in ribosome-rich regions, and in the nucleus. The presence of Ro ribonucleoprotein components in nucleoli and in ribosome-rich cytoplasmic areas suggests a potential for the involvement of Y RNAs and/or 60-kDa Ro protein in ribosome synthesis, assembly, or transport. Double labeling experiments show that Ro protein and Y RNAs colocalize in the nucleoplasm, nucleolus, and cytoplasm. In addition, aggregates of Y RNA occur unassociated with 60-kDa Ro protein, and aggregates of 60-kDa Ro protein occur unassociated with Y RNA. Aggregates of both Ro protein and Y RNAs label previously unreported nuclear and cytoplasmic electron-dense bodies. We propose that these distinctive Ro-associated electron-dense bodies may represent structure(s) important for cellular transport and/or Ro function.

Subacute cutaneous lupus erythematosus arising in the setting of calcium channel blocker therapy

After 6 months to 5 years of calcium channel blocker (CCB) therapy for arterial hypertension, nine patients developed photoinduced annular or papulosquamous eruptions consonant clinically with subacute cutaneous lupus erythematosus (SCLE). Four patients were receiving diltiazem, four received verapamil, and one was taking nifedipine. Serology showed antinuclear antibodies (ANA) in seven of nine patients, anti-Ro antibodies in five, and anti-La antibodies in five, with three patients having only anti-La antibodies. Skin biopsy specimens in all nine patients were held to be characteristic of SCLE based on light microscopy, direct, and indirect immunofluorescence. The CCB was discontinued in all; in 8 patients in whom the CCB was stopped, the eruption resolved. A proposed mechanism by which the CCBs may have precipitated the eruptions is offered.

Cytomegalovirus infection induces expression of 60 KD/Ro antigen on human keratinocytes

To investigate the effect of human cytomegalovirus (CMV) infection on the expression of Ro autoantigen in human keratinocytes, the binding of anti-Ro peptide antibodies (anti-60 KD/Ro, anti-52 KD/Ro and anti-calreticulin) to cultured human keratinocytes was detected by fixed cell enzyme-linked immunoassay (ELISA), immunofluorescence, flow cytometry (FACS) analysis and immunoblotting. There was a significant increase in the binding of anti-60 KD/Ro antibody but not anti-52 KD/Ro or anti-calreticulin antibody to the surface of cultured keratinocytes at 24 h after CMV infection compared with uninfected cells, by ELISA and immunofluorescence. Surface binding of anti-60 KD/Ro was found in 71.2% (+/- 5.5%) of CMV-infected cells compared with 26.2% (+/- 4.1%) of untreated cells (P < 0.05) by FACS analysis. Similar observations were made with a human serum which contained anti-60 KD/Ro antibodies. Immunoblotting was used to analyse total cellular 60 KD/Ro antigen expression in keratinocytes infected with CMV or without infection. No increase in the intensity of the 60 KD band was found in extracts of the CMV-infected cells, suggesting that the 60 KD/Ro antigen is redistributed from the cytoplasm to the cell surface after viral infection. The effects of CMV infection on cell cultures were compared with those of ultraviolet B (UVB) irradiation. The 60 KD/Ro, 52 KD/Ro and calreticulin were all induced on the UVB-irradiated cell surface but not significant synergistic effect of UVB and CMV was found. This study provides evidence that CMV infection induced 60 KD/Ro antigen expression on the surface of human keratinocytes, suggesting that CMV may play a role in development of skin lesions in systemic lupus erythematosus (SLE).

Heterogeneity in the expression of Ro and La antigens in human skin

OBJECTIVE

To determine whether there are variations in the expression of Ro and La antigens in human skin.

METHODS

Levels of expression of Ro and/or La antigens in 26 specimens of normal human skin (11 sun-exposed, 15 sun-protected) were measured by indirect immunofluorescence with monospecific antisera.

RESULTS

Levels of expression of both antigens varied by more than 2,000-fold in the skin of different individuals. There usually was a correlation between the levels of expression of Ro and La antigens in the same skin specimen. There was no correlation found between the levels of Ro or La antigen expression and sun exposure, nor was there a correlation found between levels of antigen expression and location of the skin on the body.

