CASE REPORT article

Front. Pediatr., 23 August 2023

Sec. Pediatric Rheumatology

Volume 11 - 2023 | https://doi.org/10.3389/fped.2023.1239327

Anti-U1RNP-70kD-positive case of neonatal lupus presenting with seizure and incomplete heart block: a case report and literature review

  • 1. Education Institute, Sheikh Khalifa Medical City (SKMC), Abu Dhabi, United Arab Emirates

  • 2. Sheikh Khalifa Medical City(SKMC), Purelab-Purehealth, Abu Dhabi, United Arab Emirates

  • 3. College of Medicine and Health Sciences, United Arab Emirates University (UAEU), Al Ain, United Arab Emirates

  • 4. Department of Pediatric Neurology, Sheikh Shakhbout Medical City (SSMC), Abu Dhabi, United Arab Emirates

  • 5. Department of Pediatric Rheumatology, Sheikh Shakhbout Medical City (SSMC), Abu Dhabi, United Arab Emirates

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Abstract

Neonatal lupus erythematosus (NLE) is an autoimmune disease caused by the transplacental passage of anti-Ro/SS-A and anti-La/SS-B. This can be less commonly seen with U1-ribonucleoprotein (U1RNP). Our patient is a 7-day-old male, who first presented with seizures. In addition, during an electroencephalogram, he was found to have an irregular heart rhythm. Looking further into the history, we found that the mother was aware that she had systemic lupus erythematosus (SLE). However, she had not been followed up with a rheumatologist. The workup for NLE found a negative anti-Ro/SS-A and anti-La/SS-B, with a positive U1RNP-70kD. U1RNP-70kD is a diagnostic test for mixed connective tissue disease in adults, but no research has been done on its significance in NLE. Despite having SLE, the infant’s mother did not receive surveillance during her pregnancy, as the current guidelines are tailored for mothers with anti-Ro/SS-A and anti-La/SS-B. As a result, this calls for the extension of these guidelines to include the U1RNP-70kD antibody. In this case, the 70kD subtype of U1RNP was positive, which may have had a role to play in this unusual presentation. However, further research is needed to improve the care of mothers and babies with U1RNP-70kD.

1. Introduction

Neonatal lupus erythematosus (NLE) is an autoimmune disease caused by the transplacental passage of pathological autoantibodies from the mother to the fetus. These antibodies are the anti-Ro/SS-A and anti-La/SS-B and less commonly the anti-U1-ribonucleoprotein (U1RNP) (1). Congenital heart block (CHB) occurs in 2% of mothers with anti-Ro/SS-A and/or anti-La/SS-B. This number increases up to 20% with subsequent pregnancies. The diagnosis for NLE involves the presence of one of the above antibodies in addition to a system involvement. It may present with multi-system involvement, including the skin, cardiac, hematologic, neurologic, and/or hepatobiliary system, usually manifesting as cutaneous lesions, cytopenia, elevated aminotransferases, and rarely heart block (1). Cutaneous manifestations have been associated with positive anti-U1RNP (1). Skin, hepatobiliary, and hematologic symptoms usually resolve within 6 months with the washout of maternal antibodies. On the other hand, the development of complete CHB is irreversible (2), with a mortality rate of 4%–29% (2). The cardiac involvement is not only limited to CHB but can also include structural abnormalities. In addition to CHB, the structural heart abnormalities carry a higher rate of mortality. Thus, detection and early intervention are required to decrease this risk of mortality (2). Here, we detail a case of NLE presenting with seizure and incomplete heart block, with positive anti-U1RNP-70kD and negative anti-Ro/SS-A and anti-La/SS-B.

