Regulatory T-cell dysfunction and cutaneous exposure to Staphylococcus aureus underlie eczema in DOCK8 deficiency.

BACKGROUND: Dedicator of cytokinesis 8 (DOCK8)-deficient patients have severe eczema, elevated IgE, and eosinophilia, features of atopic dermatitis (AD). OBJECTIVE: We sought to understand the mechanisms of eczema in DOCK8 deficiency. METHODS: Skin biopsy samples were characterized by histology, immunofluorescence microscopy, and gene expression. Skin barrier function was measured by transepidermal water loss. Allergic skin inflammation was elicited in mice by epicutaneous sensitization with ovalbumin (OVA) or cutaneous application of Staphylococcus aureus. RESULTS: Skin lesions of DOCK8-deficient patients exhibited type 2 inflammation, and the patients' skin was colonized by Saureus, as in AD. Unlike in AD, DOCK8-deficient patients had a reduced FOXP3:CD4 ratio in their skin lesions, and their skin barrier function was intrinsically intact. Dock8-/- mice exhibited reduced numbers of cutaneous T regulatory (Treg) cells and a normal skin barrier. Dock8-/- and mice with an inducible Dock8 deletion in Treg cells exhibited increased allergic skin inflammation after epicutaneous sensitization with OVA. DOCK8 was shown to be important for Treg cell stability at sites of allergic inflammation and for the generation, survival, and suppressive activity of inducible Treg cells. Adoptive transfer of wild-type, but not DOCK8-deficient, OVA-specific, inducible Treg cells suppressed allergic inflammation in OVA-sensitized skin of Dock8-/- mice. These mice developed severe allergic skin inflammation and elevated serum IgE levels after topical exposure to Saureus. Both were attenuated after adoptive transfer of WT but not DOCK8-deficient Treg cells. CONCLUSION: Treg cell dysfunction increases susceptibility to allergic skin inflammation in DOCK8 deficiency and synergizes with cutaneous exposure to Saureus to drive eczema in DOCK8 deficiency.

Clinical, immunological, molecular and therapeutic findings in monogenic immune dysregulation diseases: Middle East and North Africa registry.

Monogenic immune dysregulation diseases (MIDD) are caused by defective immunotolerance. This study was designed to increase knowledge on the prevalence and spectrum of MIDDs, genetic patterns, and outcomes in Middle East and North Africa (MENA). MIDD patients from 11 MENA countries (Iran, Turkey, Kuwait, Oman, Algeria, Egypt, United Arab Emirates, Tunisia, Jordan, Qatar, and Azerbaijan) were retrospectively evaluated. 343 MIDD patients (58% males and 42% female) at a median (IQR) age of 101 (42-192) months were enrolled. The most common defective genes were LRBA (23.9%), LYST (8.2%), and RAB27A (7.9%). The most prevalent initial and overall manifestations were infections (32.2% and 75.1%), autoimmunity (18.6% and 41%), and organomegaly (13.3% and 53.8%), respectively. Treatments included immunoglobulin replacement therapy (53%), hematopoietic stem cell transplantation (HSCT) (14.3%), immunosuppressives (36.7%), and surgery (3.5%). Twenty-nine (59.2%) patients survived HSCT. Along with infectious complications, autoimmunity and organomegaly may be the initial or predominant manifestations of MIDD.

Profound differences in IgE and IgG recognition of micro-arrayed allergens in hyper-IgE syndromes.

BACKGROUND: The specificities of IgE and IgG for allergen molecules in patients with inborn errors of immunity (IEI) have not been investigated in detail. OBJECTIVE: To study IgE and IgG antibody specificities in patients with defined hyper-IgE syndromes (HIES) using a comprehensive panel of allergen molecules. METHODS: We used chips containing micro-arrayed allergen molecules to analyze allergen-specific IgE and IgG levels in sera from two groups of HIES patients: Autosomal recessive mutations in phosphoglucomutase-3 (PGM3); Autosomal dominant negative mutations of STAT3 (STAT3); and age-matched subjects with allergic sensitizations. Assays with rat basophil leukemia cells transfected with human FcεRI were performed to study the biological relevance of IgE sensitizations. RESULTS: Median total IgE levels were significantly lower in the sensitized control group (212.9 kU/L) as compared to PGM3 (5042 kU/L) and STAT3 patients (2561 kU/L). However, PGM3 patients had significantly higher allergen-specific IgE levels and were sensitized to a larger number of allergen molecules as compared to STAT3 patients. Biological relevance of IgE sensitization was confirmed for PGM3 patients by basophil activation testing. PGM3 patients showed significantly lower cumulative allergen-specific IgG responses in particular to milk and egg allergens as compared to STAT3 patients and sensitized controls whereas total IgG levels were comparable to STAT3 patients and significantly higher than in controls. CONCLUSION: The analysis with multiple micro-arrayed allergen molecules reveals profound differences of allergen-specific IgE and IgG recognition in PGM3 and STAT3 patients which may be useful for classification of IEI and clinical characterization of patients.

