Risk of autoimmune diseases in patients with RASopathies: systematic study of humoral and cellular immunity

BACKGROUND

Abnormalities of the immune system are rarely reported in patients affected by RASopathies. Aim of the current study was to investigate the prevalence of immune system dysfunction in a cohort of patients affected by RASopathies.

STUDY DESIGN

A group of 69 patients was enrolled: 60 at the Federico II University, Naples, 7 at University Magna Graecia of Catanzaro, 2 at "Scuola Medica Salernitana", Salerno. An age- and sex-matched control group was also enrolled. Autoimmune disorders were investigated according to international consensus criteria. Immune framework was also evaluated by immunoglobulin levels, CD3, CD4, CD8, CD19, CD56 lymphocyte subpopulations, autoantibodies levels and panel of inflammatory molecules, in both patients and controls.

RESULTS

Frequent upper respiratory tract infections were recorded in 2 patients; pneumonia, psoriasis and alopecia in single patients. Low IgA levels were detected in 8/44 patients (18.18%), low CD8 T cells in 13/35 patients (37.14%). Anti-tg and anti-TPO antibodies were detected in 3/24 patients (12.5%), anti r-TSH in 2 cases (8.33%), all in euthyroidism. Serum IgA and CD8 levels were significantly lower in patients than in controls (p 0.00685; p 0.000656 respectively). All tested patients showed increased inflammatory molecules compared to controls. These findings may anticipate the detection of overt autoimmune disease.

CONCLUSIONS

Patients affected by RASopathies are at risk to develop autoimmune disorders. Routine screening for autoimmunity is recommended in patients with RASopathy.

Widening the Neuroimaging Features of Adenosine Deaminase 2 Deficiency

Adenosine deaminase 2 deficiency (OMIM #615688) is an autosomal recessive disorder characterized by a wide clinical spectrum, including small- and medium-sized vessel vasculopathies, but data focusing on the associated neuroimaging features are still scarce in the literature. Here, we describe the clinical neuroimaging features of 12 patients with genetically proven adenosine deaminase 2 deficiency (6 males; median age at disease onset, 1.3 years; median age at genetic diagnosis, 15.5 years). Our findings expand the neuroimaging phenotype of this condition demonstrating, in addition to multiple, recurrent brain lacunar ischemic and/or hemorrhagic strokes, spinal infarcts, and intracranial aneurysms, also cerebral microbleeds and a peculiar, likely inflammatory, perivascular tissue in the basal and peripontine cisterns. Together with early clinical onset, positive family history, inflammatory flares and systemic abnormalities, these findings should raise the suspicion of adenosine deaminase 2 deficiency, thus prompting genetic evaluation and institution of tumor necrosis factor inhibitors, with a potential great impact on neurologic outcome.

OP0273 ADHERENCE TO COLCHICINE TREATMENT AND COLCHICINE RESISTANCE IN A MULTICENTRIC FMF NATIONAL COHORT

Background:

Colchicine is the standard treatment for Familiar Mediterranean Fever (FMF), however about 5% of patients experience colchicine resistance. There is no standard definition of colchicine resistance. Recently a panel of experts elaborated a new definition based on a Delphi consensus approach.

Objectives:

We aim to describe main features of the disease and clinical outcome of a cohort of FMF patients with particular interest on the colchicine resistance and tolerability according to the definitions proposed by the recent consensus.

Methods:

Since November 2009, 425 Italian pediatric and adult FMF patients (pts) from 13 centers were enrolled in a national longitudinal cohort study, using the international EUROFEVER registry. Demographic, genetic and clinical data, including response to treatment, were analyzed. Supplementary information on health related quality of life and treatment adherence was also collected by a specific questionnaire.

Results:

Complete information were available in 341 pts (189 M and 152 F, 211 children and 120 adults). The median age at disease onset was 5.0 years (1 m-59 y); the mean diagnostic delay was 8.7 y (range 0-61 y). The median age at enrollment was 12.1 y (range 3 m - 82 y). The MEFV genotype was the following: 103 (30.2%) pts carried biallelic pathogenic variants; 59 (17.3%) one pathogenic variants and one VOUS /LB variant; 27 (7.9%) had biallelic VOUS/LB variants; 97 (28.45%) were heterozygous for pathogenic variants; 30 (8.8%) were heterozygous for VOUS/LB, 25 (7.33%) were genetically negative.

Colchicine treatment was used in 280 pts; during treatment, biologic treatment (anti-IL1) in 22 pts. 61 pts received NSAID or steroid on demand.