2. Description of the case

This 7-day-old male was born full term, by a normal vaginal delivery. The mother was gravida 2, para 2. She was found to have group B streptococcus (GBS) and appropriately received antibiotics. She was also known to have hypothyroidism and was on levothyroxine but with an otherwise unremarkable perinatal history. The infant was brought to the emergency department (ED) with a cough and an increased difficulty in breathing. He was found to have respiratory syncytial virus (RSV) and was discharged with supportive management. The next day, he presented again to the ED with decreased activity and decreased oral intake. The mother reported symptoms of choking, coughing up frothy secretions, and experiencing weak extremities for a period of 4–5 min. A physical examination showed a hypoactive infant with normal suckling and Moro reflexes, an open anterior fontanelle, and no skin lesions. He was hemodynamically stable with no fever, weighing 2.6 kg (in the second percentile), with a length of 45 cm (less than second percentile), and a head circumference of 33 cm (in the fourth percentile).

The infant was admitted to the ward for observation, further management, and investigation. Full septic workup was sent, except for the lumbar puncture, which was refused by the parents. An electrocardiogram (ECG) and an electroencephalogram (EEG) were ordered. During the EEG session, the neurology physician noted an irregular heart rhythm on the ECG monitor, which was an evidence of an incomplete heart block (Figure 1). The extended history taken revealed that the mother had systemic lupus erythematosus (SLE), which, despite her being aware of it, was not previously revealed. She did not disclose this earlier as she did not think that it was of relevance because she was in remission, stopped taking her medication, and had not been followed up with a rheumatologist for over 18 months. This history alerted the team to investigate the infant for NLE. The neonate was then put on a Holter monitor and was sent to the pediatric intensive care unit (PICU) for close monitoring.

Figure 1

The EEG reported an underlying regional disturbance and a low threshold for seizures (the background was continuous with mixed frequencies and short epochs of discontinuity, in addition to frequent bilateral temporal sharp wave activity with no clinical activity). Subsequently, the patient was loaded with an intravenous (IV) levetiracetam at a dose of 30 mg/kg, with a maintenance dose of 15 mg/kg every 12 h. He was also started on empiric antibiotics, cefotaxime, and ampicillin for possible meningitis.

The detailed laboratory studies for the patient are presented in Table 1. In summary, his complete blood count and renal and liver function tests were within a normal range. His ammonia and glucose levels were normal. The anti-nuclear antibody (ANA) by indirect immunofluorescence (IIF) was 1:320 (positive speckled), complement 3 (C3) was low, complement 4 (C4) was normal, the extractable nuclear antigen (ENA) antibody test was positive, anti-Sm/RNP was detected by solid-phase assay, and anti-Sm antibody, anti-Ro/SS-A, and anti-La/SS-B were negative. The other autoantibodies were negative. His cardiac N-terminal prohormone of brain natriuretic peptide (NT-proBNP) and troponin T were high. His blood and urine cultures had no growth of any organism.

Table 1

PatientReferenceInterpretation
White blood cells (×109/L)7.985.00–21.00Normal
Red blood cells (×1012/L)3.923.90–6.30Normal
Hemoglobin (g/L)127125–205Normal
Hematocrit0.3820.390–0.630Low
MCV (fl)97.486.0–124.0Normal
MCH (pg)32.431.0–37.0Normal
MCHC (g/L)332305–355Normal
Platelets (×109/L)337140–400Normal
Glucose (point of care) (mmol/L)3.93.9–7.8Normal
Sodium (mmol/L)138133–146Normal
Potassium (mmol/L)5.553.40–5.10High
Chloride (mmol/L)10498–110Normal
Bicarbonate (mmol/L)2422–29Normal
Creatinine (μmol/L)4015–91Normal
Urea (mmol/L)3.372.80–8.10Normal
Bilirubin total (μmol/L)139.0Normal
Bilirubin direct (μmol/L)7.6<10.0Normal
Alkaline phosphatase (IU/L)10335–449Normal
Aspartate transaminase (IU/L)29<50Normal
Alanine transaminase (IU/L)<5<50Normal
Ammonia (μmol/L)4816–60Normal
NT-proBNP (pg/ml)1,533High
Troponin T (ng/L)120High
CRP (mg/L)14.70<5.00High
ANA1:320High
C3 (g/L)0.740.90–1.80Low
C4 (g/L)0.180.10–0.40Normal
DNA Ab (DS) (IU/ml)15.7<26.9Normal
ENA (CU)164.9<20.0High
SmRNPPositive
Sm AbNegative
Anti-U1RNP-70kDPositive
SS-A AbNegative
SS-B AbNegative
Ro-52 AbNegative
DFS70Negative
DAT PolyNegative

Patient's investigations with reference and interpretations.

