Assessing the digenic model in rare disorders using population sequencing data.

An important fraction of patients with rare disorders remains with no clear genetic diagnostic, even after whole-exome or whole-genome sequencing, posing a difficulty in giving adequate treatment and genetic counseling. The analysis of genomic data in rare disorders mostly considers the presence of single gene variants in coding regions that follow a concrete monogenic mode of inheritance. A digenic inheritance, with variants in two functionally-related genes in the same individual, is a plausible alternative that might explain the genetic basis of the disease in some cases. In this case, digenic disease combinations should be absent or underrepresented in healthy individuals. We develop a framework to evaluate the significance of digenic combinations and test its statistical power in different scenarios. We suggest that this approach will be relevant with the advent of new sequencing efforts including hundreds of thousands of samples.

Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic syndrome (VEXAS syndrome) with prominent supraglottic larynx involvement: a case-based review.

Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic syndrome (VEXAS syndrome) is a recently described genetic disorder that gathers autoinflammatory symptoms and myeloid dysplasia. The first description was reported in 2020, and subsequently, a growing number of cases have been described worldwide. Herein, we describe a case of a 72-year-old male patient with VEXAS syndrome with p.Met41Val mutation of the UBA1 gene, prominent supraglottic larynx involvement, and costochondritis. To our knowledge, this is the first report of VEXAS syndrome in Colombia and South America. This disease could present features of relapsing polychondritis, polyarteritis nodosa, giant cell arteritis, and Sweet syndrome, associated with hematologic involvement, including cytopenias, myelodysplastic syndrome, or thromboembolic disease. Supraglottic larynx chondritis and costochondritis are atypical manifestations. These features were proposed previously to differentiate relapsing polychondritis from VEXAS syndrome but are not entirely reliable like in the case described. A diagnosis of VEXAS should be considered in male patients with incomplete or complete features of the previously described conditions, refractory to treatment, requiring high-dose glucocorticoids, and associated progressive hematologic abnormalities. Key Points • VEXAS syndrome is a recently described genetic (somatic mutations in UBA1 gene) disorder that gathers autoinflammatory and hematologic manifestations. • VEXAS syndrome should be considered in male patients with incomplete or complete features of relapsing polychondritis, polyarteritis nodosa, giant cell arteritis, and Sweet syndrome, refractory to treatment, associated with hematologic involvement, including cytopenias, myelodysplastic syndrome, or thromboembolic disease. • Glucocorticoids ameliorate symptoms effectively. However, other treatment options are limited due to a lack of evidence. Traditional immunosuppressants and biological therapy have been used empirically with limited efficacy and a transient effect. Bone marrow transplant offers a curative approach, but it has high morbidity and mortality.

Long-Term Responders After Autologous Stem Cell Transplantation in Multiple Myeloma.

Introduction: Multiple myeloma (MM) is considered an incurable hematological neoplasm. For transplant-eligible patients, initial treatment includes an induction phase followed by an autologous stem cell transplantation (ASCT). Despite the introduction of several drugs in the past years, relapses still occur. Nevertheless, some patients achieve sustained responses after successful induction treatment and ASCT. Methods: We retrospectively evaluated all patients diagnosed with MM in our institution who underwent induction treatment and ASCT between 1990 and 2015. The subset of patients who achieved a sustained response (any degree) for 5 or more years after ASCT without further treatment or signs of progression were distinguished as "long-term responders" (LTRs). In the non-LTR group, a cohort referred to as "prolonged responders" (PLRs) showed sustained response of at least 5 years after ASCT but eventually relapsed. We collected and analyzed clinical and laboratory data. Results: Two hundred and fifty patients were diagnosed with MM and received induction treatment and ASCT at our institution in the study period. Among them, 54 (21.6%) patients met the criteria for LTR. Some diagnostic features such as a younger age, female gender, ECOG performance status of 0, lower International Staging System (ISS) stage, lower bone marrow plasma cell infiltration, and lower serum levels of calcium, C-reactive protein, and lactate dehydrogenase (LDH) were found to be more prevalent in LTR. Female gender, an ECOG performance status of 0, a localized Durie-Salmon stage, an ISS of I-II, the absence of bone disease, and an LDH within normal range were also predictive of longer progression-free survival (PFS) and overall survival (OS) in the whole cohort. The depth of the response achieved after induction and ASCT as well as the administration of an IMID-based maintenance regimen may play a role in the differences observed on PFS between cohorts. A detectable M-protein with a monoclonal gammopathy of undetermined significance (MGUS)-like behavior was detected in one-third of LTR after ASCT. Although relapses continue to occur in patients who achieve a 5-year treatment-free period after ASCT, a plateau is observed in the survival curves at approximately 21 years of follow-up.