We analyzed the behavior of the pts treated with colchicine according to the statements on colchicine resistance/intolerance defined by Ozen et al (1) (Table 1).

Table 1.Adherence62% displayed a total adherence (> 90% of prescription); 10.8% a good adherence (50-89% of prescriptions); 1.9% poor adherence (< 50% of prescriptions); 0.9% no adherenceDose adjustment criteria/ Recommended maximum colchicine doseMean colchicine dose:Pts <5 years: 0.57mg/de (std. dev. 0.18)5-10 year: 0.77mg/die (std. dev. 0.23)10-18 years: 1.1mg/die (std. dev. 0.39)Adults: 1.16 mg/die (std. dev. 0.37)Pts with a dose inferior to the minimum recommended dose5-10 years: 2.5%10-18 years: 15%Adults: 4%Resistance to ColchicineResistance was be defined as persistence of fever attacks, despite optimal treatment. 41.6% pts had a complete disease control32.8% Pts had < 1 episode/month for 3 months25.5% had ≥1 episode/month for 3 monthsInclusion of secondary amyloidosis in the definition of colchicine resistance5 adult pts (1.5%) displayed amyloidosisColchicine intolerance11 pts (3.2%) withdraw colchicine because of drug intolerancePatient quality of life and patient-reported outcomes20.7% of pts experience fatigue or chronic pain, 16.9% limitations in daily activities, and 16.9% have lost school/work days.

Conclusion:

Almost 58% of FMF pts display disease activity despite colchicine treatment. The treatment is generally under-dosed, especially in children. The adherence and the compliance to the treatment is generally good.

References:

[1]Ozen S et all. Recommendation on colchicine dosing and definition of colchicine resistance/intolerance in the management of FMF. Pediatric Rheumatology, 2019.

Acknowledgments:

This research was financial supported by Novartis AG

Disclosure of Interests:

Romina Gallizzi: None declared, Marta Bustaffa: None declared, Francesca Mazza: None declared, Diana Sutera: None declared, Giovanna Fabio: None declared, Laura Obici: None declared, Maria Alessio: None declared, Donato Rigante: None declared, Luca Cantarini: None declared, Antonella Insalaco: None declared, Marco Cattalini: None declared, Maria Cristina Maggio: None declared, Gabriele Simonini: None declared, Alma Nunzia Olivieri: None declared, Serena Pastore: None declared, Maddalena Lancieri: None declared, Nicolino Ruperto Grant/research support from: Bristol-Myers Squibb, Eli Lily, F Hoffmann-La Roche, GlaxoSmithKline, Janssen, Novartis, Pfizer, Sobi (paid to institution), Consultant of: Ablynx, AbbVie, AstraZeneca-Medimmune, Biogen, Boehringer Ingelheim, Bristol-Myers Squibb, Eli Lily, EMD Serono, GlaxoSmithKline, Hoffmann-La Roche, Janssen, Merck, Novartis, Pfizer, R-Pharma, Sanofi, Servier, Sinergie, Sobi, Takeda, Speakers bureau: Ablynx, AbbVie, AstraZeneca-Medimmune, Biogen, Boehringer Ingelheim, Bristol-Myers Squibb, Eli Lily, EMD Serono, GlaxoSmithKline, Hoffmann-La Roche, Janssen, Merck, Novartis, Pfizer, R-Pharma, Sanofi, Servier, Sinergie, Sobi, Takeda, Marco Gattorno Consultant of: Sobi, Novartis, Speakers bureau: Sobi, Novartis

Generation and Characterization of a Murine Monoclonal Antibody Specific for the Human T1-Cd5 Molecule

Murine monoclonal antibodies (MoAbs) have found widespread applications in the characterization of the molecular and functional features of lymphocyte differentiation antigens. The present paper summarizes the results of our work dealing with the production and selection of a murine MoAb recognizing a molecule expressed during the whole differentiative life of T lymphocytes. The MoAb CB01 resulted to be specific for an apparently unique epitope of the T-cell specific membrane glycoprotein T1-CD5.

In vivo microglia activation in very early dementia with Lewy bodies, comparison with Parkinson's disease

BACKGROUND

Reactive microgliosis, hallmark of neuroinflammation, may contribute to neuronal degeneration, as shown in several neurodegenerative diseases. We in vivo evaluated microglia activation in early dementia with Lewy bodies, still not reported, and compared with early Parkinson's disease, to assess possible differential pathological patterns.