CONCLUSION

There is a marked heterogeneity in the expression of both Ro and La antigens in the skin of different individuals. The present study findings suggest that the levels of expression of these antigens may play a role in the propensity of some individuals to develop anti-Ro or anti-La antibodies and/or skin lesions associated with the presence of these antibodies.

Impact of ultraviolet irradiation on expression of SSA/Ro autoantigenic polypeptides in transformed human epidermal keratinocytes

SSA/Ro autoantibodies are frequently found in various autoimmune disorders including subacute cutaneous and neonatal lupus erythematosus. SSA/Ro patient sera precipitate a ribonucleoprotein complex consisting of multiple polypeptides and small RNA molecules (hY RNA). Such sera react in Western blot with at least four antigenically distinct proteins having molecular weights of 52-60 kD. Several laboratories have reported increased binding of anti-SSA/Ro patient serum to viable cultured human epidermal keratinocytes following UVB irradiation. However, it is currently unknown which SSA/Ro molecule(s) might be responsible for this increased antibody binding to UVB irradiated keratinocytes. To address this question, we studied the effect of UVB irradiation on the expression of three different polypeptide components of the SSA/Roautoantigen complex (60 kD SSA/Ro, 52 kD SSA/Ro, and 46 kD SSA/Ro (calreticulin) in A431 cells, a transformed human epidermal keratinocytes cell line. Total cellular and cell surface expression of each SSA/Ro antigenic polypeptide was examined by a whole cell ELISA and FACS using rabbit anti-synthetic peptide antisera as probes. Our results suggest that both total cellular and cell surface calreticulin, but not the 60 and 52 kD SSA/Ro polypeptides, is increased after 100 J/M2 of UVB irradiation, indicating that perturbed calreticulin expression may be primarily responsible for the UVB-induced increased binding of anti-SSA/Ro to keratinocytes. These results suggest that calreticulin could be a critical component of the SSA/Ro ribonucleoprotein complex that is involved in the pathogenesis of anti-SSA/Ro-associated photosensitive LE skin lesions.

Neonatal lupus erythematosus. Report of serological and immunogenetic studies in twins discordant for congenital heart block

Autoantibody, HLA studies and C4 phenotypes were performed on twins discordant for isolated congenital heart block. Serum from the mother and cord blood from the infants revealed Ro(SSA) and La(SSB) antibodies in all three sera. No significant difference in Ro(SSA) antibody titre was noted in the cord blood of either twin when compared with maternal titres, as detected by a sensitive ELISA assay. The infants' mother was HLA-DR3 positive. Both infants had identical HLA and C4 phenotypes. Immunoblot analysis revealed that sera from both mother and infants reacted with the 52-kDa Ro(SSA) macromolecule. Quantitative cord blood IgM levels were not elevated in either twin. This study indicates that placental transfer of anti-Ro(SSA) or anti-La(SSB) alone to the fetus is not sufficient for the expression of congenital complete heart block. We conclude from this experiment of Nature that there must be a second event determining which infant develops complete heart block, but this is unknown at present.

La (SS-B)-positive neonatal lupus erythematosus: report of a case with unusual features

Neonatal lupus erythematosus is most often associated with autoantibodies against Ro and La antigens. Rarely, neonatal lupus erythematosus occurs in the absence of Ro antibody. We present a case of La antibody-positive neonatal lupus erythematosus with unusual features.

Neonatal pemphigus vulgaris in a child born to a woman in remission

We describe the tenth reported case of neonatal pemphigus that mimicked Bart's syndrome and review previously published cases. Unlike previous cases, the child was born with significant blistering to a mother who was in complete remission throughout the pregnancy. High antepartum maternal titers of anti-intercellular space antibodies, increased maternal disease activity, and maternal disease that requires high doses of corticosteroids or use of combined therapy correlate with poor fetal outcome, including intrauterine death.

