Neonatal lupus erythematosus in Japan: a review of the literature

Neonatal Gut Mycobiome: Immunity, Diversity of Fungal Strains, and Individual and Non-Individual Factors

The human gastrointestinal ecosystem, or microbiome (comprising the total bacterial genome in an environment), plays a crucial role in influencing host physiology, immune function, metabolism, and the gut-brain axis. While bacteria, fungi, viruses, and archaea are all present in the gastrointestinal ecosystem, research on the human microbiome has predominantly focused on the bacterial component. The colonization of the human intestine by microbes during the first two years of life significantly impacts subsequent composition and diversity, influencing immune system development and long-term health. Early-life exposure to pathogens is crucial for establishing immunological memory and acquired immunity. Factors such as maternal health habits, delivery mode, and breastfeeding duration contribute to gut dysbiosis. Despite fungi's critical role in health, particularly for vulnerable newborns, research on the gut mycobiome in infants and children remains limited. Understanding early-life factors shaping the gut mycobiome and its interactions with other microbial communities is a significant research challenge. This review explores potential factors influencing the gut mycobiome, microbial kingdom interactions, and their connections to health outcomes from childhood to adulthood. We identify gaps in current knowledge and propose future research directions in this complex field.

Neonatal lupus erythematosus as a rare trigger of gastrointestinal involvement in neonates

Cutaneous and cardiac involvement in neonatal lupus erythematosus (NLE) has been extensively studied; however, gastrointestinal system involvement (GSI) remains unexplored. This study aimed to investigate the clinical features of GSI in patients with NLE with a particular focus on feeding intolerance (FI) and diarrhea. We conducted a retrospective analysis of the clinical data of patients diagnosed with NLE at the Children's Hospital of Soochow University between 2011 and 2022. In this study, of 39 patients diagnosed with NLE, 27 presented with GSI. 9 patients who presented with FI or diarrhea as the primary manifestation were positive for anti-SSA antibody, and 5 were dual positive for anti-SSA and anti-SSB antibodies. Among the mothers of the NLE patients with GSI, 18 had systemic lupus erythematosus, 3 had Sjogren's syndrome, 2 had mixed connective tissue disease, and one each had autoantibody abnormalities and photosensitivity symptoms; 4 mothers denied having any autoimmune disease. In this study, 69.23% of patients with NLE exhibited GSI, which was linked to hypocomplementemia and anti-SSA antibodies. Thus, clinicians should remain vigilant for NLE in neonates, particularly when accompanied with rash and other organ dysfunction and when the high-risk factors of FI and diarrhea have been excluded.

Maternal immune factors involved in the prevention or facilitation of neonatal bacterial infections

Newborns, whether born prematurely or at term, have a fully formed but naive immune system that must adapt to the extra-uterine environment to prevent infections. Maternal immunity, transmitted through the placenta and breast milk, protects newborns against infections, primarily via immunoglobulins (IgG and IgA) and certain maternal immune cells also known as microchimeric cells. Recently, it also appeared that the maternal gut microbiota played a vital role in neonatal immune maturation via microbial compounds impacting immune development and the establishment of immune tolerance. In this context, maternal vaccination is a powerful tool to enhance even more maternal and neonatal health. It involves the transfer of vaccine-induced antibodies to protect both mother and child from infectious diseases. In this work we review the state of the art on maternal immune factors involved in the prevention of neonatal bacterial infections, with particular emphasis on the role of maternal vaccination in protecting neonates against bacterial disease.

Clinical Features, Autoantibodies, and Outcome of Neonatal Lupus Erythematosus

Objectives: To explore the clinical features, autoantibodies, and outcome of neonatal lupus erythematosus (NLE). Methods: We retrospectively reviewed all NLE cases from January 2012 to May 2019 that occurred in our department. Results: Cutaneous, cardiac, hematologic, and hepatobiliary manifestations were found in 36.7%, 56.7%, 56.7%, and 30.0% of cases, respectively. The presence of anti-SSA antibodies was correlated with cardiac presentation (p = .026) and the presence of anti-SSB antibodies was associated with cutaneous lesions (p = .015). During the follow-up, one patient with a third-degree atrioventricular block died, and a third-degree AV block persists in a child without a pacemaker at 4-years of age. No other manifestations of NLE were observed after the age of 12 months. Conclusions: Anti-SSA and anti-SSB are associated with cardiac and cutaneous manifestations in NLE. Most children with NLE have excellent outcomes with symptom resolution by one year. Complete congenital heart block may persist.