METHODS

We measured the [(11)C]-PK11195 binding potentials with Positron Emission Tomography, using a simplified reference tissue model, as marker of microglia activation, and cerebral spinal fluid protein carbonylation levels, as marker of oxidative stress. Six dementia with Lewy bodies and 6 Parkinson's disease patients within a year from the onset, and eleven healthy controls were included. Clinical diagnosis was confirmed at a 4-year follow-up.

RESULTS

In dementia with Lewy bodies as well as in Parkinson's disease, we found significant (p < 0.001) [(11)C]-PK11195 binding potential increases in the substantia nigra and putamen. Patients with Lewy bodies dementia had extensive additional microglia activation in several associative cortices. This was evident also at a single subject level. Significant increase of Cerebral Spinal Fluid protein carbonylation was shown in both patients' groups.

CONCLUSIONS

[(11)C]-PK11195 Positron Emission Tomography imaging revealed neuroinflammation in dementia with Lewy bodies and Parkinson's disease, mirroring, even at a single subject level, the common and the different topographical distribution of neuropathological changes, yet in the earliest stages of the disease process. Focusing on those events that characterize parkinsonisms and Parkinson's disease may be the key to further advancing the understanding of pathogenesis and to taking these mechanisms forward as a means of defining targets for neuroprotection.

Preliminary evidence that etanercept may reduce radiographic progression in juvenile idiopathic arthritis

OBJECTIVE

To investigate the rate of radiographic progression, as measured with the carpo-metacarpal ratio (Poznanski score), during etanercept (ETN) therapy in children with polyarticular juvenile idiopathic arthritis (JIA).

METHODS

Patients included in the Italian ETN registry who had a standard radiograph of both hands and wrists in the posteroanterior view made at start of treatment and after 1 year were included in the study. The clinical response was assessed by means of the ACR Pediatric definition of improvement. Radiographic progression was determined by calculating the change in the Poznanski score between the baseline and the 1-year radiographs.

RESULTS

A total of 40 patients were studied. The frequency of ACR pediatric 30, 50, and 70 response at 1 year was 77%, 72%, and 50%, respectively. The median change in the Poznanski score between baseline and 1 year was + 0.3 units, meaning that, on average, patients experienced improvement in radiographic progression.

CONCLUSION

Our pilot study provides evidence that ETN is potentially capable of reducing the progression of radiographic joint damage in JIA. This finding deserves confirmation in a controlled trial.

Clinical and genetic characterization of Italian patients affected by CINCA syndrome

OBJECTIVE

We report the experience of the Italian Registry of patients affected by chronic infantile neurological, cutaneous, articular (CINCA) syndrome. The clinical and genetic features of 12 unrelated Italian patients with CINCA syndrome are described, focusing on the possible influence of the presence of CIAS1/cryopyrin mutations on the phenotype of the disease and on its prognosis.

METHODS

The clinical features of 12 Italian CINCA patients were evaluated. Genomic DNA of the patients was sequenced using specific primers for CIAS1 and ASC genes.

RESULTS

Our patients shared typical CINCA characteristics and, sometimes, remarkable perinatal events, peculiar of CIAS1-mutated patients. Seven patients carried CIAS1 missense mutation, localized within the nucleotide binding domain of cryopyrin. Four previously described mutations and three new heterozygous CIAS1 missense mutations were identified. ASC gene, encoding for a direct interactor of cryopyrin, was not mutated in Italian CINCA patients. Finally, we reported the efficacy and safety of anti-IL1 therapy (Anakinra) in seven patients with a particularly severe CINCA phenotype.

CONCLUSION

Despite some common signs-used as syndrome hallmarks-we observed a high variability in symptoms, genetic results and outcomes in Italian CINCA patients. In contrast with other authors, we cannot find out any correlation between mutations in CIAS1 and CINCA severity, but we underlined the concomitance of perinatal events and mental retardation only in CIAS1 mutated subjects. Finally, we confirmed the efficacy of Anakinra treatment, both in CIAS1-mutated and non-mutated patients.