Neonatal lupus erythematosus and maternal lupus erythematosus mimicking HELLP syndrome

A 4-month-old boy had a faint, confluent, macular erythema involving the forehead, nose, and philtrum, and matlike telangiectases over the forehead and eyelids. The clinical features, course, and laboratory studies were characteristic of neonatal lupus erythematosus. He was otherwise healthy and the product of a preterm twin pregnancy complicated by the development of maternal HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome. The patient had elevated Ro(SSA) and La(SSB) antibody titers, and studies performed on maternal blood disclosed positive antinuclear antibodies and elevated Ro and La antibody titers.

Clinical relevance of antibodies to Ro/SS-A and La/SS-B in subacute cutaneous lupus erythematosus and related conditions

Ro/SS-A autoantibodies are frequently associated with subacute cutaneous lupus erythematosus, neonatal lupus erythematosus and Sjögren's syndrome. The Ro/SS-A autoantigen is a ribonucleoprotein complex consisting of at least four protein components and four small cytoplasmic RNA components designated hY RNA 1, 3, 4 and 5. Three of the Ro/SS-A peptides have been isolated and cloned. The function of this ribonucleoprotein complex is as yet unknown.

Characterization of human-human hybridoma monoclonal anti-Ro(SS-A) autoantibodies derived from normal tonsil lymphoid cells

Human-human hybridomas obtained from the separate fusion of tonsillar lymphoid cells from three different normal individuals to the lymphoblastoid cell line GM 4672 were screened by ELISA for the presence of autoantibody to Ro(SS-A). Those anti-Ro(SS-A) reactive hybridomas were then cloned by limiting dilution. Nineteen monoclonal IgM anti-Ro(SS-A) antibodies were obtained, which showed specificity to Ro(SS-A) by ELISA and Western blotting (60 kDa). Some of these monoclonal anti-Ro(SS-A) antibodies showed reactivity to DNA (2/19), cardiolipin (9/19), Sm/RNP (15/19) by ELISA, and to IgG (12/19) and La(SS-B) (19/19) by ELISA and Western blotting. None showed reactivity to the unrelated proteins casein and BSA, nor to RNA. Inhibition studies revealed that the binding to Ro(SS-A) of both IgM hybridoma monoclonal and SLE serum polyclonal IgM anti-Ro(SS-A) antibodies was inhibited with Ro(SS-A), La(SS-B) and Sm/RNP but not with IgG, DNA, RNA and BSA. These data indicate that (1) normal humans have the genetic potential to express antibodies to Ro(SS-A) and (2) the normally derived monoclonal and SLE serum IgM anti-Ro(SS-A) antibodies share similar antigen binding properties and therefore may possibly originate from a common pool of precursor B cells.

Anti-Ro/SS-A and anti-La/SS-B autoantibody levels in relation to systemic lupus erythematosus disease activity and congenital heart block. A longitudinal study comprising two consecutive pregnancies in a patient with systemic lupus erythematosus

OBJECTIVE

To analyze the anti-Ro/SS-A and anti-La/SS-B autoantibody responses, both quantitatively and qualitatively, in relation to the occurrence of congenital heart block (CHB) and disease activity in a patient with systemic lupus erythematosus.

METHODS

The patient's course was carefully documented for a period of 80 months. Specific enzyme-linked immunosorbent assays, a HeLa cell immunoblotting test, and an RNA precipitation assay were used to determine autoantibody levels and fine specificities.

RESULTS

Anti-Ro/SS-A and anti-La/SS-B antibody did not disappear. Levels of anti-Ro/SS-A appeared to fluctuate more frequently than levels of anti-La/SS-B. Fluctuations were unrelated to disease activity or immunosuppressive treatment. There was no characteristic relationship between levels of these antibodies and the occurrence of CHB.

CONCLUSION

The occurrence of CHB cannot be predicted by frequent measurement of anti-Ro/SS-A and anti-La/SS-B levels. The immunoregulatory control of anti-Ro/SS-A and anti-La/SS-B antibodies differs from that of anti-DNA and anti-tetanus toxoid antibodies.

