Immune responses to SS-A 52-kDa and 60-kDa proteins and to SS-B 50-kDa protein in mothers of infants with neonatal lupus erythematosus

Prenatal predisposing factors associated with neonatal lupus erythematosus

OBJECTIVES

To identify the prenatal predisposing factors related to neonatal lupus erythematosus (NLE).

MATERIALS AND METHODS

A retrospective case-control study was made of 131 pregnant women with positive anti-Ro or anti-La autoantibodies and known neonatal outcomes between January 2002 and December 2019 at Siriraj Hospital, Bangkok, Thailand. There were 101 unaffected neonates and 30 NLE cases confirmed postnatally. Demographic and clinical data of the mothers and neonates with and without NLE were statistically compared.

RESULTS

NLE was diagnosed in 30 out of 131 cases. A multivariate analysis identified the following significant factors for NLE: maternal anti-La antibodies (odds ratio (OR), 3.591; p = 0.030); and maternal treatment with either hydroxychloroquine (OR, 0.082; p = 0.001) or prednisolone (OR, 0.136; p = 0.017). Of the significant variables examined in the multivariate analysis models, high levels of maternal anti-La antibodies were found to be the strongest predictor of noncardiac NLE (OR, 4.558; p = 0.032), while a female baby was significantly higher in pregnancies complicated by cardiac NLE (OR, 5.374; p = 0.046). Hydroxychloroquine still provided a protective effect for both cardiac and noncardiac NLE (p = 0.039 and 0.032, respectively).

CONCLUSIONS

The maternal anti-La antibodies were a beneficial predictor for NLE, especially as their high titers were influentially associated with noncardiac features. A female fetus seemed to present an increased risk for developing a congenital heart block. Nevertheless, the treatment with hydroxychloroquine during the pregnancies demonstrated a potentially protective factor against both cardiac and noncardiac manifestations.

The importance of the level of maternal anti-Ro/SSA antibodies as a prognostic marker of the development of cardiac neonatal lupus erythematosus a prospective study of 186 antibody-exposed fetuses and infants

OBJECTIVES

The purpose of this study was to determine whether cardiac complications of neonatal lupus erythematosus (NLE) are related to maternal anti-Ro and anti-La autoantibody-levels.

BACKGROUND

Autoantibody-positive mothers are frequently referred for serial echocardiography because of the elevated fetal risk of developing immune-mediated heart block. Little is known why only some and not all offspring are affected.

METHODS

All cases referred since 2000 for serial fetal echocardiography or cardiac complications related to maternal antibodies were included. Patients without cardiac NLE (group 1) and with cardiac NLE (group 2) were compared. Antibody levels were measured by enzyme-linked immunosorbent assay with a cutoff value of 8 U/ml for a positive test result.

RESULTS

Group 1 included 146 serially screened fetuses with normal pregnancy outcomes. Group 2 consisted of 40 fetuses/neonates with a diagnosis of heart block or endocardial fibroelastosis or both, and included 4 fetuses diagnosed during serial screening. All cardiac complications were associated with moderate (>or=50 U/ml; 15%) or high (>or=100 U/ml; 85%) maternal anti-Ro levels, independently of anti-La antibody titres. The event rate of complete heart block was 5% for prospectively screened fetuses with Ro-values >or=50 U/ml (odds ratio: 7.8) and 0% for fetuses with lower titres (p < 0.0001). Infants with pre-natal exposure to high-titre anti-La levels >or=100 U/ml were the most likely to have noncardiac features of NLE (event rate: 57%; odds ratio: 4.7).

CONCLUSIONS

Our findings support that the amount of maternal antibodies, rather than their presence, is associated with fetal tissue injury. As anti-Ro levels correlate with the risk of cardiac complications, serial echocardiography should be limited to women with high anti-Ro-titres.

Anti-La negative cutaneous lupus erythematosus in a newborn

A newborn presented with erythematous lesion over face, which appeared soon after birth. Diagnosis of neonatal lupus erythematosus (NLE) was confirmed by positive anti-Ro SSA antibody and skin biopsy. But anti-La SSB antibody was negative. Her hepatic transaminases were high. But no cardiac manifestations were noted.

Neonatal lupus and IUGR following alpha-interferon therapy during pregnancy

Interferon alfa-2a is a cytokine produced by recombinant DNA techniques and has antiproliferative, antiviral and immunomodulating effects. A number of case reports in the past have suggested relative safety of alpha-interferons during pregnancy with little or no effect on the fetus. A 15-year-old adolescent became pregnant while receiving alpha-interferon for essential thrombocythemia. She delivered a small-for-gestational age baby girl at 33 weeks gestation. The infant displayed a facial rash characteristic of neonatal lupus and transient thrombocytopenia; maternal and neonatal serologies were typical for drug-induced lupus. These findings suggest probable association between maternal use of alpha interferon and adverse effects in the fetus.