Ab, antibody; ANA, anti-nuclear antibody; C3, complement 3; C4, complement 4; CRP, C-reactive protein; DAT, direct antiglobulin test; DFS70, anti-dense fine speckled 70; DsDNA, double-stranded deoxyribonucleic acid; ENA, extractable nuclear antigens; MCH, mean corpuscular hemoglobin; MCHC, mean corpuscular hemoglobin concentration; MCV, mean corpuscular volume; NT-proBNP, N-terminal prohormone of brain natriuretic peptide; SS-A, anti-Sjogren's syndrome A; SS-B, anti-Sjogren's syndrome B; U1RNP, U1-ribonucleoprotein.

As for the imaging, the echocardiogram showed a structurally normal heart with no signs of pulmonary hypertension. The cranial ultrasound showed a slightly increased periventricular echogenicity bilaterally, probably due to mild leukomalacia. No hemorrhage or hydrocephalus was observed. A brain computerized tomography (CT) angiogram was performed to exclude any vascular phenomena as a possible etiology for the seizure in the context of NLE, and it was found to be normal. The Holter monitor showed episodes of sudden sinus slowing, followed with junctional escape beats and periods of marked sinus bradycardia. He remained stable under observation in the PICU without requiring a pacemaker or any additional interventions. He was then discharged and put on oral levetiracetam at a dose of 40 mg twice per day.

Two weeks later, a follow-up in the clinic revealed no recurrence of seizures or development of new symptoms. Repeated laboratory workup showed improved cardiac function tests, with a decrease in ENA, but levels had not yet normalized. The EEG, ECG, and echocardiogram were normal. A month after discharge, a repeat EEG showed a normal result; therefore the levetiracetam was discontinued. With a normal physical exam, a follow-up at 6 months of age revealed that he was appropriately meeting his developmental milestones and the parents refused to repeat the laboratory workup at this visit.

Retrospectively looking at this case, although the mother did not disclose her history of SLE to the pediatric team, she was followed up with an obstetrics medicine physician who was aware of her SLE and immunology status. Since the mother lacked the classical anti-Ro/SS-A and anti-La/SS-B, this did not prompt the obstetrician to do further surveillance or education regarding the possibility of NLE. Table 2 presents the mother's immunology in early pregnancy.

Table 2

MotherReferenceInterpretation
ANA1:640
C3Not done
C4Not done
Cardiolipin IgG (CU)19.1<20.0Normal
Cardiolipin IgM (CU)2.1<20.0Normal
DNA Ab (DS) (IU/ml)97.3<26.9High
ENA (CU)>429.4<20.0High
SmRNPPositive
Sm AbNegative
Anti-Ro/SS-ANegative
Anti-La/SS-BNegative
Scl 70Negative
JO-1 AbNegative

Mother's autoantibodies in early pregnancy.

Ab, antibody; ANA, anti-nuclear antibody; C3, complement 3; C4, complement 4; DsDNA, double-stranded deoxyribonucleic acid; ENA, extractable nuclear antigens; SS-A, anti-Sjogren's Syndrome A; SS-B, anti-Sjogren's syndrome B.

3. Discussion

In this case, the interpretation of the immunology workup is important. Please note that this panel may appear differently in different labs. To summarize the immunology workup, ENA was high with negative anti-Ro/SS-A and anti-La/SS-B and positive Sm/RNP with negative anti-smith (anti-Sm) antibody. Sm/RNP is also known as U1-small nuclear RNP (U1-SnRNP) complex (Figure 2) (3). It is an ENA and is a complex protein consisting of both anti-Sm and anti-RNP. Both have their own subtypes. The protein subtypes of anti-RNP are 70kD, A, and C. U1RNP A and C are seen more in SLE patients, while U1RNP-70kD is specific for mixed connective tissue disease (MCTD) (4). In our lab, the anti-Sm is ordered as a separate entity, and it is negative. Hence, this concludes that the anti-RNP is positive. The U1RNP subtypes are not routinely tested as they pose no clinical significance or implication. We ordered it for our patients for future reference and for further studies. We have found that the U1RNP-70kD subtype is positive. No available data are reported on U1RNP subtypes in the literature in the context of NLE to compare this with.