Investigations into Ro-specific antibody-associated congenital cardiac conduction defects

Forty-two babies with different congenital cardiac conduction defects, and in 12 cases the mothers, were tested for autoantibodies to Ro, La, U1RNP and Sm. Ro-specific antibodies were detected most frequently. They were to be found in 16 sera from infants and in 8 maternal serum samples. The occurrence of anti-Ro was associated preferentially with several atrioventricular conduction blocks. The sex relation of anti-Ro associated congenital heart block did not show a typical preference (6 male/10 female). At the time of giving birth, 5 anti-Ro-positive mothers did not have any clinical symptoms of rheumatic autoimmune diseases. Three of them had a first degree atrioventricular block. Our findings indicate that all pregnant women at risk for anti-Ro like connective tissue disease or cardiac conduction defects should be tested for these autoantibodies because of the suspicion of cardiac conduction abnormalities in the offspring. Anti-Ro-positive infants should be examined for structural heart disease by echocardiography.

Anti-Ro/SS-A antibodies in the pathophysiology of congenital heart block in neonatal lupus syndrome, an experimental model. In vitro electrophysiologic and immunocytochemical studies

OBJECTIVE

To determine whether anti-Ro/SS-A antibodies selectively bind to neonatal cardiac cells and alter membrane repolarization.

METHODS

An in vitro electrophysiologic and immunocytochemical experimental model contrasting neonatal and rabbit cardiac tissue was employed.

RESULTS

Sera and IgG-enriched fractions from anti-Ro/SS-A antibody-positive mothers of infants with neonatal lupus erythematosus and congenital heart block bind to neonatal, rather than adult, rabbit cardiac tissue and alter the transmembrane action potential (i.e., inhibit repolarization). The additional presence of anti-La/SS-B antibodies was not additive or synergistic for these immunocytochemical and electrophysiologic features. Sera containing other antibody specificities (i.e., anti-native DNA, cardiolipin, Sm, and nuclear RNP) failed to stain the neonatal cardiac tissue or produced alterations in membrane repolarization.

CONCLUSION

Anti-Ro/SS-A antibodies may play a pathophysiologic role in the development of congenital heart block in neonatal lupus.

Subacute cutaneous lupus erythematosus--the annular variant. A histological and ultrastructural study of five cases

Subacute cutaneous lupus erythematosus is an uncommon, non-scarring variant of lupus erythematosus which has received scant attention in the pathology literature. Its recognition as a distinct entity is important, as, although mild systemic features may be associated, there is characteristically a relative absence of life-threatening renal or central nervous systemic involvement. Subacute cutaneous lupus erythematosus may be clinically sub-divided into the more common annular and the rarer papulosquamous (psoriasiform) variants. A clinicopathological study of five cases of the annular variant is presented with a review of the literature. We highlight the histological and ultrastructural appearances. Discriminatory features from the other variants of lupus erythematosus and additional conditions with which it may be confused, including lichen planus and acute graft-versus-host disease, are discussed.

Collagen vascular diseases of childhood

This article is devoted to collagen vascular diseases of childhood. The connective tissue diseases that are discussed are lupus erythematosus, scleroderma, and dermatomyositis. Of the vasculitic syndromes, Henoch-Schönlein purpura, acute hemorrhagic edema of infancy, and polyarteritis nodosa are discussed. Although the collagen vascular diseases are rare in the pediatric age group, when they occur they can be very serious.

Shuttling of the autoantigen La between nucleus and cell surface after uv irradiation of human keratinocytes

During the past years we have established that the nuclear autoantigen La shuttles between the nucleus and the cytoplasm in tumor cells after inhibition of transcription or virus infection. We reinvestigated this shuttling using primary human keratinocytes from both healthy donors and patients with xeroderma pigmentosum. Ultraviolet irradiation resulted in both an inhibition of transcription and a translocation of La protein from the nucleus to the cytoplasm. After a prolonged inhibition of transcription La protein relocated into the nucleus and assembled with nuclear storage regions. The uv-induced shuttling included a translocation to the cell surface, where La protein colocalized with epidermal growth factor receptors.

