Anti-GM-CSF Neutralizing Autoantibodies in Colombian Patients with Disseminated Cryptococcosis.

BACKGROUND: Cryptococcosis is a potentially life-threatening fungal disease caused by encapsulated yeasts of the genus Cryptococcus, mostly C. neoformans or C. gattii. Cryptococcal meningitis is the most frequent clinical manifestation in humans. Neutralizing autoantibodies (auto-Abs) against granulocyte-macrophage colony-stimulating factor (GM-CSF) have recently been discovered in otherwise healthy adult patients with cryptococcal meningitis, mostly caused by C. gattii. We hypothesized that three Colombian patients with cryptococcal meningitis caused by C. neoformans in two of them would carry high plasma levels of neutralizing auto-Abs against GM-CSF. METHODS: We reviewed medical and laboratory records, performed immunological evaluations, and tested for anti-cytokine auto-Abs three previously healthy HIV-negative adults with disseminated cryptococcosis. RESULTS: Peripheral blood leukocyte subset levels and serum immunoglobulin concentrations were within the normal ranges. We detected high levels of neutralizing auto-Abs against GM-CSF in the plasma of all three patients. CONCLUSIONS: We report three Colombian patients with disseminated cryptococcosis associated with neutralizing auto-Abs against GM-CSF. Further studies should evaluate the genetic contribution to anti-GM-CSF autoantibody production and the role of the GM-CSF signaling pathway in the immune response to Cryptococcus spp.

Mendelian Susceptibility to Mycobacterial Disease: Retrospective Clinical and Genetic Study in Mexico.

Mendelian susceptibility to mycobacterial disease (MSMD) is a rare genetic disorder characterized by impaired immunity against intracellular pathogens, such as mycobacteria, attenuated Mycobacterium bovis-Bacillus Calmette-Guérin (BCG) vaccine strains, and environmental mycobacteria in otherwise healthy individuals. Retrospective study reviewed the clinical, immunological, and genetic characteristics of patients with MSMD in Mexico. Overall, 22 patients diagnosed with MSMD from 2006 to 2021 were enrolled: 14 males (64%) and eight females. After BCG vaccination, 12 patients (70%) developed BCG infection. Furthermore, 6 (22%) patients developed bacterial infections mainly caused by Salmonella, as what is described next in the text is fungal infections, particularly Histoplasma. Seven patients died of disseminated BCG disease. Thirteen different pathogenic variants were identified in IL12RB1 (n = 13), IFNGR1 (n = 3), and IFNGR2 (n = 1) genes. Interleukin-12Rß1 deficiency is the leading cause of MSMD in our cohort. Morbidity and mortality were primarily due to BCG infection.

Genetic, Immunological, and Clinical Features of the First Mexican Cohort of Patients with Chronic Granulomatous Disease.

PURPOSE: Chronic granulomatous disease (CGD) is a primary immunodeficiency characterized by an inability of phagocytes to produce reactive oxygen species, impairing their killing of various bacteria and fungi. We summarize here the 93 cases of CGD diagnosed in Mexico from 2011 to 2019. METHODS: Thirteen Mexican hospitals participated in this study. We describe the genetic, immunological, and clinical features of the 93 CGD patients from 78 unrelated kindreds. RESULTS: Eighty-two of the patients (88%) were male. All patients developed bacterial infections and 30% suffered from some kind of fungal infection. Fifty-four BCG-vaccinated patients (58%) presented infectious complications of BCG vaccine. Tuberculosis occurred in 29%. Granulomas were found in 56% of the patients. Autoimmune and inflammatory diseases were present in 15% of patients. A biological diagnosis of CGD was made in 89/93 patients, on the basis of NBT assay (n = 6), DHR (n = 27), and NBT plus DHR (n = 56). The deficiency was complete in all patients. The median age of biological diagnosis was 17 months (range, 0-186 months). A genetic diagnosis was made in 83/93 patients (when material was available), corresponding to CYBB (n = 64), NCF1 (n = 7), NCF2 (n = 7), and CYBA (n = 5) mutations. CONCLUSIONS: The clinical manifestations in these Mexican CGD patients were similar to those in patients elsewhere. This cohort is the largest in Latin America. Mycobacterial infections are an important cause of morbidity in Mexico, as in other countries in which tuberculosis is endemic and infants are vaccinated with BCG. X-linked CGD accounted for most of the cases in Mexico, as in other Latin American countries. However, a significant number of CYBA and NCF2 mutations were identified, expanding the spectrum of known causal mutations.

Paracoccidioidomycosis Associated With a Heterozygous STAT4 Mutation and Impaired IFN-γ Immunity.

Background: Mutations in genes affecting interferon-γ (IFN-γ) immunity have contributed to understand the role of IFN-γ in protection against intracellular pathogens. However, inborn errors in STAT4, which controls interleukin-12 (IL-12) responses, have not yet been reported. Our objective was to determine the genetic defect in a family with a history of paracoccidioidomycosis. Methods: Genetic analysis was performed by whole-exome sequencing and Sanger sequencing. STAT4 phosphorylation (pSTAT4) and translocation to the nucleus, IFN-γ release by patient lymphocytes, and microbicidal activity of patient monocytes/macrophages were assessed. The effect on STAT4 function was evaluated by site-directed mutagenesis using a lymphoblastoid B cell line (B-LCL) and U3A cells. Results: A heterozygous missense mutation, c.1952 A>T (p.E651V) in STAT4 was identified in the index patient and her father. Patient's and father's lymphocytes showed reduced pSTAT4, nuclear translocation, and impaired IFN-γ production. Mutant B-LCL and U3A cells also displayed reduced pSTAT4. Patient's and father's peripheral blood mononuclear cells and macrophages demonstrated impaired fungicidal activity compared with those from healthy controls that improved in the presence of recombinant human IFN-γ, but not rhIL-12. Conclusion: Our data suggest autosomal dominant STAT4 deficiency as a novel inborn error of IL-12-dependent IFN-γ immunity associated with susceptibility to paracoccidioidomycosis.

