Combined analysis of double negative T cells and microbiome in pediatric patients with rheumatic and hematological disorders (PED-DNT/MICROBIOME).

Collaborative Research Program 2023-2025

Whereas the specific role of autoantibodies (and B cell in general) and conventional T lymphocytes subset has been deeply investigated in different autoimmune disorders in the last few decades, the implication of “unconventional” T cells (including CD4-CD8- double negative T cells – DNT cells) has not been fully elucidated and methodically investigated, yet. Notably, DNT cells have been also implicated in neoplastic diseases, including lymphoproliferative disorders (such as lymphomas). Indeed, the initial interest for DNT cells arose in the context of Autoimmune Lymphoproliferative Syndrome (ALPS): here lymphoproliferative and autoimmune manifestations are concomitantly present and clinically define this clinical entity; moreover, the increase of peripheral DNT cells represent one of the two required diagnostic criteria.

The first specific objective of this research will be to define the detailed immunophenotype of DNT cells in both pediatric rheumatic children, such as JIA and pSLE patients (with and without lymphoproliferative manifestations), and malignant lymphoproliferative disorders (including lymphomas and also lymphoblastic leukemia), compared to controls represented by both children affected with reactive and transient lymphadenopathies (and/or intercurrent/mild illnesses) and healthy first-degree relatives (and, in detail, siblings). In detail, we aim to identify different subsets of DNTs based on multi-parameter immune-phenotypical characterization by flow cytometry.

Growing evidence suggested that (gut) microbiome is implicated in the ontogenesis of the host’s (adaptive) immune system and, thus, it could also play a role in the immunopathogenesis of several autoimmune disorders. The influence of the microbiome on the immune system may have also some relevance in the tumoral immunosurveillance. So far no research tried to assess the influence of gut microbiome on DNT cells or their potential relationship (if any).

The second specific objective of this research will be to investigate the salivary and fecal microbiome. The microbiome study will be first performed by analyzing 16S rRNA gene sequencing and, following this initial results analysis, will be completed with a shotgun metagenomic approach.

The research objectives will be addressed by an observational, prospective, cross-sectional study, which will include three main groups: i) ““DISEASE” study group, including the rheumatic and oncological disorders which will be the main object of the research, namely Juvenile Idiopathic Arthritis (JIA), pediatric Systemic Lupus Erythematosus (pSLE) and malignant pediatric lymphoproliferative disorders (acute lymphoblastic leukemia - ALL -, and lymphomas, including both Hodgkin lymphoma - HL - and non-Hodgkin lymphomas - NHL -); ii) “FIRST-DEGREE RELATIVES (FDRs) control group, including at least one sibling (preferably, of the same gender) of related patients of the disease group; iii) “UNRELATED” control group, including children affected with transient non-malignant lymphoproliferative diseases (namely, localized/diffuse reactive lymphadenopathy) and children affected by reactive non-lymphoproliferative immune-mediated disorders (e.g. reactive arthritis, post-infectious extra-pulmonary disorders, etc.).