Epidermal cell surface-associated IgG in patients with primary Sjögren's syndrome: in vitro evidence for immune complex binding

In vivo deposits of IgG have previously been demonstrated in the epidermal intercellular area of clinically unaffected skin from 68% of patients with primary Sjögren's syndrome (primary SS). This study compared circulating IgG from patients with primary SS with that from secondary SS in their ability to bind normal human epidermal cells in vitro. We observed a granular pattern of IgG binding to the normal epidermal cell surfaces with 9 of 18 sera from patients with primary SS (50%), 3 of 19 sera from patients with SS secondary to rheumatoid arthritis (16%) (p = 0.025), and none of 24 normal control sera (p less than 0.001). In a subsequent analysis of polyethylene glycol separated sera from two normal controls and two primary SS patients, the epidermal IgG binding capacity was found only in the precipitates of the patients. These findings support our previous hypothesis that the in vivo intraepithelial IgG deposits in primary SS patients are due, at least in part, to cell surface-bound immune complexes.

Maternal autoantibodies and pregnancy--II: The neonatal lupus syndrome

NLE is manifested most typically as transient subacute cutaneous lupus lesions or isolated complete congenital heart block. Babies with NLE have maternal anti-Ro/SSA, anti-La/SSB, or anti-U1RNP autoantibodies. It is presumed, but not proven, that transmission of these autoantibodies through the placenta to the baby has resulted in disease. However, other factors such as inflammatory cells or complement activation may be necessary for disease to be expressed. About half of babies reported with NLE have had heart disease and about half have had skin disease. There have been a few reports of liver disease and a few of thrombocytopenia. Any combination of these findings is possible in a given infant. Possibly, other haematologic abnormalities, pneumonitis or neurological disease could occur, but the evidence that these other abnormalities are part of NLE is scant. Mortality in NLE has occurred in babies with severe cardiac disease. It is estimated that 10% or more of babies with cardiac NLE die in infancy. Of the remainder, perhaps half will require permanent pacemaker implantation. Thus, there is substantial morbidity and mortality with cardiac NLE. The skin disease, by contrast, is not serious and typically leaves little or no residua. Individuals who have had NLE may develop connective tissue disease in adulthood. Whether this is a common or an unusual occurrence is not yet known, since a large cohort of individuals with NLE has not yet been followed into adulthood. Mothers of babies with NLE are often initially asymptomatic. With time, they frequently develop connective tissue disease symptoms. In our experience, these have been largely symptoms of Sjögren's syndrome and have generally not been debilitating. Most babies of mothers with anti-Ro/SSA, anti-La/SSB, or anti-U1RNP autoantibodies do not develop NLE. There is no way to determine prospectively which fetus or infant will be affected and which of those affected will have life-threatening disease. Systemic therapies should be reserved for those infants who have life-threatening manifestations of NLE. It is not yet known whether treatment of the mother during gestation will be beneficial or harmful to fetuses with severe NLE cardiac disease.

Liver disease in neonatal lupus erythematosus

We report the cases of neonatal lupus erythematosus associated with significant hepatic involvement in three living infants and in one infant who died 3 hours after delivery. The three living infants had neonatal cholestasis as a major component of their clinical findings. Pathologic changes included giant cell transformation, ductal obstruction, and extramedullary hematopoiesis. Liver involvement has been noted incidentally in children with neonatal lupus erythematosus, but it has generally been attributed to hemodynamic compromise as a result of congenital heart block or systemic toxic reactions. We speculate that neonatal hepatitis proceeding to hepatic fibrosis may occur in neonatal lupus erythematosus, analogous to the occurrence of "idiopathic" congenital heart block. The neonatal hepatitis associated with neonatal lupus erythematosus is a form distinguishable from the "idiopathic" group. Liver involvement may be more common than was previously recognized, and prospective studies to look for maternal autoantibodies in idiopathic neonatal liver disease should be undertaken.