Microbial Disease Spectrum Linked to a Novel IL-12Rß1 N-Terminal Signal Peptide Stop-Gain Homozygous Mutation with Paradoxical Receptor Cell-Surface Expression.

Patients with Mendelian Susceptibility to Mycobacterial Diseases (MSMD) exhibit variable vulnerability to infections by mycobacteria and other intramacrophagic bacteria (e.g., Salmonella and Klebsiella) and fungi (e.g., Histoplasma, Candida, Paracoccidioides, Coccidioides, and Cryptococcus). The hallmark of MSMD is the inherited impaired production of interferon gamma (IFN-γ) or the lack of response to it. Mutations in the interleukin (IL)-12 receptor subunit beta 1 (IL12RB1) gene accounts for 38% of cases of MSMD. Most IL12RB1 pathogenic allele mutations, including ten known stop-gain variants, cause IL-12Rß1 complete deficiency (immunodeficiency-30, IMD30) by knocking out receptor cell-surface expression. IL12RB1 loss-of-function genotypes impair both IL-12 and IL-23 responses. Here, we assess the health effects of a rare, novel IL12RB1 stop-gain homozygous genotype with paradoxical IL-12Rß1 cell-surface expression. We appraise four MSMD children from three unrelated Brazilian kindreds by clinical consultation, medical records, and genetic and immunologic studies. The clinical spectrum narrowed down to Bacillus Calmette-Guerin (BCG) vaccine-related suppurative adenitis in all patients with one death, and recrudescence in two, histoplasmosis, and recurrence in one patient, extraintestinal salmonellosis in one child, and cutaneous vasculitis in another. In three patients, we established the homozygous Trp7Ter predicted loss-of-function inherited genotype and inferred it from the heterozygote parents of the fourth case. The Trp7Ter mutation maps to the predicted IL-12Rß1 N-terminal signal peptide sequence. BCG- or phytohemagglutinin-blasts from the three patients have reduced cell-surface expression of IL-12Rß1 with impaired production of IFN-γ and IL-17A. Screening of 227 unrelated healthy subjects from the same geographic region revealed one heterozygous genotype (allele frequency 0.0022) vs. one in over 841,883 public genome/exomes. We also show that the carriers bear European ancestry-informative alleles and share the extended CACCAGTCCGG IL12RB1 haplotype that occurs worldwide with a frequency of 8.4%. We conclude that the novel IL12RB1 N-terminal signal peptide stop-gain loss-of-function homozygous genotype confers IL-12Rß1 deficiency with varying severity and early-onset age through diminished cell-surface expression of an impaired IL-12Rß1 polypeptide. We firmly recommend attending to warning signs of IMD30 in children who are HIV-1 negative with a history of adverse effects to the BCG vaccine and presenting with recurrent Histoplasma spp. and extraintestinal Salmonella spp. infections.

A patient with tyrosine kinase 2 deficiency without hyper-IgE syndrome.

We describe a Turkish patient with tyrosine kinase 2 deficiency who suffered from disseminated Bacille Calmette-Guerin infection, neurobrucellosis, and cutaneous herpes zoster infection. Tyrosine kinase 2 deficiency should be considered in patients susceptible to herpes viruses and intramacrophage pathogens even in the absence of atopy, high serum IgE, and staphylococcal disease.

Clinical disease caused by Klebsiella in 2 unrelated patients with interleukin 12 receptor beta1 deficiency.

Patients with interleukin 12 (IL-12)p40 or IL-12 receptor ß1 (IL12Rß1) deficiencies are prone to develop infections caused by mycobacteria and salmonella; other infections have only been rarely observed. In this report we describe 2 unrelated patients with complete autosomal recessive IL12Rß1 deficiency who suffered from sepsis attributable to Klebsiella pneumoniae. A Mexican boy suffered from disseminated bacille Calmette-Guérin disease and infections caused by K pneumoniae and Candida albicans and had a fatal outcome. A Turkish girl living in France suffered from disseminated Nocardia nova infection and K pneumoniae sepsis. Therefore, Klebsiella infections should be considered in patients with IL12Rß1 deficiency. Conversely, IL12Rß1 deficiency should be considered in patients with unexplained klebsiellosis.

HHV-8-associated Kaposi sarcoma in a child with IFNgammaR1 deficiency.

OBJECTIVES: Mediterranean classic Kaposi sarcoma (KS) of childhood is rare and unexplained. Our objective is to describe the case of a child with complete IFNgammaR1 deficiency and severe mycobacterial disease in whom Kaposi sarcoma (KS) developed. RESULTS: Disseminated mycobacterial infection began at the age of 5 months, and at 11 years of age the child had disseminated KS lesions. The histologic appearance of these lesions was typical, with endothelial and spindle cell proliferation. Human herpesvirus-8 (HHV-8)-associated antigens were detected in situ by immunohistochemistry. HHV-8 DNA of K1 molecular subtype A was amplified from tissue lesions, and HHV-8-specific antibodies were detected in the patient's serum. The child died at 12 years of age of disseminated mycobacterial disease and KS. CONCLUSIONS: This is the first identification of a well-defined primary immunodeficiency in a child with KS. Inherited disorders of IFN-gamma-mediated immunity and severe mycobacterial disease may predispose HHV-8-infected children to KS.