Eli Mansour

First Report of the Hyper-IgM Syndrome Registry of the Latin American Society for Immunodeficiencies: Novel Mutations, Unique Infections, and Outcomes

Hyper-IgM (HIGM) syndrome is a heterogeneous group of disorders characterized by normal or elevated serum IgM levels associated with absent or decreased IgG, IgA and IgE. Here we summarize data from the HIGM syndrome Registry of the Latin American Society for Immunodeficiencies (LASID). Of the 58 patients from 51 families reported to the registry with the clinical phenotype of HIGM syndrome, molecular defects were identified in 37 patients thus far. We retrospectively analyzed the clinical, immunological and molecular data from these 37 patients. CD40 ligand (CD40L) deficiency was found in 35 patients from 25 families and activation-induced cytidine deaminase (AID) deficiency in 2 unrelated patients. Five previously unreported mutations were identified in the CD40L gene (CD40LG). Respiratory tract infections, mainly pneumonia, were the most frequent clinical manifestation. Previously undescribed fungal and opportunistic infections were observed in CD40L-deficient patients but not in the two patients with AID deficiency. These include the first cases of pneumonia caused by Mycoplasma pneumoniae, Serratia marcescens or Aspergillus sp. and diarrhea caused by Microsporidium sp. or Isospora belli. Except for four CD40L-deficient patients who died from complications of presumptive central nervous system infections or sepsis, all patients reported in this study are alive. Four CD40L-deficient patients underwent successful bone marrow transplantation. This report characterizes the clinical and genetic spectrum of HIGM syndrome in Latin America and expands the understanding of the genotype and phenotype of this syndrome in tropical areas.

Leptin action in the thymus.

Leptin was first characterized as a hormone that plays a central role in the control of body adiposity. A number of studies later revealed several other functions for leptin, including the capacity to modulate immune system activity. Currently, leptin occupies an important position as a unifying mechanism integrating nutritional status and immune function. Here, we will review some of the actions of leptin in the immune system, with special attention to the functions it exerts in the thymus.

Fyn Mediates Leptin Actions in the Thymus of Rodents

Background Several effects of leptin in the immune system rely on its capacity to modulate cytokine expression and apoptosis in the thymus. Surprisingly, some of these effects are dependent on signal transduction through the IRS1/PI3-kinase, but not on the activation of JAK2. Since all the well known effects of leptin in different cell types and tissues seem to be dependent on JAK2 activation, we hypothesized that, at least for the control of thymic function, another, unknown kinase could mediate the transduction of the leptin signal from the ObR towards the IRS1/PI3-kinase signaling cascade. Methodology/Principal Findings Here, by employing immunoblot, real-time PCR and flow citometry we show that the tyrosine kinase, Fyn, is constitutively associated with the ObR in thymic cells. Following a leptin stimulus, Fyn undergoes an activating tyrosine phosphorylation and a transient association with IRS1. All these effects are independent of JAK2 activation and, upon Fyn inhibition, the signal transduction towards IRS1/PI3-kinase is abolished. In addition, the inhibition of Fyn significantly modifies the effects of leptin on thymic cytokine expression. Conclusion/Significance Therefore, in the thymus, Fyn acts as a tyrosine kinase that transduces the leptin signal independently of JAK2 activation, and mediates some of the immunomodulatory effects of leptin in this tissue.

Severe hypoleptinaemia associated with insulin resistance in patients with common variable immunodeficiency.

Objective Common variable immunodeficiency (CVI) is a primary immunodeficiency syndrome characterized by impaired production of antibodies and recurrent infections. Delay in diagnosis leads to metabolic wastage and low body weight. Leptin, a hormone produced by white adipose tissue, modulates insulin action by signal transduction cross‐talk and by direct action on pancreatic beta‐cells. We hypothesized that patients with CVI might present a defective regulation of leptin production and insulin resistance.

Type III hypersensitivity to insulin leading to leukocytoclastic vasculitis.

Here, we report the occurrence of leukocytoclastic vasculitis as an outcome of type III allergy to insulin in a patient with type II diabetes mellitus. The diagnosis was made on the basis of anatomo-pathological examination of a skin biopsy.

New mutations in SERPING1 gene of Brazilian patients with hereditary angioedema.