Figure 2

Limited data on the clinical significance and pathogenicity of U1RNP subtypes in NLE were found; however some evidence from adult studies was outlined. Specifically looking at the central nervous system (CNS) involvement, the cerebrospinal fluid (CSF) of SLE and MCTD had been examined and found to have elevated indices of anti-U1RNP-70kD (5). Another study investigating the U1RNP in MCTD found that CNS involvement is higher in MCTD patients who have symptoms associated with SLE (6). The long-term follow-up of patients with MCTD found that 17% developed CNS involvement (7). Different subtypes of U1RNP may be associated with different clinical manifestations; therefore, we hypothesize that neonates of SLE mothers with U1RNP A/C present with cutaneous lesions, while neonates of SLE mothers with U1RNP-70Kd present with CHB and/or CNS involvement.

NLE rarely presents with neurologic manifestations. Few patients described in the literature that presented with neurologic symptoms, with the majority of cases finding CNS abnormalities in the imaging as a part of the NLE evaluation, were reported. Subependymal cysts, increased echogenicity, and hydrocephalus were the most widely seen radiologic changes. Table 3 summarizes the NLE patients in the literature with CNS manifestations (8–22). Psychiatric research and publications not in English are not included in this table. Development of seizure was reported in 10 patients (14, 16, 17, 19, 20, 22), eight of which had an underlying cerebral infarct or hemorrhage. The antibody profile is summarized in Table 3. One of the patients without a stroke is the most similar to our patient (14), but unfortunately, the U1RNP profile was not reported. The other symptomatic patients varied in presentation having myelopathy (8), spastic paraparesis (9), tetraplegia (15), facial nerve palsy with hemiparesis (18), phrenic nerve palsy (21), and hydrocephalus (10, 23). The majority of these neurologic symptoms resolved with no long-term sequelae.

