EXPANDED NEWBORN SCREENING FOR INBORN ERRORS OF IMMUNITY: THE EXPERIENCE OF TUSCANY

BACKGROUND

Inborn errors of immunity (IEIs) include 485 inherited disorders characterized by an increased susceptibility to life threatening infectious diseases, autoimmunity and malignant diseases with a high mortality rate in the first years of life. Severe Combined Immunodeficiency is the most severe of the IEIs and its detection should be a primary goal in a newborn screening (NBS) program. The term "actionable" has recently been used for all IEIs with outcomes that can be demonstrably improved through early specialized intervention.

OBJECTIVE

to evaluate the results of the expanded NBS strategy for IEIs in Tuscany Region (Italy), based on TREC (T-cell Receptor Excision Circles), KREC (Kappa Recombining Excision Circles) and Tandem Mass-based assays.

METHODS

This is a retrospective study collecting data from all infants born in Tuscany from October 10, 2018, to October 10, 2022. Tandem mass assay to identify Adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) deficiency, together with TREC and KREC molecular analysis were conducted on dried blood spot (DBS) from the newborns' Guthrie Cards. A new DBS and evaluation by an immunologist were carried out when the results of the first test were outside the diagnostic cut-offs.

RESULTS

94,319 newborns were evaluated. Referral rates for TREC (0.031%) and KREC (0.074%) in this study are in line with the data available in literature. The results from the expanded NBS strategy revealed an incidence rate of 1/9,431 affected newborns.

CONCLUSION

This work represents the first description of a sustainable and real-life based expanded NBS program for IEIs with a high diagnostic incidence facilitating prompt management of identified patients.

Analysis of a Cohort of 165 Pediatric Patients with Human Bocavirus Infection and Comparison between Mono-Infection and Respiratory Co-Infections: A Retrospective Study

INTRODUCTION

Human Bocavirus (HBoV) is mainly associated with respiratory tract infections. However, its role as respiratory pathogen is not fully understood for a high co-infection rate in symptomatic patients and a significant HBoV detection rate in asymptomatic subjects. This study aimed to describe a large cohort of children with HBoV infection and to compare HBoV mono-infection and co-infections.

METHODS

We retrospectively reviewed data from 165 children admitted to Meyer Children's Hospital IRCCS from March 2022 to March 2023 with the diagnosis of HBoV infection, detected using Reverse Transcription qPCR from nasal swabs. Thereafter, we compared patients with HBoV mono-infection (Group A) and those with HBoV co-infections (Group B) in terms of disease severity, established by the length of stay (LOS), the requirement of Pediatric Intensive Care Unit (PICU), and advanced respiratory support (ARS).

RESULTS

The median age was 1.5 years; 80% of patients presented with respiratory symptoms. The discharge rate from the emergency department (ED) within 24 h was 42.4%. Most cases (57.6%) were hospitalized, and 7.3% were admitted to PICU due to respiratory failure. Group A comprised 69 patients, and Group B 96 children (95% viral co-infections, 2% bacterial, 3% viral and bacterial). Group A and Group B were similar in hospitalization rate but differed significantly in LOS (median 3 vs. 5 days) and requirement of PICU admission (0 vs. 12 patients, p < 0.001). Patients with a respiratory disease history (17.5%) showed significantly longer LOS and more necessity of inhaled bronchodilator therapy.

CONCLUSIONS

HBoV should be considered a relevant respiratory pathogen especially in viral co-infections. Patients with HBoV co-infections have a higher risk of necessitating advanced respiratory support with more PICU admission and longer LOS; a previous respiratory disease puts them at a higher risk of longer hospitalization.

Food Protein-induced Enterocolitis Syndrome Due to Cuttlefish in a Child with Anaphylaxis to Crustaceans

Shellfish is defined as any edible marine invertebrate and refers to crustaceans and mollusks. Crustaceans belong to the phylum Arthropods. Mollusks belong to the phylum Mollusca. This report illustrates a rare case of a 6-year-old girl with challenge-proven acute food protein-induced enterocolitis syndrome (FPIES) to cuttlefish (phylum Mollusca, class Cephalopoda), anaphylaxis to crustaceans (phylum Arthropoda), and tolerance to other mollusks, including clams and mussels (phylum Mollusca, class Bivalvia). The association of IgE-mediated food allergy and acute FPIES seen in this case is rare. To our knowledge, this is the first case of FPIES to cuttlefish reported in a child. This challenge highlights the need for further research into the allergens and mechanisms underpinning FPIES at a molecular level, enabling a better understanding of cross-reactivity patterns and the development of diagnostic and predictive tests to assist in clinical practice.

CD38high/HLA-DR+ CD8+ T cells as potential biomarker of hemophagocytic lymphohistiocytosis secondary to visceral Leishmania infection

Leishmaniasis is a cause of infection associated with hemophagocytic lymphohistiocytosis (HLH). The measurement of the CD8⁺ CD38^high/HLA-DR⁺ T cells in children presenting with acute onset of shock and multisystem organ failure represents an important parameter to distinguish HLH from sepsis or healthy control.

CONCLUSION

We report a case series of 4 Italian children suffering from HLH secondary to visceral Leishmaniasis in which the lymphocyte subset assay suggests a potential role of CD38^high/HLA-DR⁺ CD8⁺ T cells as HLH diagnostic biomarkers.

WHAT IS KNOWN

• Visceral Leishmaniasis is a well-known cause of infection associated with hemophagocytic lymphohistiocytosis (HLH). • The measurement of the CD8⁺ CD38^high/HLA-DR⁺ T cells in children presenting with acute onset of shock and multisystem organ failure represents an important diagnostically useful parameter to readily distinguish HLH from sepsis or healthy controls.

WHAT IS NEW

• We report a case series of 4 Italian children suffering from HLH secondary to visceral Leishmaniasis in which the lymphocyte subset assay suggests a potential role of CD38^high/HLA-DR⁺ CD8⁺ T cells as HLH diagnostic biomarker. • The flow cytometry assay, performed at the disease onset before starting treatment, revealed a mean percentage value of CD38 cells of 36.95% among CD8⁺ T cells.