In silico comparative study of SARS-CoV-2 proteins and antigenic proteins in BCG, OPV, MMR and other vaccines: evidence of a possible putative protective effect.

BACKGROUND: Coronavirus Disease 2019 (COVID-19) is a viral pandemic disease that may induce severe pneumonia in humans. In this paper, we investigated the putative implication of 12 vaccines, including BCG, OPV and MMR in the protection against COVID-19. Sequences of the main antigenic proteins in the investigated vaccines and SARS-CoV-2 proteins were compared to identify similar patterns. The immunogenic effect of identified segments was, then, assessed using a combination of structural and antigenicity prediction tools. RESULTS: A total of 14 highly similar segments were identified in the investigated vaccines. Structural and antigenicity prediction analysis showed that, among the identified patterns, three segments in Hepatitis B, Tetanus, and Measles proteins presented antigenic properties that can induce putative protective effect against COVID-19. CONCLUSIONS: Our results suggest a possible protective effect of HBV, Tetanus and Measles vaccines against COVID-19, which may explain the variation of the disease severity among regions.

Genetic Approaches for Definitive Diagnosis of Agammaglobulinemia in Consanguineous Families.

Autosomal recessive agammaglobulinemia (ARA) is a primary immunodeficiency characterized by absent peripheral B cells, severe hypogammaglobulinemia, and absent BTK gene mutations. In ARA, mutations occur in genes encoding the pre-B cell receptor (pre-BCR) or downstream signaling proteins. In this work, we used candidate gene and whole-exome sequencing to investigate the molecular basis of ARA in 6 patients from 4 consanguineous North-African families. Sanger sequencing of candidate genes encoding the pre-BCR components (ΙGΗΜ, CD79A, CD79B, IGLL1, and VPREB1) was initially performed and determined the genetic defect in five patients. Two novel mutations in IGHM (p.Val378Alafs*1 and p.Ile184Serfs*21) were identified in three patients from two unrelated kindred and a novel nonsense mutation was identified in CD79A (p.Trp66*) in two siblings from a third kindred. Whole-exome sequencing (WES) was performed on the sixth patient who harbored a homozygous stop mutation at position 407 in the RAG2 gene (p.Glu407*). We concluded that conventional gene sequencing, especially when multiple genes are involved in the defect as is the case in ARA, is costly and time-consuming, resulting in delayed diagnosis that contributes to increased morbidity and mortality. In addition, it fails to identify the involvement of novel and unsuspected gene defects when the phenotype of the patients is atypical. WES has the potential to provide a rapid and more accurate genetic diagnosis in ARA, which is crucial for the treatment of the patients.

A Founder Effect of c.257 + 2T > C Mutation in NCF2 Gene Underlies Severe Chronic Granulomatous Disease in Eleven Patients.

Chronic granulomatous disease (CGD) is the prototypic functional neutrophil disorder caused by genetic defects in one of the five genes encoding the superoxide-generating nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase subunits of phagocytes. Mutations causing the most prevalent form of CGD in western populations are located in the X-linked-CYBB gene. The four remaining autosomal recessive (AR) forms collectively account for one-third of CGD cases. We investigated the clinical and molecular features of eleven patients with CGD from 6 consanguineous families, originating from contiguous regions in the west of Tunisia. The patients' clinical phenotype is characterized by a high incidence of mycobacterial infections. Five out of the eleven patients died despite treatment arguing in favor of a severe clinical form of CGD. These findings correlated with the absence of functional p67phox protein as well as the absence of residual reactive oxygen intermediates (ROI) production. Genetic analysis showed the presence, in all patients, of a unique mutation (c.257 + 2T > C) in NCF2 gene predicted to affect RNA splicing. Segregating analysis using nine polymorphic markers overlapping the NCF2 gene revealed a common haplotype spanning 4.1 Mb. The founder event responsible for this mutation was estimated to have arisen approximately 175 years ago. These findings will facilitate the implementation of preventive approaches through genetic counseling in affected consanguineous families.

