Lung infections in immunocompromised children.

Pulmonary infection is the leading cause of infectious morbidity and mortality in children with immune defects. We provide a comprehensive review of lung infections in immunocompromised children, with a focus on imaging findings and imaging-based management. We include an overview of the immune defences of the respiratory tract, the aetiologies of immune defects in children, the features of specific infections and important differential diagnoses and describe diagnostic strategies using imaging and non-imaging-based techniques.

Non-osteopenic Bone Pathology After Allo-hematopoietic Stem Cell Transplantation in Patients with Inborn Errors of Immunity.

Purpose: There is a lack of data on post-HSCT non-osteopenic bone pathology specifically for children with inborn errors of immunity (IEI). We collected data on non-osteopenic bone pathology in children with IEI post-HSCT over two decades in a large tertiary pediatric immunology center.

Methods: Descriptive study with data analysis of bone pathology in allo-HSCT for IEI was performed between 1/1/2000 to 31/12/2018 including patients alive at follow-up to July 2022.

Influenza A/H1N1 vaccination response is inadequate in down syndrome children when the latest cut-off values are used.

We determined the response of 48 Down syndrome children to 2 doses of influenza A/H1N1 vaccination. Ninety-two percent of the children reached the previously defined protective level (hemagglutination-inhibition titer ≥1:40), but only 27% of the children reached the level of ≥1:110 which was recently described to predict the conventional 50% clinical protection rate in children. Further studies, and potentially adaptations of the schedule, are needed.

Down syndrome: is it really characterized by precocious immunosenescence?

The immune system declines with aging, leading to an increased susceptibility to infections and higher incidence and progression of autoimmune phenomena and neoplasia. Down syndrome prematurely shows clinical manifestations that are normally seen with aging. This review provides a concise overview of abnormalities in the adaptive immune system of Down syndrome in comparison to normal and precocious (Progeria syndromes) aging.

Impaired avidity maturation after tetanus toxoid booster in children with Down syndrome.

Down syndrome children show a decreased avidity of the antibody response after tetanus toxoid booster vaccination at 9 years of age suggesting impaired memory B cell selection in the germinal center. Clinicians need to be aware of this ongoing subtle immunologic deficit in Down syndrome.

Both normal memory counts and decreased naive cells favor intrinsic defect over early senescence of Down syndrome T lymphocytes.

Because of their increased malignancies, autoimmune diseases, and infections, patients with Down syndrome (DS) show features of immunodeficiency. The DS thymus and T lymphocyte subsets have indeed proven to be different, and this has been interpreted as precocious aging. Our study on T lymphocyte subpopulations in DS shows that the normal expansion of naive helper (CD4CD45RA) and cytotoxic (CD8CD45RACD27) T lymphocytes is lacking in the first years of life; this is more logically explainable with an intrinsic T lymphocyte defect.

Down syndrome B-lymphocyte subpopulations, intrinsic defect or decreased T-lymphocyte help.

Down syndrome (DS) is known for increased incidence of respiratory infections and autoimmune diseases, indicating impaired immunity. Until now, attention has been mainly focused on T lymphocytes. Therefore, we determined B-lymphocyte subpopulations in 95 children with DS compared with 33 age-matched control (AMC) children.