Table 3

Year (reference)CaseNeurologic manifestationNeurologic symptoms or part of NLE evaluation?Child antibodiesOther involvement
1987, Kaye et al. (8)1Lower limb spasticity, increased reflexes, and contracture at the ankleSymptomaticAnti-Ro/SS-APositiveRash
Anti-La/SS-BNegative
1993, Bourke et al. (9)1Spastic diplegia of lower limbsSymptomaticANA
Anti-Ro/SS-A
Anti-La/SS-B
PositiveRash, thrombocytopenia, transaminitis
1994, Nakayama-Furukawa et al. (10)1Hydrocephalus. CT head showed large ventricles and widening of extracerebral spaceSymptomaticANA
Anti-Ro/SS-A
Anti-La/SS-B
PositiveRash, annular erythema
Anti-RNP
Anti-Sm
Negative
2Non-obstructive hydrocephalus. Ventriculoperitoneal shunt was placedSymptomaticNot done. Sister of the first case.Rash, annular erythema
1996, Cabañas et al. (11)1Cerebral ultrasound scans showed hyperechogenic areas in the thalamus and/or basal ganglia (HTBG) indicating vasculopathyPart of NLE evaluationANA
Anti-Ro/SS-A
Anti-La/SS-B
PositiveCHB, rash, thrombocytopenia
2ANA
Anti-Ro/SS-A
Anti-La/SS-B
PositiveCHB
3ANA
Anti-Ro/SS-A
PositiveCHB
2003, Prendiville et al. (12)1Cerebral US: increased echogenicity of the white matter, subependymal cysts, and echogenic lenticulostriate vessels
Brain CT: symmetrical, diffusely reduced attenuation of the cerebral white matter with normal attenuation of the gray matter
Part of NLE evaluationANA
Anti-Ro/SS-A
Anti-La/SS-B
PositiveRash, hepatosplenomegaly with transaminitis, thrombocytopenia, irregular distal femoral metaphyses
2Cerebral US: Increased white matter echogenicity, bilateral subependymal cysts
CT: Reduced attenuation of cerebral white matter, left subependymal hemorrhage and bilateral  subependymal cysts
Part of NLE evaluationAnti-Ro/SS-APositiveRash, thrombocytopenia
33 weeks of age
Normal cerebral US
Brain CT: Patchy peripheral reduced attenuation of cerebral white matter
Part of NLE evaluationAnti-Ro/SS-A
Anti-La/SS-B
PositiveRash
4At birth
Brain US: Mildly enlarged frontal horns of lateral ventricles
Brain CT: Reduced attenuation of cerebral white matter, mildly enlarged frontal horns and third ventricle
Part of NLE evaluationAnti-Ro/SS-A
Anti-La/SS-B
PositiveRash and thrombocytopenia
5At birth
US: Increased white matter echogenicity, bilateral subependymal cysts, echogenic lenticulostriate vessels
CT: Reduced attenuation of cerebral white matter, normal scan at 13 months of age
Part of NLE evaluationAnti-Ro/SS-A
Anti-La/SS-B
PositiveHepatosplenomegaly with transaminitis and rash
64 months of age
Cerebral US and CT: Ventriculomegaly and increased cortical subarachnoid spaces
Part of NLE evaluationANA
Anti-Ro/SS-A
Anti-La/SS-B
PositiveRash, hepatomegaly with transaminitis, hemorrhagic gastritis at 5 months
72 months of age
Brain CT: Bilateral basal ganglia calcification, ventriculomegaly
Part of NLE evaluationANA
Anti-Ro/SS-A
Anti-La/SS-B
PositiveRash and neutropenia
8At birth
Cerebral US: Bilateral subependymal cysts
Brain CT: Reduced attenuation of cerebral white matter
Part of NLE evaluationAnti-Ro/SS-A
Anti-La/SS-B
PositiveRash
9At 3 months, cerebral US and brain CT were normalPart of NLE evaluationANA
Anti-Ro/SS-A
Anti-La/SS-B
PositiveRash and neutropenia
10At 2 months, cerebral US was normalPart of NLE evaluationANA
Anti-Ro/SS-A
Anti-La/SS-B
PositiveRash and neutropenia
11At 2 months
Cerebral US: Echogenic lenticulostriate vessels
Brain CT: Bilateral basal ganglia calcification
Part of NLE evaluationANA
Anti-Ro/SS-A
Anti-La/SS-B
PositiveRash and neutropenia
2004, Zuppa et al. (13)1Cerebral US: Subependymal pseudocystPart of NLE evaluationAnti-Ro/SS-A 24PositiveThrombocytopenia
2Cerebral US: Subependymal pseudocystPart of NLE evaluationAnti-Ro/SS-A 26PositiveThrombocytopenia, anemia, neutropenia, hepatic involvement
3Cerebral US: NormalPart of NLE evaluationAnti-Ro/SS-A 155
Anti-La/SS-B 126
PositiveHepatic involvement
4Cerebral US: Bilateral subependymal pseudocystPart of NLE evaluationAnti-Ro/SS-A 158
Anti-La/SS-B 154
PositiveNone
5Cerebral US: Subependymal pseudocystPart of NLE evaluationAnti-Ro/SS-A 160PositiveNone
6Cerebral US: NormalPart of NLE evaluationAnti-Ro/SS-A 194
Anti-La/SS-B 97