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.

Lupus Heart Disease Modeling with Combination of Induced Pluripotent Stem Cell-Derived Cardiomyocytes and Lupus Patient Serum

Background and Objectives

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease mainly affecting young women of childbearing age. SLE affects the skin, joints, muscles, kidneys, lungs, and heart. Cardiovascular complications are common causes of death in patients with SLE. However, the complexity of the cardiovascular system and the rarity of SLE make it difficult to investigate these morbidities. Patient-derived induced pluripotent stem cells (iPSCs) serve as a novel tool for drug screening and pathophysiological studies in the absence of patient samples.

Methods and Results

We differentiated CMs from HC- and SLE-iPSCs using 2D culture platforms. SLE-CMs showed decreased proliferation and increased levels of fibrosis and hypertrophy marker expression; however, HC-and SLE-monolayer CMs reacted differently to SLE serum treatment. HC-iPSCs were also differentiated into CMs using 3D spheroid culture and anti-Ro autoantibody was treated along with SLE serum. 3D-HC-CMs generated more mature CMs compared to the CMs generated using 2D culture. The treatment of anti-Ro autoantibody rapidly increased the gene expression of fibrosis, hypertrophy, and apoptosis markers, and altered the calcium signaling in the CMs.

Conclusions

iPSC derived cardiomyocytes with patient-derived serum, and anti-Ro antibody treatment could serve in effective autoimmune disease modeling including SLE. We believe that the present study might briefly provide possibilities on the application of a combination of patient-derived materials and iPSCs in disease modeling of autoimmune diseases.

Neonatal Outcomes in Pregnant Women with Systemic Lupus Erythematosus: A 13-Year Experience in Southern Thailand

OBJECTIVES

The purpose of the study was to determine the clinical features of NLE and to compare the neonatal outcomes between newborns born to pregnant women with SLE and healthy pregnant women.

METHODS

We conducted a retrospective cohort analysis between 2007 and 2019 in a tertiary referral hospital in Thailand. A total of 118 pregnant women with SLE with 132 neonates compared with 264 randomly selected healthy pregnant women.

RESULTS

The median (interquartile range) gestational age and birth weight of 132 neonates born to women with SLE were 37 (35-38) weeks and 2687 g (2045-3160 g), respectively. The clinical features of NLE infants were hemolytic anemia (8%), thrombocytopenia (2.7%) and hyperbilirubinemia (5.3%). There was no neonate with a congenital complete heart block or skin lesion. Moreover, logistic regression analysis found that neonates born to women with SLE increased the risk of preterm birth [odd ratio (OR) 8.87, 95% confidence interval (95% CI) 4.32-18.21, p < 0.001], low birth weight (OR 10.35, 95% CI 5.08-21.08, p < 0.001), birth asphyxia (OR 2.91, 95% CI 1.26-6.73, p = 0.011) and NICU admission (OR 4.26, 95% CI 2.44-7.42, p < 0.001). SLE disease activity and corticosteroid and azathioprine usage were associated with preterm delivery in pregnant women with SLE.

CONCLUSION

The major clinical features of NLE patients were hematologic and hepatobiliary abnormalities in our study. Pregnancies with SLE dramatically increased the risk of preterm delivery and neonatal complications.

LAY SUMMARY

Neonatal lupus erythematosus (NLE) is the consequence of the transplacental passage of autoantibodies to newborns during pregnancy. The clinical features of NLE infants in our study were hemolytic anemia (8%), thrombocytopenia (2.7%) and hyperbilirubinemia (5.3%). There was no neonate with a congenital complete heart block or skin lesion. We also compared the neonatal outcomes between 118 pregnant women with SLE and 264 randomly selected healthy pregnant women. Our study found that the neonates born to women with SLE increased the risk of preterm birth, low birth weight, birth asphyxia and NICU admission. Moreover, SLE disease activity and corticosteroid and azathioprine usage were associated with preterm delivery in pregnant women with SLE.