Neonatal lupus erythematosus presenting as papules on the feet

We describe a case of neonatal lupus erythematosus in a 4-week-old male baby presenting with nodules/papules on the plantar surface of both feet. Skin histology of the right foot papule was consistent with lupus erythematosus. Annular lesions more typical of this condition then appeared later and maternal antibodies were positive for speckled antinuclear antibodies (1:5120), anti-Ro/SSA and anti-La/SSB(+), rheumatoid factor 1380.0 IU/mL. The patient had no evidence of cardiac, haematological or hepatobilary involvement. Although the mother was asymptomatic, the maternal grandmother had recently been diagnosed with Sjögren's syndrome.

[Neonatal lupus syndrome]

Neonatal lupus syndrome is a passively acquired autoimmune syndrome in which pathogenic autoantibodies (anti-SSA/Ro, anti-SSB/La, and both, or rarely anti-U(1)RNP antibodies) are transmitted from a mother to her fetus through the placenta. The major clinical manifestations in the infants are cardiac (congenital heart block), dermatologic (skin lesion), hepatic (elevated hepatic enzymes), and hematologic (cytopenia). Congenital complete heart block (CCHB) is irreversible, while noncardiac manifestations are transient, resolving by one-year-old of age without specific treatments. Two prospective studies show that the prevalence of CCHB in children from a woman previously known to have anti-SSA/Ro antibodies is approximately 2%. However, when the previous pregnancy is complicated by CCHB and skin lesion, the recurrence rates of these symptoms go much higher to 10.5% and 26%, respectively, in the subsequent pregnancy.

Relationship of maternal autoimmune response to clinical manifestations in children with congenital complete heart block

OBJECTIVE

To study the autoimmune response in mothers of children with congenital heart block (CHB) diagnosed at different ages and with different clinical manifestations.

PATIENTS AND METHODS

Clinical data and sera for the determination of immunological tests were available from 104 mothers of 113 children born between 1950 and 2000 and diagnosed with CHB before the age of 16 y. Prenatal diagnosis was performed in 74 (65%) children of 65 mothers, and 39 (35%) children had postnatal diagnosis of CHB. Maternal antibodies to 52 kd and 60 kd SS-A, and to 48 kd SS-B were determined by time-resolved fluoroimmunoassay (TR-FIA) and to antinuclear antibodies (ANA) by immunoflurescense (IF).

RESULTS

Out of the 65 mothers of children with in utero diagnosed CHB, 88% had antibodies to 52 kd SS-A and 83% had ANA. Antibodies to 60 kd SS-A and 48 kd SS-B were less frequently present, in 48% and in 54% of the mothers, respectively. Seven (11%) of the mothers were negative by all immunoassays. Of the 13 mothers of children with in-infancy diagnosed CHB, one mother had high-titer ANA. After 1 y of age, CHB was diagnosed in 26 children; at 1 to 6 y in 16 and after 7 y in 10 children; 1/16 and 1/10 patients had positive antibodies. In all twin pregnancies (n = 4) and in all families with recurring cases of CHB (n = 5), maternal antibodies were positive in at least one assay. The titer of 48 kd anti-SS-B antibodies was significantly higher in children with cutaneous neonatal lupus (98.1 vs 41.0; p = 0.02). All mothers whose children died before the age of 4 y (n = 8) and 85% (11/13) of mothers whose children developed cardiomyopathy had elevated antibody titers in at least one assay. However, we could not find any prognostic value of maternal antibody levels or specificities on the clinical outcome of the children with CHB.

CONCLUSIONS

Although rare, late detection or postnatal progression of CHB in antibody-mediated CHB should be taken into consideration. Maternal antibody levels or specificities have prognostic effect neither on the clinical outcome of the child with CHB nor on the risk of reappearance in the same family.

Pneumocystis carinii mimicking neonatal lupus erythematosus-related pneumonitis

Neonatal lupus erythematosus (LE) is a rare disease associated with the transplacental passage of maternal autoantibodies to infants who manifest congenital heart block, skin disease, and less commonly, hematologic and hepatic disease. Pulmonary disease is a rare manifestation of neonatal LE and has presented as transient pneumonitis. In this report we describe an infant with neonatal LE who had the classic skin and hematologic findings of the disease in addition to pulmonary disease which might be attributed to neonatal LE-related pneumonitis, but in fact was caused by a concomitant Pneumocystis carinii infection. This case demonstrates the importance of looking for other causes of pulmonary disease in neonatal LE patients.

Autoantibodies Associated with Rheumatic Diseases

The identification of circulating autoantibodies contributes to the correct diagnosis as well as to the follow-up of rheumatic diseases. Some autoantibodies are even included in diagnostic and classification criteria for these types of autoimmune diseases. There are several relatively specific screening and identification methods for the measurement of autoantibodies available. The type of assay crucially influences the diagnostic value of the parameters. In general, routine laboratories should prefer enzyme immunoassays (ELISA) using well characterized antigens, although ELISA tests tend to produce more false-positive and true weakly positive results, which reduce their positive predictive value. Therefore one should be aware that laboratory results can only be properly interpreted when there is a correlation with the clinical situation and when the limitations of the technologies used for autoantibody identification have been taken into consideration. A diagnostic algorithm consisting of screening and identification steps should be established by each laboratory in order to create a rational, evidence-based and cost-effective basis for the diagnosis of rheumatic diseases.