Publications by authors named "Julio Orrego"

Introduction: Common variable immunodeficiency is a diagnosis of exclusion in immunodeficient patients with increased susceptibility to infections, hypogammaglobulinemia, deficient response to vaccination, or low percentages of switched memory B cells. In low- and middle-income countries, the elucidation and study of molecular defects in these patients may take decades.

Objective: To elucidate the genetic defect conferring impaired immunity in a patient diagnosed with common variable immunodeficiency.

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Article Synopsis
  • Some babies with a specific mutation in the IL7R gene have a serious immune problem called SCID, where they lack a certain type of immune cells called T cells, but still have normal B and NK cells.
  • In a study of 6 adults who have a similar genetic issue, they showed low levels of T cells but had relatively normal levels of other immune cells, indicating a more specific problem in T cell development.
  • Even though their T cells didn’t grow well in the lab, the study hints that there might be another way T cells can develop that doesn’t depend solely on the IL-7 cytokine.
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Severe defects in human IFNγ immunity predispose individuals to both Bacillus Calmette-Guérin disease and tuberculosis, whereas milder defects predispose only to tuberculosis. Here we report two adults with recurrent pulmonary tuberculosis who are homozygous for a private loss-of-function TNF variant. Neither has any other clinical phenotype and both mount normal clinical and biological inflammatory responses.

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  • CD4+ T cells are crucial for the immune system, but their exact function is not fully understood, particularly the role of the CD4 protein itself.
  • Researchers studied seven patients with a rare genetic condition causing CD4 deficiency, leading to various infections, and found that these individuals lacked CD4+ T cells but had alternative T cell populations that could still mount immune responses.
  • While the patients showed compensatory immune responses against many pathogens, CD4 remains essential for protection against specific infections like human papillomavirus and Whipple's disease.
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Patients with autoimmune polyendocrinopathy syndrome type 1 (APS-1) caused by autosomal recessive AIRE deficiency produce autoantibodies that neutralize type I interferons (IFNs), conferring a predisposition to life-threatening COVID-19 pneumonia. Here we report that patients with autosomal recessive NIK or RELB deficiency, or a specific type of autosomal-dominant NF-κB2 deficiency, also have neutralizing autoantibodies against type I IFNs and are at higher risk of getting life-threatening COVID-19 pneumonia. In patients with autosomal-dominant NF-κB2 deficiency, these autoantibodies are found only in individuals who are heterozygous for variants associated with both transcription (p52 activity) loss of function (LOF) due to impaired p100 processing to generate p52, and regulatory (IκBδ activity) gain of function (GOF) due to the accumulation of unprocessed p100, therefore increasing the inhibitory activity of IκBδ (hereafter, p52/IκBδ).

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Background: Cryptococcosis is a potentially life-threatening fungal disease caused by encapsulated yeasts of the genus Cryptococcus, mostly C. neoformans or C. gattii.

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Objective: Selective IgA deficiency (sIgAD) is the most common primary immunodeficiency in Western countries. Patients can suffer from recurrent infections and autoimmune diseases because of a largely unknown aetiology. To increase insights into the pathophysiology of the disease, we studied memory B and T cells and cytokine concentrations in peripheral blood.

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Purpose: CARD9 deficiency is an inborn error of immunity that predisposes otherwise healthy humans to mucocutaneous and invasive fungal infections, mostly caused by Candida, but also by dermatophytes, Aspergillus, and other fungi. Phaeohyphomycosis are an emerging group of fungal infections caused by dematiaceous fungi (phaeohyphomycetes) and are being increasingly identified in patients with CARD9 deficiency. The Corynespora genus belongs to phaeohyphomycetes and only one adult patient with CARD9 deficiency has been reported to suffer from invasive disease caused by C.

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Purpose: Mendelian susceptibility to mycobacterial disease is a rare clinical condition characterized by a predisposition to infectious diseases caused by poorly virulent mycobacteria. Other infections such as salmonellosis and candidiasis are also reported. The purpose of this article is to describe a young boy affected with various infectious diseases caused by Mycobacterium tuberculosis complex, Salmonella sp, Klebsiella pneumonie, Citrobacter sp.

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Immunoglobulins are heterodimeric proteins composed of 2 heavy chains and 2 light chains. Human immunoglobulin G (IgG) is a plasma derivative and contains more than 95% of IgG. The composition of IgG subclasses is similar to that of normal human plasma.

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Introduction: Chronic granulomatous disease is a primary immunodeficiency that results from mutations in proteins of the NADPH oxidase system that affect the microbicidal activity of phagocytes. Immune reconstitution by hematopoietic stem cell transplantation is currently the only curative therapy for this disease. 

Objective: To describe the clinical and molecular characterization of a patient with X-linked chronic granulomatous disease and the successful immune reconstitution by means of a hematopoietic stem cell transplantation.

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Background: Adverse events following immunization (AEFI) requires special consideration in patients with primary immunodeficiency diseases (PID) because they may represent a "red flag" for the initial diagnosis and may cause disease complications. Therefore, the definition of appropriate vaccination schemes is a major issue in PID. The aim of this study is to describe the AEFI in a cohort of PID patients.

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Purpose: Gain-of-function (GOF) mutations in the signal transducer and activator of transcription 1 (STAT1) result in unbalanced STAT signaling and cause immune dysregulation and immunodeficiency. The latter is often characterized by the susceptibility to recurrent Candida infections, resulting in the clinical picture of chronic mucocutaneous candidiasis (CMC). This study aims to assess the frequency of GOF STAT1 mutations in a large international cohort of CMC patients.

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Introduction: Common variable immunodeficiency is a heterogeneous syndrome characterized by recurrent infections, hypogammaglobulinemia and defective production of specific antibodies. Abnormalities in peripheral blood lymphocyte subpopulations, in particular of B lymphocytes, allow the classification of patients into homogeneous groups.

Objective: To perform a clinical and immunological characterization and to evaluate lymphocyte subpopulations of twelve Colombian patients with common variable immunodeficiency in order to define homogeneous groups.

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Article Synopsis
  • Familial hemophagocytic lymphohistiocytosis (FHL) is a rare disorder that affects the immune system, leading to uncontrolled activation of macrophages and impaired cytotoxic cells.
  • The study describes four patients with FHL type 2 from Latin America, with one diagnosed at 2 months old and the others diagnosed later in childhood, revealing two known genetic mutations (L17fsx50 and R54C).
  • A prevalent genetic haplotype (R54C/A91V) was found in most patients, indicating it may lead to later onset of the disease, underlining the importance of genetic testing for accurate diagnosis of FHL.
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Background: Recurrent infection syndrome (RIS) results from repeated interactions between hosts and environmental infectious agents and is considered normal (NRIS) because of its benign evolution and positive effects in the development of normal immune responses. Abnormal RIS (ARIS) is characterized by the unusually high frequency of severe infections, either as a result of anatomical or functional abnormalities or due to primary or secondary immunodeficiencies (PIDs and SIDs, respectively). Recurrent mucocutaneous infections (MCIs) can be manifestations of RIS or ARIS and could be more frequent in primary immunodeficiencies.

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Recurrent infections are a frequent cause of medical visits. They can be due to a heterogeneous group of dysfunctions that increase the susceptibility to pathogenic and opportunistic microorganisms, such as immunological deficiencies. To define an opportune rational treatment and to guide the molecular diagnosis of primary immunodeficiency diseases, we establish a program for the phenotypic diagnosis of these illnesses in Antioquia, Colombia, including clinical and laboratory evaluations of patients who present recurrent infections with abnormal evolution.

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