X-Linked Agammagobulinemia in a Large Series of North African Patients: Frequency, Clinical Features and Novel BTK Mutations.

PURPOSE: X-linked agammagobulinemia (XLA) is a primary immunodeficiency caused by Bruton's tyrosine kinase (BTK) gene defect. XLA patients have absent or reduced number of peripheral B cells and a profound deficiency in all immunoglobulin isotypes. This multicenter study reports the clinical, immunological and molecular features of Bruton's disease in 40 North African male patients. METHODS: Fifty male out of 63 (male and female) patients diagnosed with serum agammaglobulinemia and non detectable to less than 2% peripheral B cells were enrolled. The search for BTK gene mutations was performed for all of them by genomic DNA amplification and Sanger sequencing. RESULTS: We identified 33 different mutations in the BTK gene in 40 patients including 12 missense mutations, 6 nonsense mutations, 6 splice-site mutations, 5 frameshift, 2 large deletions, one complex mutation and one in-frame deletion. Seventeen of these mutations are novel. This large series shows a lower frequency of XLA among male patients from North Africa with agammaglobulinemia and absent to low B cells compared with other international studies (63.5% vs. 85%). No strong evidence for genotype-phenotype correlation was observed. CONCLUSIONS: This study adds to other reports from highly consanguineous North African populations, showing lower frequency of X-linked forms as compared to AR forms of the same primary immunodeficiency. Furthermore, a large number of novel BTK mutations were identified and could further help identify carriers for genetic counseling.

Novel and recurrent AID mutations underlie prevalent autosomal recessive form of HIGM in consanguineous patients.

Immunoglobulin class switch recombination deficiencies (Ig-CSR-D) are characterized by normal or elevated serum IgM level and absence of IgG, IgA, and IgE. Most reported cases are due to X-linked CD40L deficiency. Activation-induced cytidine deaminase deficiency is the most frequent autosomal recessive form, whereas CD40 deficiency is more rare. Herein, we present the first North African study on hyper IgM (HIGM) syndrome including 16 Tunisian patients. Phenotypic and genetic studies allowed us to determine their molecular basis. Three CD40LG mutations have been identified including two novels (c.348_351dup and c.782_*2del) and one already reported mutation (g.6182G>A). No mutation has been found in another patient despite the lack of CD40L expression. Interestingly, three AICDA mutations have been identified in 11 patients. Two mutations were novel (c.91T>C and c.389A>C found in one and five patients respectively), and one previously reported splicing mutation (c.156+1T>G) was found in five patients. Only one CD40-deficient patient, bearing a novel mutation (c.109T>G), has been identified. Thus, unlike previous reports, AID deficiency is the most frequent underlying molecular basis (68%) of Ig-CSR-D in Tunisian patients. This finding and the presence of specific recurrent mutations are probably due to the critical role played by inbreeding in North African populations.

The extended clinical phenotype of 64 patients with dedicator of cytokinesis 8 deficiency.

BACKGROUND: Mutations in dedicator of cytokinesis 8 (DOCK8) cause a combined immunodeficiency (CID) also classified as autosomal recessive (AR) hyper-IgE syndrome (HIES). Recognizing patients with CID/HIES is of clinical importance because of the difference in prognosis and management. OBJECTIVES: We sought to define the clinical features that distinguish DOCK8 deficiency from other forms of HIES and CIDs, study the mutational spectrum of DOCK8 deficiency, and report on the frequency of specific clinical findings. METHODS: Eighty-two patients from 60 families with CID and the phenotype of AR-HIES with (64 patients) and without (18 patients) DOCK8 mutations were studied. Support vector machines were used to compare clinical data from 35 patients with DOCK8 deficiency with those from 10 patients with AR-HIES without a DOCK8 mutation and 64 patients with signal transducer and activator of transcription 3 (STAT3) mutations. RESULTS: DOCK8-deficient patients had median IgE levels of 5201 IU, high eosinophil levels of usually at least 800/µL (92% of patients), and low IgM levels (62%). About 20% of patients were lymphopenic, mainly because of low CD4(+) and CD8(+) T-cell counts. Fewer than half of the patients tested produced normal specific antibody responses to recall antigens. Bacterial (84%), viral (78%), and fungal (70%) infections were frequently observed. Skin abscesses (60%) and allergies (73%) were common clinical problems. In contrast to STAT3 deficiency, there were few pneumatoceles, bone fractures, and teething problems. Mortality was high (34%). A combination of 5 clinical features was helpful in distinguishing patients with DOCK8 mutations from those with STAT3 mutations. CONCLUSIONS: DOCK8 deficiency is likely in patients with severe viral infections, allergies, and/or low IgM levels who have a diagnosis of HIES plus hypereosinophilia and upper respiratory tract infections in the absence of parenchymal lung abnormalities, retained primary teeth, and minimal trauma fractures.