ZAP-70 is expressed by normal and malignant human B-cell subsets of different maturational stage

ZAP-70 tyrosine kinase is involved in signalling pathways following T-cell receptor stimulation and was originally described only in T cells and natural killer cells. ZAP-70 expression has been reported in normal mouse B lineage cells and in human malignant B lymphocytes, mainly in chronic lymphocytic leukemia (CLL) where it correlates with clinical outcome. We analyzed several B-cell lines and ex vivo malignant B cells, ranging from acute lymphoblastic leukemia to multiple myeloma and reflecting different stages of B-cell differentiation, and they showed ZAP-70 expression regardless their maturation stage. We then analyzed by Western blot and flow cytometry different human normal B-lymphocyte subpopulations: naïve, germinal center and memory B cells from tonsils, CD19+ CD5+ cells from cord blood and CD19+ lymphocytes from peripheral blood. All expressed ZAP-70 protein, though at different levels depending on their differentiation, activation and tissue localization. In addition, ZAP-70 expression levels could be modulated following stimulation via the B-cell receptor. These findings implicate a potential role of ZAP-70 in the signalling pathway of B lymphocytes at different maturational stages, indicate that ZAP-70 expression is not a CLL-specific feature among B-cell malignancies and suggest that the absence of ZAP-70 rather than its presence should be considered abnormal for malignant B lymphocytes.

Cytoadherence of Plasmodium falciparum-infected erythrocytes is mediated by a redox-dependent conformational fraction of CD36

The adherence of Plasmodium falciparum-infected RBC (IRBC) to postcapillary venular endothelium is an important determinant of the pathogenesis of severe malaria complications. Cytoadherence of IRBC to endothelial cells involves specific receptor/ligand interactions. The glycoprotein CD36 expressed on endothelial cells is the major receptor involved in this interaction. Treatment of CD36-expressing cells with reducing agents, such as DTT and N-acetylcysteine, was followed by CD36 conformational change monitorable by the appearance of the Mo91 mAb epitope. Only a fraction of the surface expressed CD36 molecules became Mo91 positive, suggesting the presence of two subpopulations of molecules with different sensitivities to reduction. The Mo91 epitope has been localized on a peptide (residues 260-279) of the C-terminal, cysteine-rich region of CD36. Treatment with reducing agents inhibited the CD36-dependent cytoadherence of IRBC to CD36-expressing cells and dissolved pre-existent CD36-mediated IRBC/CD36-expressing cell aggregates. CD36 reduction did not impair the functionality of CD36, since the reactivity of other anti-CD36 mAbs as well as the binding of oxidized low density lipoprotein, a CD36 ligand, were maintained. The modifications induced by reduction were reversible. After 14 h CD36 was reoxidized, the cells did not express the Mo91 epitope, and cytoadherence to IRBC was restored. The results indicate that IRBCs bind only to a redox-modulated fraction of CD36 molecules expressed on the cell surface. The present data indicate the therapeutic potential of reducing agents, such as the nontoxic drug N-acetylcysteine, to prevent or treat malaria complications due to IRBC cytoadhesion.

The Italian version of the Childhood Health Assessment Questionnaire (CHAQ) and the Child Health Questionnaire (CHQ)

We report herein the results of the cross-cultural adaptation and validation into the Italian language of the parent's version of two health related quality of life instruments. The Childhood Health Assessment Questionnaire (CHAQ) is a disease specific health instrument that measures functional ability in daily living activities in children with juvenile idiopathic arthritis (JIA). The Child Health Questionnaire (CHQ) is a generic health instrument designed to capture the physical and psychosocial well-being of children independently from the underlying disease. The Italian CHAQ was already published in the literature and was therefore revalidated while the Italian CHQ was fully cross culturally adapted with 3 forward and 3 backward translations, and than validated. A total of 1,192 subjects were enrolled: 404 patients with JIA (16% systemic onset, 31% polyarticular onset, 21% extended oligoarticular subtype, and 32% persistent oligoarticular subtype) and 788 healthy children. The CHAQ clinically discriminated between healthy subjects and JIA patients, with the systemic, polyarticular and extended oligoarticular subtypes having a higher degree of disability, pain, and a lower overall well-being when compared to their healthy peers. Also the CHQ clinically discriminated between healthy subjects and JIA patients, with the systemic onset, polyarticular onset and extended oligoarticular subtypes having a lower physical and psychosocial well-being when compared to their healthy peers. In conclusion the Italian version of the CHAQ-CHQ are reliable, and valid tools for the functional, physical and psychosocial assessment of children with JIA.