Maternal antibodies to Ro (SS-A) are associated with both early onset of disease and male sex among children with systemic lupus erythematosus

In this study of 71 children with systemic lupus erythematosus (SLE) and 188 of their first-degree relatives, we demonstrated that the development of SLE in male children younger than age 18, and in all children younger than age 10 at the time of diagnosis, is strongly correlated with the presence of antibodies to Ro (SS-A) in the mother's serum. When the relative antibody concentration was quantified, increased quantities of antibody to Ro (SS-A) were also found in mothers of male probands and mothers of probands whose SLE was diagnosed before age 10. No similar association was found for the presence or amount of antibody to Ro (SS-A) in other first-degree relatives or for antibody to La (SS-B) or nuclear RNP in any relative. The explanation for the association of maternal anti-Ro (SS-A) antibodies and early diagnosis of SLE or male sex is not apparent. These findings extend the association of maternal antibodies to Ro (SS-A) from transient "neonatal" SLE to SLE in childhood, and suggest that maternal antibodies to Ro (SS-A) may be of fundamental importance in the pathogenesis of some cases of childhood SLE.

Family studies of congenital heart block associated with Ro antibody

Complete congenital heart block is associated with the presence of maternal autoantibodies to small ribosomal nucleoproteins (such as anti-Ro) which cross the placenta and may be deposited at the site of cardiac damage. Ten such cases of congenital heart block, their mothers, and their siblings were studied. The seropositive mother of one case had a similar conduction defect (bifascicular block) to that in her affected child. None of the siblings examined had cardiac lesions. Six mothers had Ro or La antibody five to 17 years after the birth of the affected child. Four mothers examined 11-32 years after the birth of an affected child were seronegative. Three of these mothers had evidence of a connective tissue disorder. This evidence is consistent with a hypothesis that a maternal viral infection, associated with autoantibody production, leads to virus crossing the placenta, damaging the fetal heart, and eliciting local deposition of maternal antibody.

Transplacentally transferred dermatoses

Transplacentally transferred dermatoses (TTDs) are cutaneous diseases that are transmitted from mother to fetus through the placental circulation. The uniqueness of the maternal-placental-fetal interaction provides many helpful opportunities to enhance our understanding of the pathogenesis and course of these diseases.

Anti-SS-A/Ro SS-B/La antibodies bind to neonatal rabbit cardiac cells and preferentially inhibit in vitro cardiac repolarization

The neonatal lupus syndrome is the most common cause of isolated congenital heart block. There is, at present, little information about the putative role of anti-SS-A/Ro SS-B/La antibodies in the pathogenesis of congenital heart block in the neonatal lupus syndrome. Using an in vitro experimental model, the present study was designed to test the hypothesis that IgG antibodies in the sera of anti-SS-A/Ro SS-B/La-positive mothers of infants with isolated congenital heart block bind to and affect the transmembrane action potential of rabbit cardiac tissue. The results demonstrate a preferential inhibition of membrane repolarization (ADP-50 and ADP-90) and staining of cardiac cells within the neonatal, in contrast to the adult, rabbit heart by sera and IgG-enriched fractions from anti-SS-A/Ro SS-B/La-positive individuals. The results of the electrophysiologic studies demonstrate a pathophysiologic role for the IgG fraction of anti-SS-A/Ro SS-B/La-positive maternal sera in inhibiting neonatal rabbit cardiac repolarization. It is possible that antibodies to similar determinants expressed on the cell membrane of cardiac-conducting cells also may play a pathophysiologic role in the development of idiopathic congenital heart block in humans.