Ethnicity and Neonatal Lupus Erythematosus Manifestations Risk in a Large Multiethnic Cohort

OBJECTIVE

To evaluate the association between ethnicity and neonatal lupus erythematosus (NLE), as well as specific NLE manifestations in a large multiethnic population.

METHODS

We conducted a cohort study of the children (≤ 1 yr of age) seen in the NLE clinic at The Hospital for Sick Children (SickKids), between January 2011 and April 2019. The cohort was divided into European, non-European, and mixed European-non-European groups according to parent-reported child's ethnicity (Canada Census categories). Outcomes were NLE and specific NLE manifestations (cardiac, cutaneous, cytopenias, transaminitis, and macrocephaly). The frequency of NLE and specific manifestations were compared between ethnic groups (Fisher exact test). We tested the association between ethnicity and (1) NLE risk, and (2) specific NLE manifestations with logistic regression models, including covariates for child's sex, maternal rheumatic disease status during pregnancy, and maternal use of antimalarials during pregnancy (multiple comparisons threshold P < 0.008).

RESULTS

We included 324 children born to 270 anti-Ro antibody-positive mothers. Median age at first visit was 1.8 (IQR 1.4-2.3) months, and median follow-up time was 12 (IQR 2-24) months. The majority was non-European (48%), with 34% European, and 18% mixed European-non-European. There was no significant association between non-European ethnicity (OR 1.18, 95% CI 0.71-1.94, P = 0.51), mixed European-non-European ethnicity (OR 1.13, 95% CI 0.59-2.16, P = 0.70), and NLE risk compared with European ethnicity. We also did not find an association between ethnicity and specific NLE manifestations in univariate or multivariable-adjusted models.

CONCLUSION

In a large multiethnic cohort, there was no association between a child's ethnicity and NLE risk or specific NLE manifestations.

Current Insights in Cutaneous Lupus Erythematosus Immunopathogenesis

Cutaneous Lupus Erythematosus (CLE) is a clinically diverse group of autoimmune skin diseases with shared histological features of interface dermatitis and autoantibodies deposited at the dermal-epidermal junction. Various genetic and environmental triggers of CLE promote infiltration of T cells, B cells, neutrophils, antigen presenting cells, and NK cells into lesional skin. In this mini-review, we will discuss the clinical features of CLE, insights into CLE immunopathogenesis, and novel treatment approaches.

Geoepidemiology and clinical characteristics of neonatal lupus erythematosus: a systematic literature review of individual patients’ data

Background/aim

 Neonatal lupus erythematosus (NLE) is an autoimmune syndrome caused by transplacental transmission of maternal autoantibodies, often with devastating consequences. The objective of this systematic literature review was to analyze the demographic data, geoepidemiology, clinical, and serological characteristics associated with NLE.

Materials and methods

 We performed a systematic literature search of the Pubmed database covering the period from 1976 to August 2015, using the MeSH terms “neonatal lupus” or “congenital heart block”. To be included in the study, articles of any type (original articles, case series, and case reports) had to report on infants with NLE on an individualized (i.e. patient-by-patient) basis. 

Results

A total of 198 studies were included in the review, reporting on a total of 755 NLE patients. The most frequently reported clinical manifestations of NLE were congenital heart block (CHB, 65.2%), cutaneous lupus (33.1%), and cytopenias (15.5%). We found differences in NLE characteristics based on study geographical origin, with CHB being much more frequent in patients of European or American descent (49.4% and 35%, respectively), while reports originating from Asia reported a higher prevalence of skin involvement (45.2%). Most CHB cases (72.9%) were diagnosed between the 18th and 26th week of gestation.

Conclusions

 Phenotypic differences of NLE depending on race and country may reflect true pathophysiologic differences or methodologic discrepancies. While maternal autoimmune disease is not a prerequisite for the development of NLE, the existence of a truly “immunonegative” CHB is questionable. 

