A Validated Highly Sensitive Microsatellite Instability Assay Accurately Identifies Individuals Harboring Biallelic Germline PMS2 Pathogenic Variants in Constitutional Mismatch Repair Deficiency.

Background: Constitutional mismatch repair deficiency (CMMRD) is a rare and extraordinarily penetrant childhood-onset cancer predisposition syndrome. Genetic diagnosis is often hampered by the identification of mismatch repair (MMR) variants of unknown significance and difficulties in PMS2 analysis, the most frequently mutated gene in CMMRD. We present the validation of a robust functional tool for CMMRD diagnosis and the characterization of microsatellite instability (MSI) patterns in blood and tumors.

Autoantibodies against type I IFNs in patients with critical influenza pneumonia.

Autoantibodies neutralizing type I interferons (IFNs) can underlie critical COVID-19 pneumonia and yellow fever vaccine disease. We report here on 13 patients harboring autoantibodies neutralizing IFN-α2 alone (five patients) or with IFN-ω (eight patients) from a cohort of 279 patients (4.7%) aged 6-73 yr with critical influenza pneumonia.

Incidence and management of patients with methotrexate delayed elimination in the clinical practice: A Delphi study.

Introduction: High-dose methotrexate (HDMTX) is administered for the treatment of some cancers. HDMTX is usually safe but may crystallize in renal tubules causing acute kidney injury (AKI). Consequently, MTX elimination is delayed, resulting in a severe and life-threatening condition.

Primary Immune Regulatory Disorders With an Autoimmune Lymphoproliferative Syndrome-Like Phenotype: Immunologic Evaluation, Early Diagnosis and Management.

Primary immune regulatory disorders (PIRD) are associated with autoimmunity, autoinflammation and/or dysregulation of lymphocyte homeostasis. Autoimmune lymphoproliferative syndrome (ALPS) is a PIRD due to an apoptotic defect in Fas-FasL pathway and characterized by benign and chronic lymphoproliferation, autoimmunity and increased risk of lymphoma. Clinical manifestations and typical laboratory biomarkers of ALPS have also been found in patients with a gene defect out of the Fas-FasL pathway (ALPS-like disorders).

Two Cases of SARS-CoV-2 Infection in Pediatric Oncohematologic Patients in Spain.

Since December 2019, severe acute respiratory syndrome coronavirus 2 infection has spread worldwide. We all are concerned about immunocompromised children, especially hematologic and oncologic pediatric patients. We want to share our experience with 2 pediatric cancer patients with severe acute respiratory syndrome coronavirus 2 infection.

Flash survey on severe acute respiratory syndrome coronavirus-2 infections in paediatric patients on anticancer treatment.

Introduction: Since the beginning of COVID-19 pandemic, it is known that the severe course of the disease occurs mostly among the elderly, whereas it is rare among children and young adults. Comorbidities, in particular, diabetes and hypertension, clearly associated with age, besides obesity and smoke, are strongly associated with the need for intensive treatment and a dismal outcome. A weaker immunity of the elderly has been proposed as a possible explanation of this uneven age distribution.

[Post chemoterapy febrile neutropenia. Length of stay and experience in our population].

Introduction: Infections are significant cause of morbidity and mortality in cancer patients (mortality is estimated at around 3%). Febrile neutropenia often leads to the hospitalisation of cancer patients, increasing the risk of nosocomial infection, as well as health costs due to the hospital admission.

Methods: An ambispective (01 July 2015 - 12 July 2018) observational study was conducted on all episodes of chemotherapy-induced febrile neutropenia in a paediatric population.

Acquired and Innate Immunity Impairment and Severe Disseminated Infection in a Patient With a NF-κB1 Deficiency.

NF-κB1 is a master regulator of both acquired and innate responses. loss-of-function mutations elicit a wide clinical phenotype with asymptomatic individuals at one end of the spectrum and patients with common variable immunodeficiency, combined immunodeficiency or autoinflammation at the other. Impairment of acquired and innate immunity and disseminated infection expands the clinical and immunological phenotype of NF-κB1 deficiency.

Extreme Phenotypes With Identical Mutations: Two Patients With Same Non-sense Homozygous Mutation.

Cernunnos/XLF deficiency is a rare primary immunodeficiency classified within the DNA repair defects. Patients present with severe growth retardation, microcephaly, lymphopenia and increased cellular sensitivity to ionizing radiation. Here, we describe two unrelated cases with the same non-sense mutation in the gene showing significant differences in clinical presentation and immunological profile but a similar DNA repair defect.

No Overt Clinical Immunodeficiency Despite Immune Biological Abnormalities in Patients With Constitutional Mismatch Repair Deficiency.

Immunoglobulin class-switch recombination (CSR) and somatic hypermutations (SHMs) are prerequisites for antibody and immunoglobulin receptor maturation and adaptive immune diversity. The mismatch repair (MMR) machinery, consisting of homologs of MutSα, MutLα, and MutSβ (MSH2/MSH6, MLH1/PMS2, and MSH2/MSH3, respectively) and other proteins, is involved in CSR, primarily acting as a backup for nonhomologous end-joining repair of activation-induced cytidine deaminase-induced DNA mismatches and, furthermore, in addition to error-prone polymerases, in the repair of SHM-induced DNA breaks. A varying degree of antibody formation defect, from IgA or selective IgG subclass deficiency to common variable immunodeficiency and hyper-IgM syndrome, has been detected in a small number of patients with constitutional mismatch repair deficiency (CMMRD) due to biallelic loss-of-function mutations in one of the MMR genes ().

Intravenous immunoglobulin therapy for refractory recurrent pericarditis.

Recurrent pericarditis is a troublesome complication of idiopathic acute pericarditis and occurs more frequently in pediatric patients after cardiac surgery (postpericardiotomy syndrome). Conventional treatment with nonsteroidal antiinflammatory drugs, corticosteroids, and colchicine is not always effective or may cause serious adverse effects. There is no consensus, however, on how to proceed in those patients whose disease is refractory to conventional therapy.

Presentation of severe combined immunodeficiency with respiratory syncytial virus and pneumocystis co-infection.

Severe combined immunodeficiency can cause severe, life-threatening viral, bacterial and fungal infections at an early age. We report a case of a 4-month-old boy with co-infection by respiratory syncytial virus and Pneumocystis jiroveci infection that led to recognition of severe combined immunodeficiency.

Clinical experience with an L-proline–stabilized 10 %intravenous immunoglobulin (Privigen®): real-life effectiveness and tolerability.

Purpose: This retrospective study evaluated the effectiveness and tolerability in clinical practice of an L-proline-stabilized 10 % intravenous immunoglobulin (IVIG; Privigen®) in patients with primary (PID) or secondary immunodeficiency (SID).

Methods: Patients from 6 centers in Europe and the US were treated with individually determined regimens of Privigen® for ≥3 months. Serum immunoglobulin G (IgG) trough levels, annualized rates of infection, hospitalization and antibiotics use, and the incidence of adverse events (AEs) were analyzed.