Excellent response to secukinumab in an infant with severe generalized pustular psoriasis.

Generalized pustular psoriasis (GPP) represents the rarest form of psoriasis, which may be potentially fatal. In the last decade, (likely) pathogenic variants in the IL36RN, CARD14 and AP1S3 genes have been associated with monogenic GPP forms. Despite these advances, the genetic basis of most patients with GPP remains unidentified. Treatment of GPP patients is often difficult, with no consensus about the best available options to date. We report herein an infant with severe GPP in whom the disease started at the age of 2 months. Genetic investigations identified a heterozygous pathogenic variant in the IL36RN gene associated with a heterozygous variant of uncertain significance in the CARD14 gene. After previous treatment failures with acitretin, cyclosporin and anakinra, treatment with the interleukin-17 antagonist secukinumab resulted in a dramatic and prompt positive response that persisted at 12-month follow up. According to our experience, we believe secukinumab can be an effective and safe treatment for pediatric patients with GPP even before 1 year of age.

Executive Summary of the Consensus Document on the Diagnosis and Management of Patients with Primary Immunodeficiencies.

Primary immunodeficiencies (PIDs) are rare, undiagnosed and potentially fatal diseases. Clinical manifestations of PID can be fatal or leave sequelae that worsen the quality of life of patients. Traditionally, the treatment of PIDs has been largely supportive, with the exception of bone marrow transplantation and, more recently, gene therapy. The discovering of new affected pathways, the development of new molecules and biologics, and the increasing understanding of the molecular basis of these disorders have created opportunities in PIDs therapy. This document aims to review current knowledge and to provide recommendations about the diagnosis and clinical management of adults and children with PIDs based on the available scientific evidence taking in to account current practice and future challenges. A systematic review was conducted, and evidence levels based on the available literature are given for each recommendation where available.

Executive Summary of the Consensus Document on the Diagnosis and Management of Patients with Primary Immunodeficiencies.

Primary immunodeficiencies (PIDs) are rare, undiagnosed and potentially fatal diseases. Clinical manifestations of PID can be fatal or leave sequelae that worsen the quality of life of patients. Traditionally, the treatment of PIDs has been largely supportive, with the exception of bone marrow transplantation and, more recently, gene therapy. The discovering of new affected pathways, the development of new molecules and biologics, and the increasing understanding of the molecular basis of these disorders have created opportunities in PIDs therapy. This document aims to review current knowledge and to provide recommendations about the diagnosis and clinical management of adults and children with PIDs based on the available scientific evidence taking in to account current practice and future challenges. A systematic review was conducted, and evidence levels based on the available literature are given for each recommendation where available.

Classification criteria for autoinflammatory recurrent fevers.

BACKGROUND: Different diagnostic and classification criteria are available for hereditary recurrent fevers (HRF)-familial Mediterranean fever (FMF), tumour necrosis factor receptor-associated periodic fever syndrome (TRAPS), mevalonate kinase deficiency (MKD) and cryopyrin-associated periodic syndromes (CAPS)-and for the non-hereditary, periodic fever, aphthosis, pharyngitis and adenitis (PFAPA). We aimed to develop and validate new evidence-based classification criteria for HRF/PFAPA. METHODS: Step 1: selection of clinical, laboratory and genetic candidate variables; step 2: classification of 360 random patients from the Eurofever Registry by a panel of 25 clinicians and 8 geneticists blinded to patients' diagnosis (consensus ≥80%); step 3: statistical analysis for the selection of the best candidate classification criteria; step 4: nominal group technique consensus conference with 33 panellists for the discussion and selection of the final classification criteria; step 5: cross-sectional validation of the novel criteria. RESULTS: The panellists achieved consensus to classify 281 of 360 (78%) patients (32 CAPS, 36 FMF, 56 MKD, 37 PFAPA, 39 TRAPS, 81 undefined recurrent fever). Consensus was reached for two sets of criteria for each HRF, one including genetic and clinical variables, the other with clinical variables only, plus new criteria for PFAPA. The four HRF criteria demonstrated sensitivity of 0.94-1 and specificity of 0.95-1; for PFAPA, criteria sensitivity and specificity were 0.97 and 0.93, respectively. Validation of these criteria in an independent data set of 1018 patients shows a high accuracy (from 0.81 to 0.98). CONCLUSION: Eurofever proposes a novel set of validated classification criteria for HRF and PFAPA with high sensitivity and specificity.