Histopathology of Cutaneous Inflammatory Disorders in Children

Inflammatory dermatoses encompass a variety of histologic patterns that affect different portions of the skin. In spongiotic, psoriasiform, lichenoid, pityriasiform, and blistering disorders, there are predominately epidermal and junctional activities with variable superficial dermal inflammation. Hypersensitivity reactions can show either epidermal or mostly dermal changes depending on whether the exposure of the exogenous allergen occurs through an external or internal route, respectively. Exceptions include erythema multiforme and Stevens-Johnson syndrome/toxic epidermal necrolysis, where the etiology is often due to infection or ingested medications, but the histologic features are almost exclusively confined to the epidermis and dermoepidermal junction. Autoimmune disorders are unique in that lesions typically incorporate a mixture of epidermal and dermal inflammatory patterns with periadnexal inflammation, while the vast majority of vasculitis/vasculopathy and alopecia have changes limited to only the vessels and hair follicles, respectively. It is critical to recognize that a relatively limited number of histologic patterns are seen in a large array of clinical entities. Therefore, clinicopathologic correlation and careful examination of histologic details are of the utmost importance when evaluating skin biopsies for inflammatory disorders.

Maternal antibodies and developing blood-brain barrier

We briefly review the protective role of maternal antibodies during fetal development and at early postnatal stages. We describe antibody delivery to fetuses, particularly in the context of the developing blood-brain barrier (BBB), and present the essential concepts regarding the adult BBB, together with existing information on the prenatal developing BBB. We focus on maternal antibody transfer to the developing brain and the consequences of the presence of pathogenic antibodies at early stages of brain development on subsequent brain dysfunction.

A 3-Day-Old Girl Referred From Her Pediatrician for Oral Ulcerations

A 3-day-old girl was referred from her pediatrician for oral ulcerations. The patient was otherwise well appearing and afebrile. Her prenatal and antenatal courses were unremarkable, except for a failed routine hearing screen. The patient's examination was notable for several yellowish ulcers on erythematous bases located on her anterior tonsillar pillars. The patient also had a right coloboma and a II/VI systolic ejection murmur. Laboratory analyses revealed a traumatic lumbar puncture with 182 000 red blood cells and 808 white blood cells, as well as a complete blood count that showed thrombocytopenia and leukocytosis. During the patient's hospitalization, she developed a new facial rash. Her physical examination findings, along with her diagnostic evaluation and hospital course, ultimately led to 2 surprising diagnoses elaborated on in this case discussion.

IgG Autoantibodies Induced by T. cruzi During Pregnancy: Correlation with Gravidity Complications and Early Outcome Assessment of the Newborns

Objective The aim of the present research was to evaluate the correlation of vertically transmitted IgG antibodies induced by T. cruzi and newborn early outcome assessment, mainly birth weight and gestational age. Methods We performed a cross-sectional study with 183 pregnant women (64 with asymptomatic Chagas disease) and their newborns. Both were subjected to complete clinical examination. Peripheral parasitemia was assessed in mother and neonates by parasite detection through microscopic examination of the buffycoat from mother's peripheral and cord blood. Antibodies induced by T. cruzi, such as anti-FRA, anti-B13, anti-p2β and anti-T. cruzi were assessed by immunoassay. Birth weight, general condition evaluation by APGAR Score and gestational age by Capurro Score, were determined in newborns. Results The rate of stillbirth background and pregnancy-induced hypertension were higher in patients with Chagas disease (p = 0.01 and p = 0.02, respectively). Parasitemia was detectable in 17 mothers and 4 newborns. The newborns of mothers with detectable parasitemia presented decreased gestational age (p = 0.006) and body weight (p = 0.04). Mostly all the mothers with Chagas disease and all their newborns have positive values of antibodies induced by T. cruzi; however, only anti-p2β showed to be related to the presence of complication during pregnancy (OR 2.35, p = 0.036), and to low birth weight (OR 1.55, p = 0.02). Conclusions Low birth weight and decreased postnatal estimation of maturity were related to detectable parasitemia in the mother. Also, vertical transmission of T. cruzi-induced autoantibodies might have clinical implication in newborns given the negative association between anti-p2β values and weight.