Methionine 156 in the immunodominant domain of CD36 contributes to define the epitope recognized by the NL07 MoAb

CD36 is a membrane glycoprotein expressed by several cell types, and play a role as a receptor for different physiological and pathological ligands. An immunodominant domain of CD36 has been described in the amino acidic region 155-183, where many ligands and monoclonal antibodies (MoAbs) react. MoAbs against CD36 have proved useful in structural as well as functional studies. One of these antibodies, MoAb NL07, recognizes a conformational epitope that is acquired in the late steps of the CD36 maturation. The NL07 epitope appears to be functionally relevant and blocks CD36-mediated binding to red blood cells infected with the malaria parasite Plasmodium falciparum (IRBC). In this work a mutant COS-7 clone expressing NL07-negative CD36 molecules on the cell surface was investigated. In the mutant, the methionine in position 156 of the wild type CD36 sequence was replaced by a valine. It was determined that methionine 156 was essential for NL07 reactivity, mapping the NL07 epitope to the vicinity of the functionally important immunodominant domain (aa 155-183) of CD36. Although methionine 156 is located in this region, the CD36V156 mutated molecule was apparently functional and able to bind IRBC and oxidized LDL.

Simultaneous peripubertal onset of multireactive autoimmune diseases with an unusual long-lasting remission of type 1 diabetes mellitus

Although it is well known that patients with type 1 diabetes mellitus are susceptible to other autoimmune diseases, the simultaneous occurrence of clustered distinct autoimmune diseases is uncommon. We report a 16-year-old girl, previously diagnosed as having coeliac disease and IgA deficiency, who at 13 years of age developed a clustering of distinct autoimmune diseases, including type 1 diabetes mellitus, rheumatoid arthritis (RA) and euthyroid autoimmune thyroiditis, eventually resulting in a simultaneous long-term remission. The clinical picture was associated with a functional immunodeficiency characterized by a defect in proliferative responses to T cell predominant mitogens and a normal response to the B cell predominant mitogen. In addition, the T cell activation markers HLA-DR, IL-2 receptor and transferrin receptor) were not upregulated. The clinical course of this immunodeficiency paralleled the outcome of the autoimmune diseases. After the abrupt onset, spontaneous clinical remission of both diabetes mellitus and RA was observed. Insulin was first reduced in dose and then discontinued completely at 15 months, in the presence of normal C peptide secretion and normal metabolic control (HbA1c 5.8%). Anti-glutamate decarboxylase (GAD65) and anti-IA-2 antibodies remained persistently high. During the remission phase a normalization of the functional immune defect was observed. The gradual resolution of the multisystemic diseases as well as the normalization of immune function in our patient is unusual. This case may be of considerable value in furthering our knowledge of the immunological mechanisms implicated in these rare multireactive syndromes.

CD36 is a ditopic glycoprotein with the N-terminal domain implicated in intracellular transport

The CD36 receptor sequence predicts two hydrophobic domains located at the N- and C-termini of the protein, but there are conflicting reports as to whether the N-terminal uncleaved leader sequence functions as a transmembrane domain. To investigate the topology of CD36, we generated a panel of mutants lacking either one or both hydrophobic regions and analyzed their folding and transport in COS-7 cells. The N- and the C-terminal hydrophobic regions were both sufficient to anchor CD36 in the membrane, and a FLAG epitope inserted at the N-terminus was located intracellularly. These results indicate that CD36 adopts a ditopic configuration. Accordingly, neither N- nor C-terminal truncation mutants were secreted. Analysis with conformation-specific monoclonal antibodies showed that the N-terminal transmembrane domain truncated molecule was slowly transported through the exocytic pathway and largely accumulated intracellularly. Thus, dual membrane insertion dictates the correct topogenesis and seems to be necessary for efficient folding and intracellular transport.

CD36 folding revealed by conformational epitope expression is essential for cytoadherence of Plasmodium falciparum-infected red blood cells

CD36 is a membrane glycoprotein and a putative scavenger receptor expressed by several cell types. In capillary endothelial cells, it mediates the adherence of erythrocytes infected with Plasmodium falciparum. The CD36 sequence contains two hydrophobic domains located at the amino-and carboxyl-termini of the protein, but the topology of this protein and the functional significance of these domains are still not clearly defined. We generated soluble CD36-IgG chimeric molecules by fusion of the extracellular domains of CD36 with human immunoglobulin domains. The construct containing the N-terminal hydrophobic domain of CD36 was completely retained intracellularly as membrane-associated molecule, suggesting that the N-terminal hydrophobic domain of the CD36 is a real transmembrane domain and that CD36 has hairpin topology. A small amount of the CD36-IgG chimeric construct lacking both transmembrane domains escaped retention, was correctly processed, and accumulated in the extracellular medium as a soluble molecule. This CD36-IgG construct failed to bind Plasmodium falciparum-infected erythrocytes. Using monoclonal antibodies specific for either conformational or structural epitopes, we demonstrate that failure of this CD36-IgG construct to bind infected erythrocytes was due to incorrect folding of the soluble chimeric molecule.