Pattern of cutaneous immunoglobulin G deposition in subacute cutaneous lupus erythematosus is reproduced by infusing purified anti-Ro (SSA) autoantibodies into human skin-grafted mice

Subacute cutaneous lupus and neonatal lupus are closely associated with the presence of anti-Ro (SSA) autoantibodies, but there is no direct evidence establishing a role for anti-Ro (SSA) in these diseases. After parental injection into mice, IgG from sera containing anti-Ro (SSA) will bind human skin grafted onto the mice. To determine whether the antibody binding is due to anti-Ro (SSA), affinity-purified anti-Ro (SSA) and serum depleted of anti-Ro (SSA) were prepared. After injection into human skin-grafted mice, purified anti-Ro (SSA) antibodies bound an antigen in the human skin graft, while preabsorbing anti-Ro (SSA) serum with Ro (SSA) virtually abolished binding to the human skin graft. Moreover, the pattern of IgG deposition was primarily epidermal and was identical in the human skin-grafted mice injected with purified anti-Ro (SSA) when compared with that found in five patients with subacute lupus (four adults, one neonate). These data directly show that anti-Ro (SSA) antibodies bind to the skin, and support the hypothesis that anti-Ro (SSA) autoantibodies are involved in the disease process that produces subacute cutaneous lupus and neonatal lupus.

A monoclonal Ro-antibody and the serum of a Ro-positive patient with subacute cutaneous lupus erythematosus (SCLE) react with basal layers of human epidermis

Skin lesions, especially at areas exposed to sunlight, prove to be a major form of manifestation of diseases related to Ro-antibodies and neonatal-, 'ANA-negative-', and cutaneous types of lupus erythematosus. A monoclonal Ro-antibody established by our group reacts with a 60 kD polypeptide in extracts from human spleen, whereas in extracts from human epidermis the monoclonal Ro-antibody and a purified Ro-antibody from a monospecific serum of a patient with subacute cutaneous lupus erythematosus reacted with a 60 kD and a 48 kD protein. Performing immunofluorescence microscopy on HEp2-cells both antibodies showed a nuclear speckled staining pattern and a reaction with cytokeratin filaments. On skin biopsies obtained from the patient, predominantly the basal layers of the proliferative stratum germinativum demonstrated a high rate of immunofluorescence; antigen-expression seems to depend on sunlight exposure. From these data we assume that, especially in subacute cutaneous lupus erythematosus, cross-reaction of the Ro-antibody with one of the lower molecular keratins happens in that area of human epidermis which histologically shows cellular destruction.

Immunopathologic studies of cutaneous lupus erythematosus

The studies, as outlined above, strongly suggest that there may be several pathophysiologic mechanisms resulting in the development of cutaneous lupus lesions. It appears that all lupus lesions are associated predominantly with a T-cell infiltrate. Based upon the studies of the neonatal lupus infants, it has been hypothesized that the U1RNP and Ro(SS-A) autoantibodies of maternal origin play a direct pathologic role in the genesis of the annular polycyclic SCLE lesions and this may be mediated by antibody-dependent cellular cytotoxicity mechanisms in which the antibody binds to the respective antigen present on the keratinocyte plasma membrane and the effector cells are T cells derived from the infants. Other studies, using direct immunofluorescence techniques, have demonstrated an association of cutaneous lupus lesions occurring in the presence of immunoglobulin and complement at the dermal/epidermal junction (positive lupus band test) in which the neoantigen of the complement membrane attack complex (C5b-C9) is detected. These data have been interpreted as indicating that immunoglobulin and complement, perhaps in the form of immune complexes, may play a role in the pathogenesis of some cutaneous lupus lesions. Additional studies have determined that there is a substantial number of lupus patients with cutaneous disease, without antinuclear antibodies, who fail to demonstrate the deposition of immunoglobulin and complement at the dermal/epidermal junction. Furthermore, other studies have indicated that ultraviolet light is capable of inducing lesions in lupus patients that histologically are identical to those of cutaneous lupus erythematosus but that failed to demonstrate the deposition of the immunoglobulin and complement components. Since discoid lupus lesions demonstrate a preponderance of T cells, it has been proposed that some of these lesions are the direct result of a T-cell cytotoxic event. However, the nature of the autoantigens responsible for this putative T cell-mediated cytotoxic response is unknown at the present time. The role of ultraviolet light in the genesis of the cutaneous lupus lesions appears to involve, within the epidermis, the generation of autoantigen macromolecules which then react with autoantibodies or specific T cells of the lupus host.