Abstract Hereditary Angioedema is an autosomal dominant inherited disease leading to oedema attacks with variable severity and localization predominantly caused by C1-INH deficit. More than 400 mutations have been already identified, however no genetic analysis of a Brazilian cohort of HAE patients with C1-INH deficiency has been published. Our aim was to perform genetic analysis of C1-INH gene (SERPING1) in Brazilian HAE patients. We screened the whole SERPING1 coding region from 30 subjects out of 16 unrelated families with confirmed diagnosis of HAE due to C1-INH deficiency. Clinical diagnosis was based on symptoms and quantitative and/or functional analysis of C1-INH. We identified fifteen different mutations among which eight were not previously described according to databases. We found five small deletions (c.97_115del19; c.553delG; c.776_782del7; c.1075_1089del15 and c.1353_1354delGA), producing frameshifts leading to premature stop codons; seven missense mutations (c.498C>A; c.550G>C; c.752T>C; c.889G>A; c.1376C>A; c.1396C>T; c.1431C>A); one nonsense mutation (c.1480C>T), and two intronic alterations (c.51+1G>T; c.51+2T>C). Despite the small number of participants in this study, our results show mutations not previously identified in SERPING1 gene. This study represents the first Brazilian HAE cohort evaluated for mutations and it introduces the possibility to perform genetic analysis in case of need for differential diagnosis.

Genetic analysis of hereditary angioedema in a Brazilian family by targeted next generation sequencing.

Abstract Hereditary angioedema (HAE) is accompanied by an overproduction of bradykinin (BK) as the primary mediator of swelling. Although many proteins may be involved in regulating the wide spectrum of HAE symptoms, most studies have only focused on C1-INH and FXII. For the first time, a next generation sequencing (NGS) method was applied to develop a robust, time- and cost-effective diagnostic and research tool to analyze selected genes related to HAE. The entire coding region and the exon-intron boundaries of 15 genes from 23 subjects of a Brazilian family, nine of whom were symptomatic, were analyzed by NGS. One new mutation found uniquely in the nine symptomatic patients, p.Ala457Pro in the SERPING1 gene, was estimated as likely to be pathogenic (PolyPhen-2 software analysis) and is the main candidate to be responsible for HAE in these patients. Alterations identified in a few asymptomatic individuals but also found in almost all symptomatic patients, such as p.Ile197Met (HMWK), p.Glu298Asp (NOS3) and p.Gly354Glu (B2R), may also be involved in modulating patient-specific symptoms. This NGS gene panel has proven to be a valuable tool for a quick and accurate molecular diagnosis of HAE and efficient to indicate modulators of HAE symptoms.

Brazilian Guidelines for Hereditary Angioedema Management - 2017 Update Part 1: Definition, Classification and Diagnosis

Hereditary angioedema is an autosomal dominant disease characterized by recurrent angioedema attacks with the involvement of multiple organs. The disease is unknown to many health professionals and is therefore underdiagnosed. Patients who are not adequately diagnosed and treated have an estimated mortality rate ranging from 25% to 40% due to asphyxiation by laryngeal angioedema. Intestinal angioedema is another important and incapacitating presentation that may be the main or only manifestation during an attack. In this article, a group of experts from the “Associação Brasileira de Alergia e Imunologia (ASBAI)” and the “Grupo de Estudos Brasileiro em Angioedema Hereditário (GEBRAEH)” has updated the Brazilian guidelines for the diagnosis and treatment of hereditary angioedema.

Hereditary Angioedema with Normal C1 Inhibitor and F12 Mutations in 42 Brazilian Families.

BACKGROUND Hereditary angioedema (HAE) with normal C1 inhibitor (C1-INH) is a rare condition with clinical features similar to those of HAE with C1-INH deficiency. Mutations in the F12 gene have been identified in subsets of patients with HAE with normal C1-INH, mostly within families of European descent. OBJECTIVES Our aim was to describe clinical characteristics observed in Brazilians from 42 families with HAE and F12 gene mutations (FXII-HAE), and to compare these findings with those from other populations. METHODS We evaluated a group of 195 individuals, which included 102 patients clinically diagnosed with FXII-HAE and their 93 asymptomatic relatives. RESULTS Genetic analysis revealed that of the 195 subjects, 134 individuals (77.6% females) carried a pathogenic mutation in F12. The T328K substitution was found in 132 individuals, and the c.971_1018+24del72 deletion was found in 2 patients. The mean age at onset of symptoms in patients with FXII-HAE was 21.1 years. The most common symptoms were subcutaneous edema (85.8% of patients), abdominal pain attacks (69.7%), and upper airway edema (32.3%). Of male individuals carrying F12 mutations, 53.3% (16 of 30) were symptomatic. Compared with reports from Europe, fewer female patients (68.6%) reported an influence of estrogen on symptoms. CONCLUSIONS Our study included a large number of patients with FXII-HAE, and, as the first such study conducted in a South American population, it highlighted significant differences between this and other study populations. The high number of symptomatic males and patients with estrogen-independent FXII-HAE found here suggests that male sex and the absence of a hormonal influence should not discourage clinicians from searching for F12 mutations in cases of HAE with normal C1-INH.