Autoantibodies in Neuropsychiatric Disorders

Little is known about the etiology of neuropsychiatric disorders. The identification of autoantibodies targeting the N-methyl-d-aspartate receptor (NMDA-R), which causes neurological and psychiatric symptoms, has reinvigorated the hypothesis that other patient subgroups may also suffer from an underlying autoimmune condition. In recent years, a wide range of neuropsychiatric diseases and autoantibodies targeting ion-channels or neuronal receptors including NMDA-R, voltage gated potassium channel complex (VGKC complex), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA-R), γ-aminobutyric acid receptor (GABA-R) and dopamine receptor (DR) were studied and conflicting reports have been published regarding the seroprevalence of these autoantibodies. A clear causative role of autoantibodies on psychiatric symptoms has as yet only been shown for the NMDA-R. Several other autoantibodies have been related to the presence of certain symptoms and antibody effector mechanisms have been proposed. However, extensive clinical studies with large multicenter efforts to standardize diagnostic procedures for autoimmune etiology and animal studies are needed to confirm the pathogenicity of these autoantibodies. In this review, we discuss the current knowledge of neuronal autoantibodies in the major neuropsychiatric disorders: psychotic, major depression, autism spectrum, obsessive-compulsive and attention-deficit/hyperactivity disorders.

Isolated anti-Ro/SSA thrombocytopenia: a rare feature of neonatal lupus

We report a rare case of isolated thrombocytopenia related to anti-Ro/SSA antibodies. The mother was followed for unlabeled familial thrombocytopenia. The mother had positive anti-Ro/SSA antibodies. She was asymptomatic without skin lesions or other criteria neither of systemic lupus erythematosus nor other connective tissue disease. Pregnancy was uneventful. The postnatal examination was normal. On the first day of life, blood cells count showed thrombocytopenia at 40 x 10⁹/L. Within the second day of life, platelet level dropped to 20 x 10⁹/L. The management of thrombocytopenia included platelet transfusion and human immunoglobulin infusion. On the fifth day of life, there has been a drop in platelet count to 10 x 10⁹/L requiring renewed platelet transfusion and human immunoglobulin infusion. On the 10^th of life platelets rate was stable around 60 x 10⁹/L. The infant had no evidence of cardiac, dermatologic or hepatobilary involvement initially or throughout follow up.

Neonatal lupus erythematosus: a review of 123 cases in China

AIM

To analyze the clinical features, outcomes and prognosis of neonatal lupus erythematosus (NLE) in China.

METHOD

We reviewed 12 NLE cases at the Peking Union Medical College Hospital and compared the data with 111 cases reported in China between 1990 and 2014. The Chinese medical journal search engines used in this study were Wanfang.data and Science China.

RESULTS

No gender dominance in NLE incidence was found. Cutaneous lesions were present in more than 96% of patients, while cardiac, hematological and hepatobiliary manifestations were seen in 12.61%, 45.53% and 17.89% of cases, respectively. Congenital heart block (CHB) tended to be more persistent, with two cases showing CHB for 1 year and three cases persisting for 7-10 years. In this study more than 90% of mothers were anti-Sjögren's syndrome A positive, and 65.04% were asymptomatic prior to the pregnancy.

CONCLUSION

These results indicate that clinicians, especially dermatologists, in China should improve their recognition of this disease to avoid misdiagnosis, and more attention should be paid to the follow-up of NLE patients and their asymptomatic mothers.

Anti-SSA antibodies are present in immunoglobulin preparations

BACKGROUND

Anti-SSA autoantibodies are among the most frequently detected autoantibodies and have traditionally been associated with Sjögren's syndrome (SjS) and systemic lupus erythematosus. The unexpected finding of anti-SSA antibodies in a patient with common variable immunodeficiency disorder (CVID) treated with intravenous immunoglobulin (IVIG), who developed discoid lupus erythematosus, prompted us to investigate the presence of anti-SSA antibodies in IVIG preparations. Since anti-SSA antibodies may be present in apparently healthy individuals without overt autoimmune features, IVIG preparations may also contain anti-SSA antibodies.

STUDY DESIGN AND METHODS

IVIG consists of polyclonal immunoglobulin G isolated from the plasma of more than 1000 blood donors. Several IVIG batches from different suppliers and serum samples of patients receiving these IVIG products were tested for the presence of anti-nuclear antibodies (ANAs) and extractable nuclear antibodies (ENAs). In addition, we tested several plasma pools for the presence of anti-SSA and subsequent serum samples of individual donors.