Hypomorphic homozygous mutations in phosphoglucomutase 3 (PGM3) impair immunity and increase serum IgE levels.

BACKGROUND: Recurrent bacterial and fungal infections, eczema, and increased serum IgE levels characterize patients with the hyper-IgE syndrome (HIES). Known genetic causes for HIES are mutations in signal transducer and activator of transcription 3 (STAT3) and dedicator of cytokinesis 8 (DOCK8), which are involved in signal transduction pathways. However, glycosylation defects have not been described in patients with HIES. One crucial enzyme in the glycosylation pathway is phosphoglucomutase 3 (PGM3), which catalyzes a key step in the synthesis of uridine diphosphate N-acetylglucosamine, which is required for the biosynthesis of N-glycans. OBJECTIVE: We sought to elucidate the genetic cause in patients with HIES who do not carry mutations in STAT3 or DOCK8. METHODS: After establishing a linkage interval by means of SNPchip genotyping and homozygosity mapping in 2 families with HIES from Tunisia, mutational analysis was performed with selector-based, high-throughput sequencing. Protein expression was analyzed by means of Western blotting, and glycosylation was profiled by using mass spectrometry. RESULTS: Mutational analysis of candidate genes in an 11.9-Mb linkage region on chromosome 6 shared by 2 multiplex families identified 2 homozygous mutations in PGM3 that segregated with disease status and followed recessive inheritance. The mutations predict amino acid changes in PGM3 (p.Glu340del and p.Leu83Ser). A third homozygous mutation (p.Asp502Tyr) and the p.Leu83Ser variant were identified in 2 other affected families, respectively. These hypomorphic mutations have an effect on the biosynthetic reactions involving uridine diphosphate N-acetylglucosamine. Glycomic analysis revealed an aberrant glycosylation pattern in leukocytes demonstrated by a reduced level of tri-antennary and tetra-antennary N-glycans. T-cell proliferation and differentiation were impaired in patients. Most patients had developmental delay, and many had psychomotor retardation. CONCLUSION: Impairment of PGM3 function leads to a novel primary (inborn) error of development and immunity because biallelic hypomorphic mutations are associated with impaired glycosylation and a hyper-IgE-like phenotype.

Clinical features of Candidiasis in patients with inherited interleukin 12 receptor ß1 deficiency.

BACKGROUND: Interleukin 12Rß1 (IL-12Rß1)-deficient patients are prone to clinical disease caused by mycobacteria, Salmonella, and other intramacrophagic pathogens, probably because of impaired interleukin 12-dependent interferon γ production. About 25% of patients also display mucocutaneous candidiasis, probably owing to impaired interleukin 23-dependent interleukin 17 immunity. The clinical features and outcome of candidiasis in these patients have not been described before, to our knowledge. We report here the clinical signs of candidiasis in 35 patients with IL-12Rß1 deficiency. RESULTS: Most (n = 71) of the 76 episodes of candidiasis were mucocutaneous. Isolated oropharyngeal candidiasis (OPC) was the most common presentation (59 episodes, 34 patients) and was recurrent or persistent in 26 patients. Esophageal candidiasis (n = 7) was associated with proven OPC in 2 episodes, and cutaneous candidiasis (n = 2) with OPC in 1 patient, whereas isolated vulvovaginal candidiasis (VVC; n = 3) was not. Five episodes of proven invasive candidiasis were documented in 4 patients; 1 of these episodes was community acquired in the absence of any other comorbid condition. The first episode of candidiasis occurred earlier in life (median age±standard deviation, 1.5 ± 7.87 years) than infections with environmental mycobacteria (4.29 ± 11.9 years), Mycobacterium tuberculosis (4 ± 3.12 years), or Salmonella species (4.58 ± 4.17 years) or other rare infections (3 ± 11.67 years). Candidiasis was the first documented infection in 19 of the 35 patients, despite the vaccination of 10 of these 19 patients with live bacille Calmette-Guérin. CONCLUSIONS: Patients who are deficient in IL-12Rß1 may have candidiasis, usually mucocutaneous, which is frequently recurrent or persistent. Candidiasis may be the first clinical manifestation in these patients.