Evaluating the Genetics of Common Variable Immunodeficiency: Monogenetic Model and Beyond.

Common variable immunodeficiency (CVID) is the most frequent symptomatic primary immunodeficiency characterized by recurrent infections, hypogammaglobulinemia and poor response to vaccines. Its diagnosis is made based on clinical and immunological criteria, after exclusion of other diseases that can cause similar phenotypes. Currently, less than 20% of cases of CVID have a known underlying genetic cause. We have analyzed whole-exome sequencing and copy number variants data of 36 children and adolescents diagnosed with CVID and healthy relatives to estimate the proportion of monogenic cases. We have replicated an association of CVID to p.C104R in TNFRSF13B and reported the second case of homozygous patient to date. Our results also identify five causative genetic variants in LRBA, CTLA4, NFKB1, and PIK3R1, as well as other very likely causative variants in PRKCD, MAPK8, or DOCK8 among others. We experimentally validate the effect of the LRBA stop-gain mutation which abolishes protein production and downregulates the expression of CTLA4, and of the frameshift indel in CTLA4 producing expression downregulation of the protein. Our results indicate a monogenic origin of at least 15-24% of the CVID cases included in the study. The proportion of monogenic patients seems to be lower in CVID than in other PID that have also been analyzed by whole exome or targeted gene panels sequencing. Regardless of the exact proportion of CVID monogenic cases, other genetic models have to be considered for CVID. We propose that because of its prevalence and other features as intermediate penetrancies and phenotypic variation within families, CVID could fit with other more complex genetic scenarios. In particular, in this work, we explore the possibility of CVID being originated by an oligogenic model with the presence of heterozygous mutations in interacting proteins or by the accumulation of detrimental variants in particular immunological pathways, as well as perform association tests to detect association with rare genetic functional variation in the CVID cohort compared to healthy controls.

Acute generalized exanthematous pustulosis and polyarthritis associated with a novel CARD14 mutation.

Acute generalised exanthematous pustulosis (AGEP) is a rare toxicoderma characterised by an acute onset rash, with many sterile pustules on the surface, high fever and increased acute phase reactants. We report the case of a patient who presented to the dermatology department with an AGEP and polyarthritis, in which a novel CARD14 mutation was identified. The pathophysiological mechanism of AGEP remains unclear, although mutations in the IL36RN gene have been identified in a small subset of AGEP patients. Similarly, mutations in the CARD14 gene have been linked to pustular types of psoriasis and familiar cases of pityriasis rubra pilaris; however, there are no reports associating mutations in the CARD14 gene with AGEP.

mTOR intersects antibody-inducing signals from TACI in marginal zone B cells.

Mechanistic target of rapamycin (mTOR) enhances immunity in addition to orchestrating metabolism. Here we show that mTOR coordinates immunometabolic reconfiguration of marginal zone (MZ) B cells, a pre-activated lymphocyte subset that mounts antibody responses to T-cell-independent antigens through a Toll-like receptor (TLR)-amplified pathway involving transmembrane activator and CAML interactor (TACI). This receptor interacts with mTOR via the TLR adapter MyD88. The resulting mTOR activation instigates MZ B-cell proliferation, immunoglobulin G (IgG) class switching, and plasmablast differentiation through a rapamycin-sensitive pathway that integrates metabolic and antibody-inducing transcription programs, including NF-κB. Disruption of TACI-mTOR interaction by rapamycin, truncation of the MyD88-binding domain of TACI, or B-cell-conditional mTOR deficiency interrupts TACI signaling via NF-κB and cooperation with TLRs, thereby hampering IgG production to T-cell-independent antigens but not B-cell survival. Thus, mTOR drives innate-like antibody responses by linking proximal TACI signaling events with distal immunometabolic transcription programs.

Novel evidences of atypical manifestations in cryopyrin-associated periodic syndromes.

OBJECTIVES: Cryopyrin-associated periodic syndromes (CAPS) usually start during infancy as an urticarial-like rash and a marked acute phase response, with additional manifestations appearing during its evolution. The aim of this study was to expand the clinical diversity of CAPS by the description of novel atypical features. METHODS: Clinical data were collected from patients' medical charts. Sanger sequencing analyzed NLRP3. Response to anti-IL-1 blockade was evaluated by clinical assessments and by measurements of laboratory parameters. RESULTS: Seventeen patients from two families (A and B), carrying the p.Ala439Thr and p.Arg260Trp NLRP3 mutations respectively, were enrolled. The disease was unexpectedly atypical in all members of Family A, with a 16-year-old asymptomatic carrier, and onset in adulthood associated with absence of skin lesions in four affected members. Surprisingly, one patient from each family suffered from severe haemorrhagic cystitis due to AA amyloidosis in the urinary bladder. Members of Family B displayed a classical phenotype, with two patients suffering from olfactive disorders. CONCLUSIONS: Our evidence suggests that CAPS may occasionally be presented as a late-onset, recurrent inflammatory disease without urticarial-like rash. In some patients, AA amyloidosis in strange locations like urinary bladder may complicate the clinical course. The response to IL-1 blockade in these atypical CAPS was similar to that described in classical forms. Consequently, we suggest that CAPS should be included in the differential diagnosis of adult patients with unexplained, recurrent inflammatory diseases, and once confirmed, the early initiation of anti-IL-1 blockade will probably prevent the development of life-threatening complications.