RESULTS

Several CVID-patients receiving IVIG tested positive for ANA and anti-SSA. The IVIG products administered also contained clearly detectable concentrations of these antibodies. The frequency of apparently healthy blood donors with anti-SSA positivity was 0.69% and one of 1894 donors (0.05%) showed a very high titer of anti-SSA of more than 10,000 U/mL.

CONCLUSION

Anti-SSA is present in IVIG products and in blood donors without clinical symptoms. IVIG replacement can interfere with ANA and ENA serology by passive transfer of autoantibodies. We hypothesize that such autoantibodies may be causally related to disease manifestations in some recipients.

Clinical and pathological roles of Ro/SSA autoantibody system

Anti-Ro/SSA antibodies are among the most frequently detected autoantibodies against extractable nuclear antigens and have been associated with systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS). Although the presence of these autoantibodies is one of the criteria for the diagnosis and classification of SS, they are also sometimes seen in other systemic autoimmune diseases. In the last few decades, the knowledge of the prevalence of anti-Ro/SSA antibodies in various autoimmune diseases and symptoms has been expanded, and the clinical importance of these antibodies is increasing. Nonetheless, the pathological role of the antibodies is still poorly understood. In this paper, we summarize the milestones of the anti-Ro/SSA autoantibody system and provide new insights into the association between the autoantibodies and the pathogenesis of autoimmune diseases.

Neonatal autoimmune diseases: a critical review

Neonatal autoimmune diseases are distinctly rare. Most neonatal autoimmune diseases result from the transplacental transfer of maternal antibodies directed against fetal or neonatal antigens in various tissues. In neonatal lupus, the heart seems to be particularly susceptible. Primary autoimmunity in newborns, with the exception of familial autoinflammatory diseases, is virtually non-existent. The pathophysiologic basis for the development of neonatal autoimmunity is not entirely clear, but differences in the neonatal immune system compared with the adult immune system, as well as unique characteristics of target antigens in the newborn period may be important factors. Neonatal lupus is the most common presentation of autoimmunity in the newborn. But the characteristics defining neonatal lupus are not well defined and the presentation of neonatal lupus differs from that of classical lupus. Other neonatal autoimmune diseases involving the interaction between maternal antibodies and fetal/neonatal antigens include neonatal anti-phospholipid syndrome, Behcet's disease, neonatal autoimmune thyroid disease, neonatal polymyositis and dermatomyositis, neonatal scleroderma and neonatal type I diabetes mellitus. While autoantibodies have been detected in patients with neonatal autoimmune disease, the pathogenic role of autoantibodies has not been well defined. Other mechanisms may play a role in the development of neonatal autoimmunity, including fetal/maternal microchimerism and aberrant apoptosis of fetal cells. The autoinflammatory syndromes are a completely different category, but are also included in discussion of neonatal autoimmune diseases. The autoinflammatory syndromes include the cryopyrin associated periodic syndromes (CAPS) - familial cold autoinflammatory syndrome (FCAS), neonatal onset multisystem inflammatory disease (NOMID) and Muckle-Wells syndrome, which all share a common pathophysiologic mechanism.

IgG placental transfer in healthy and pathological pregnancies

Placental transfer of maternal IgG antibodies to the fetus is an important mechanism that provides protection to the infant while his/her humoral response is inefficient. IgG is the only antibody class that significantly crosses the human placenta. This crossing is mediated by FcRn expressed on syncytiotrophoblast cells. There is evidence that IgG transfer depends on the following: (i) maternal levels of total IgG and specific antibodies, (ii) gestational age, (iii) placental integrity, (iv) IgG subclass, and (v) nature of antigen, being more intense for thymus-dependent ones. These features represent the basis for maternal immunization strategies aimed at protecting newborns against neonatal and infantile infectious diseases. In some situations, such as mothers with primary immunodeficiencies, exogenous IgG acquired by intravenous immunoglobulin therapy crosses the placenta in similar patterns to endogenous immunoglobulins and may also protect the offspring from infections in early life. Inversely, harmful autoantibodies may cross the placenta and cause transitory autoimmune disease in the neonate.