A 1,100-year-old founder effect mutation in IL12B gene is responsible for Mendelian susceptibility to mycobacterial disease in Tunisian patients.

Mendelian susceptibility to mycobacterial disease (MSMD) is a rare disorder predisposing apparently healthy individuals to infections caused by weakly virulent mycobacteria such as bacille Calmette-Guerin (BCG), environmental mycobacteria, and poorly virulent Salmonella strains. IL-12p40 deficiency is the first reported human disease due to a cytokine gene defect and is one of the deficiencies that cause MSMD. Nine mutant alleles only have been identified in the IL12B gene, and three of them are recurrent mutations due to a founder effect in specific populations. IL-12p40 deficiency has been identified especially in countries where consanguinity is high and where BCG vaccination at birth is universal. We investigated, in such settings, the clinical, cellular, and molecular features of six IL-12p40-deficient Tunisian patients having the same mutation in IL12B gene (c.298_305del). We found that this mutation is inherited as a common founder mutation arousing ~1,100 years ago. This finding facilitates the development of a preventive approach by genetic counseling and prenatal diagnosis especially in affected families.

Clinical, immunological and genetic findings of a large tunisian series of major histocompatibility complex class II deficiency patients.

INTRODUCTION: Major histocompatibility complex class II (MHC-II) expression deficiency is a combined primary immunodeficiency leading to the impairment of the cellular and humoral immune responses. A majority of affected patients belong to consanguineous families particularly from the Maghreb, where a founder effect for a highly frequent mutation (named c.338-25_338del26) in the RFXANK gene was reported. Herein, we report the largest single Maghrebian country series of MHC-II deficient patients. PATIENTS AND METHODS: In Tunisia, among 551 PIDs diagnosed from 1993 to 2011, 54 had an MHC-II deficiency. The clinical features and immunological investigations were retrospectively analyzed in 34 children of them belonging to 28 kindred. The genetic study included the c.338-25_338del26 screening by the amplification of the affected region using polymerase chain reaction (PCR) followed by direct sequencing. RESULTS: Consanguinity was present in 22 out of 28 families. Mean age at the first infection was 6.1 months. Chronic diarrhea with failure to thrive and pulmonary infections were the most common manifestations occurring in 26 and 28 patients respectively. The most specific laboratory findings were the defect of MHC-II (HLA-DR) expression in all patients. The c.338-25_338del26 mutation was identified in 25 of them. CONCLUSION: In Maghrebian settings, pediatricians should definitely consider this diagnosis in the presence of an early onset of severe and recurrent infections of the respiratory and intestinal tracts, particularly protracted diarrhea with a failure to thrive. The founder effect for the c.338-25_338del26 mutation in the RFXANK gene is also confirmed, facilitating prenatal diagnosis as a preventive approach in the Tunisian affected families with severe forms, particularly in the context of limited access to bone marrow transplantation.

The Middle East and North Africa Diagnosis and Management Guidelines for Inborn Errors of Immunity.

Human inborn errors of immunity (IEI) are a group of 485 distinct genetic disorders affecting children and adults. Signs and symptoms of IEI are heterogeneous, and accurate diagnosis can be challenging and depends on the available human expertise and laboratory resources. The Middle East and North Africa (MENA) region has an increased prevalence of IEI because of the high rate of consanguinity with a predominance of autosomal recessive disorders. This area also exhibits more severe disease phenotypes compared with other regions, probably due to the delay in diagnosis. The MENA-IEI registry network has designed protocols and guidelines for the diagnosis and treatment of IEI, taking into consideration the variable regional expertise and resources. These guidelines are primarily meant to improve the care of patients within the region, but can also be followed in other regions with similar patient populations.

Diagnostic challenge in a series of eleven patients with hyper IgE syndromes.