PositiveHepatic involvement
7Cerebral US: Subependymal hemorrhagePart of NLE evaluationAnti-Ro/SS-A 209
Anti-La/SS-B 140
PositiveHepatic involvement
8Cerebral US: NormalPart of NLE evaluationAnti-Ro/SS-A 187
Anti-La/SS-B 149
PositiveAnemia
9Cerebral US: Subependymal hemorrhagePart of NLE evaluationAnti-Ro/SS-A 203
Anti-La/SS-B 143
PositiveHepatic involvement
10Cerebral US: Subependymal pseudocystPart of NLE evaluationAnti-Ro/SS-A 305
Anti-La/SS-B 55
PositiveNeutropenia
11Cerebral US: NormalPart of NLE evaluationAnti-Ro/SS-A
Anti-La/SS-B
PositiveCHB, anemia
2005, Lin et al. (14)1Two episodes of focal seizures.
Brain ultrasonography: Normal ventricular size without a midline shift or intracranial or intraventricular hemorrhage.
Brain CT showed generalized low density of the periventricular and deep white matter
EEG: Rare spikes axial to the right parietal area
SymptomaticANA
Anti-Ro/SS-A
Anti-La/SS-B
PositiveThrombocytopenia, rash, anemia
Anti-DsDNANegative
2012, Chen et al. (15)1Brain CT evidence for bilateral occipital hemorrhage. He was later diagnosed with tetraplegic cerebral palsySymptomaticANA
Anti-Ro/SS-A
PositiveThrombocytopenia and leukopenia
Anti-La/SS-B Anti-Sm
Anti-RNP
Negative
2014, Saini et al. (16)12-month-old girl with 5 days of fever, developed left-sided seizure. The focal seizure recurred on day 14 of illness. She had hypertonia and brisk muscle reflexes on the left side. MRI brain showed right hemispheric infarct with subdural hemorrhage. CT of head and neck vessels were consistent with vasculitis. At 15 months of age, she has mild motor delay with left hemiparesisSymptomaticANA
DsDNA
Negative
2014, Döring et al. (17)1Focal seizure at day 1, confirmed by EEG. MRI brain revealed multiple ischemic areas in the distribution of the middle and posterior cerebral artery on the left side. Child fully recoveredSymptomaticANA
Anti-U1-snRNP Anti-Sm
PositiveRash, thrombocytopenia
Antiphospholipid
Anti-Scl 70
Anti-Ro/SS-A
Anti-La/SS-B
Anti-Tm
Anti-Jo-1
Anti-DsDNA
Negative
2014, Suthar et al. (18)1At age 6 months, she had CHB, but she remained asymptomatic until 2 years old when she presented with left-sided hemiparesis with left upper motor neuron facial nerve palsy
MRI brain showed acute infarct in right putamen and internal capsule
She had a pacemaker placed with residual weakness on the side of the hemiparesis
SymptomaticNot testedCHB
2016, Kanda et al. (19)1Seizures developed at day 2. Physical examination was normal. Brain imaging showed infarction of the left middle cerebral artery territory. Patient fully recovered with no sequelaeSymptomaticANA
anti-Ro/SS-A
PositiveNone
Anti-La/SS-BNegative
2020, Wang et al. (20)1Seizure at 2 months. Brain MRI showed left middle cerebral artery stroke. Fully recovered by 3 years of ageSymptomaticAnti-Ro/SS-APositiveNone
2Developed global developmental delay at 6 monthsSymptomaticAnti-Ro/SS-APositiveCHB at 19 weeks of gestation
Anti-La/SS-BNegative
2022, Paswal et al. (21)1Phrenic nerve palsy evident on chest x-ray with elevated diaphragm and confirmed with nerve conduction studySymptomaticAnti-Ro/SS-A
Anti-La/SS-B
PositiveAnasarca, bradycardia, tachypnea, ascites, hepatomegaly, shock, CHB, thrombocytopenia, transaminitis
2023, Sun et al. (22)1Convulsions, EEG abnormalitiesSymptomaticRash, heart
2Extracerebral space enlargement (giant cranium)Rash, blood, liver, gastrointestinal, diabetic ketoacidosis
3Convulsions with subependymal hemorrhageSymptomaticBlood
4HydrocephalusNot clearGastrointestinal
5Subarachnoid hemorrhageNot clearBlood
6Subependymal hemorrhageNot clearRash, blood, liver, gastrointestinal, heart
7Convulsions, hydrocephalus, periventricular–intraventricular hemorrhage, extracerebral space enlargement (brain atrophy)SymptomaticRash, blood, liver, gastrointestinal
8Convulsions, hydrocephalus, subependymal hemorrhage, EEG abnormalitiesSymptomaticBlood, liver, heart
9Periventricular–intraventricular hemorrhage, extracerebral space enlargement (brain atrophy)Not clearRash, blood, liver
10Convulsions, hydrocephalus, subarachnoid hemorrhage, EEG abnormalitiesSymptomaticRash, blood, liver, gastrointestinal, heart, hypothyroidism