Newly Described Autoinflammatory Diseases in Pediatric Dermatology.

Specific gene mutations leading to dysregulation of innate immune response produce the expanding spectrum of monogenic autoinflammatory diseases (AIDs). They are characterized by seemingly unprovoked, recurrent episodes of systemic inflammation in which a myriad of manifestations usually affect skin. Novel genetic technologies have led to the discovery of new AIDs and phenotypes that were not previously clinically described. Consequently the number of AIDs is continuously growing and their recognition and the disclosure of their pathophysiology will prompt early diagnosis and targeted treatment of affected patients. The objective of the present work is to review those newly described AIDs with prominent dermatologic manifestations that may constitute a major criterion for their diagnosis.

Innate lymphoid cells integrate stromal and immunological signals to enhance antibody production by splenic marginal zone B cells.

Innate lymphoid cells (ILCs) regulate stromal cells, epithelial cells and cells of the immune system, but their effect on B cells remains unclear. Here we identified RORγt(+) ILCs near the marginal zone (MZ), a splenic compartment that contains innate-like B cells highly responsive to circulating T cell-independent (TI) antigens. Splenic ILCs established bidirectional crosstalk with MAdCAM-1(+) marginal reticular cells by providing tumor-necrosis factor (TNF) and lymphotoxin, and they stimulated MZ B cells via B cell-activation factor (BAFF), the ligand of the costimulatory receptor CD40 (CD40L) and the Notch ligand Delta-like 1 (DLL1). Splenic ILCs further helped MZ B cells and their plasma-cell progeny by coopting neutrophils through release of the cytokine GM-CSF. Consequently, depletion of ILCs impaired both pre- and post-immune TI antibody responses. Thus, ILCs integrate stromal and myeloid signals to orchestrate innate-like antibody production at the interface between the immune system and circulatory system.

B cell-helper neutrophils stimulate the diversification and production of immunoglobulin in the marginal zone of the spleen.

Neutrophils use immunoglobulins to clear antigen, but their role in immunoglobulin production is unknown. Here we identified neutrophils around the marginal zone (MZ) of the spleen, a B cell area specialized in T cell-independent immunoglobulin responses to circulating antigen. Neutrophils colonized peri-MZ areas after postnatal mucosal colonization by microbes and enhanced their B cell-helper function after receiving reprogramming signals, including interleukin 10 (IL-10), from splenic sinusoidal endothelial cells. Splenic neutrophils induced immunoglobulin class switching, somatic hypermutation and antibody production by activating MZ B cells through a mechanism that involved the cytokines BAFF, APRIL and IL-21. Neutropenic patients had fewer and hypomutated MZ B cells and a lower abundance of preimmune immunoglobulins to T cell-independent antigens, which indicates that neutrophils generate an innate layer of antimicrobial immunoglobulin defense by interacting with MZ B cells.

Multiple myeloma in serologic complete remission after autologous stem cell transplantation: impact of bone marrow plasma cell assessment by conventional morphology on disease progression.

The current definition of complete remission (CR) in multiple myeloma (MM) requires a negative serum and urine immunofixation (IFE) and <5% bone marrow plasma cells (BMPCs). The aim of this study was to determine the value of BMPCs count by standard microscopic evaluation in patients with MM in serologic CR after autologous stem cell transplantation (ASCT). Thirty-five patients with a median follow-up after ASCT of 7.3 years were studied. The percentage of BMPCs was an independent predictor of progression in multivariate model (hazard ratio 2.02, P = .009). Patients with >1.5% BMPCs (median: 0.8%) after ASCT had an increased risk of progression (P = .016) and a trend toward a shorter survival (P = .195). In conclusion, conventional morphology of bone marrow is a useful and rapid tool as a first step to assess the residual tumor mass in patients with MM in CR after ASCT, and it constitutes a strong predictor for disease progression.