Hyper IgE syndromes (HIES) is a heterogeneous group of Inborn Errors of Immunity characterized by eczema, recurrent skin and lung infections associated with eosinophilia and elevated IgE levels. Autosomal dominant HIES caused by loss of function mutations in Signal transducer and activator of transcription 3 (STAT3) gene is the prototype of these disorders. Over the past two decades, advent in genetic testing allowed the identification of ten other etiologies of HIES. Although Dedicator of Cytokinesis 8 (DOCK8) deficiency is no more classified among HIES etiologies but as a combined immunodeficiency, this disease, characterized by severe viral infections, food allergies, autoimmunity, and increased risk of malignancies, shares some clinical features with STAT3 deficiency. The present study highlights the diagnostic challenge in eleven patients with the clinical phenotype of HIES in a resource-limited region. Candidate gene strategy supported by clinical features, laboratory findings and functional investigations allowed the identification of two heterozygous STAT3 mutations in five patients, and a bi-allelic DOCK8 mutation in one patient. Whole Exome Sequencing allowed to unmask atypical presentations of DOCK8 deficiency in two patients presenting with clinical features reminiscent of STAT3 deficiency. Our study underlies the importance of the differential diagnosis between STAT3 and DOCK8 deficiencies in order to improve diagnostic criteria and to propose appropriate therapeutic approaches. In addition, our findings emphasize the role of NGS in detecting mutations that induce overlapping phenotypes.

Case Report: FOXP3 Mutation in a Patient Presenting With ALPS.

ALPS and IPEX are two well-characterized inborn errors of immunity with immune dysregulation, considered as two master models of monogenic auto-immune diseases. Thus, with autoimmunity as their primary clinical manifestation, these two entities may show clinical overlap. Traditionally, immunological biomarkers are used to establish an accurate differential diagnosis. Herein, we describe a patient who presented with clinical features and biomarkers fulfilling the diagnostic criteria of ALPS. Severe apoptotic defect was also shown in the patient's cell lines and PHA-activated peripheral blood lymphocytes. Sanger sequencing of the FAS gene did not reveal any causal mutation. NGS screening revealed a novel deleterious variant located in the N terminal repressor domain of FOXP3 but no mutations in the FAS pathway-related genes. TEMRA cells (terminally differentiated effector memory cells re-expressing CD45RA) and PD1 expression were increased arguing in favor of T-cell exhaustion, which could be induced by unrestrained activation of T effector cells because of Treg deficiency. Moreover, defective FOXP3 observed in the patient could intrinsically induce increased proliferation and resistance to apoptosis in T effector cells. This observation expands the spectrum of FOXP3 deficiency and underscores the role of NGS in detecting mutations that induce overlapping phenotypes among inborn errors of immunity with immune dysregulation. In addition, these findings suggest a potential link between FOXP3 and FAS pathways.

Autoantibodies in patients with interleukin 12 receptor beta 1 deficiency.

OBJECTIVE: Interleukin 12 receptor beta 1 (IL-12Rß1) deficiency is a primary immunodeficiency that exposes affected individuals to an augmented risk of intracellular pathogen-mediated infections. The paradoxical presence of autoimmune manifestations in immune-deficient patients has been recognized, but the basis of this phenomenon is unclear, with the role of frequent infections being a possible trigger to break tolerance. Our study aimed to analyze extensively a profile of autoantibodies in a clinically well-defined case series of patients with IL-12Rß1 deficiency. METHODS: Eight patients with IL-12Rß1 deficiency referred to Children's Medical Center in Tunis, Tunisia, during 1995-2012 were enrolled in the study. Sixteen age- and gender-matched blood donors served as controls. Serum, liver-related autoantibodies immunoglobulin (Ig)G, IgM, IgA were tested by ELISA and by standard indirect immunofluorescence on Hep-2 cells. RESULTS: We found a significant prevalence of liver autoantibodies in the study group. Regarding primary biliary cholangitis (PBC), two of eight patients were positive for MIT3 autoantibodies, both confirmed by immunofluorescence, and one patient was positive for PBC-specific antinuclear antibodies, sp100. Moreover, two patients had significantly increased gamma-glutamyltransferase levels and one had IgM levels twice the upper limit of normal. Intriguingly two patients were positive for anti-actin antibodies; a typical feature of autoimmune hepatitis type 1, along with a significant increase in IgG levels. CONCLUSIONS: This is the first report of a serological analysis in patients with an IL-12Rß1 deficiency. Despite the difficulty in interpreting the role of the IL-12, the evidence of liver-specific autoantibodies confirms the importance its signal in liver autoimmunity.