Literature review of neurologic involvement in NLE patients.

ANA, anti-nuclear antibody; CHB, congenital heart block; CT, computed tomography; DsDNA, double-stranded deoxyribonucleic acid; EEG, electroencephalogram; MRI, magnetic resonance imaging; NLE, neonatal lupus erythematosus; SS-A, anti-Sjogren's syndrome A; SS-B, anti-Sjogren's syndrome B; U1RNP, U1-ribonucleoprotein.

CHB is mostly seen with anti-Ro/SS-A and/or anti-La/SS-B. Only recently, CHB is being reported with anti-U1RNP with negative anti-Ro/SS-A and anti-La/SS-B (24). Similar to our case, a total of three patients who reported of having CHB with positive U1RNP (protein subtype not mentioned) and negative anti-Ro/SS-A and anti-La/SS-B but without any neurologic symptoms (24–26) were reported.

The current NLE recommendations for mothers with rheumatic diseases are targeted only for those with anti-Ro/SS-A and/or anti-La/SS-B antibodies. One of the recommendations is to use hydroxychloroquine during pregnancy (27). The other recommendation is early detection of CHB in the most vulnerable period of gestation. This is performed by measuring the mechanical PR interval with a weekly or bi-weekly Doppler fetal echocardiogram during 16–28 weeks of gestation (28).

It is important to rule out other possible causes or insults to diagnose NLE. In our case, GBS meningitis cannot be fully ruled out in the presence of a positive GBS result in the mother. In this admission, the mother received one dose of IV antibiotics, and the baby received a course of antibiotics. Our limitation here was the missing lumbar puncture. On the other hand, GBS meningitis was unlikely as it cannot explain the presence of heart block, and the patient remained well, afebrile with negative blood and urine cultures.

In summary, our patient had negative anti-Ro/SS-A and anti-La/SS-B and positive anti-U1RNP-70kD, presented with a seizure episode, and was found to have an incomplete heart block. The mother with SLE did not receive surveillance during pregnancy as the current guidelines are tailored for mothers with anti-Ro/SS-A and anti-La/SS-B. It is important to consider testing for U1RNP-70kD in newborns presenting with seizure and maternal SLE. In our case, the 70kD subtype of U1RNP is positive which may have a role in this unusual presentation. Further research looking at U1RNP and its subtypes in the context of NLE is needed to improve the care of mothers and babies with this antibody.

Statements

Data availability statement

The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding author.

Ethics statement

Written informed consent was obtained from the individual(s) and minor(s)’ legal guardian/next of kin, for the publication of any potentially identifiable images or data included in this article.

Author contributions

MA wrote the first draft of the manuscript. All authors contributed to manuscript revision. All authors contributed to the article and approved the submitted version.

Acknowledgments

We thank the baby and his family for their cooperation.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

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Summary

Keywords

neonatal lupus, systemic lupus erythematosus, heart block, seizure, case report

Citation

Alfalasi M, ElGhazali G, Fathalla W and Khawaja K (2023) Anti-U1RNP-70kD-positive case of neonatal lupus presenting with seizure and incomplete heart block: a case report and literature review. Front. Pediatr. 11:1239327. doi: 10.3389/fped.2023.1239327

Received

13 June 2023

Accepted

04 August 2023

Published

23 August 2023

Volume

11 - 2023

Edited by

Lovro Lamot, University of Zagreb, Croatia

Reviewed by

Mikhail Kostik, Saint Petersburg State Pediatric Medical University, Russia Andrea Trombetta, IRCCS Local Health Authority of Reggio Emilia, Italy

Updates

Copyright

*Correspondence: Khulood Khawaja

Disclaimer

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

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