A reversion of an IL2RG mutation in combined immunodeficiency providing competitive advantage to the majority of CD8+ T cells

Mutations in the common gamma chain (γc, CD132, encoded by the IL2RG gene) can lead to B+T-NK-X-linked severe combined immunodeficiency, as a consequence of unresponsiveness to γc-cytokines such as interleukins-2, -7 and -15. Hypomorphic mutations in CD132 may cause combined immunodeficiencies with a variety of clinical presentations. We analyzed peripheral blood mononuclear cells of a 6-year-old boy with normal lymphocyte counts, who suffered from recurrent pneumonia and disseminated mollusca contagiosa. Since proliferative responses of T cells and NK cells to γc -cytokines were severely impaired, we performed IL2RG gene analysis, showing a heterozygous mutation in the presence of a single X-chromosome. Interestingly, an IL2RG reversion to normal predominated in both naïve and antigen-primed CD8+ T cells and increased over time. Only the revertant CD8+T cells showed normal expression of CD132 and the various CD8+T cell populations had a different T-cell receptor repertoire. Finally, a fraction of γδ+T cells and differentiated CD4+CD27-effector-memory T cells carried the reversion, whereas NK or B cells were repeatedly negative. In conclusion, in a patient with a novel IL2RG mutation, gene-reverted CD8+T cells accumulated over time. Our data indicate that selective outgrowth of particular T-cell subsets may occur following reversion at the level of committed T progenitor cells

A software tool for estimation of burden of infectious diseases in Europe using incidence-based disability adjusted life years

The burden of disease framework facilitates the assessment of the health impact of diseases through the use of summary measures of population health such as Disability- Adjusted Life Years (DALYs). However, calculating, interpreting and communicating the results of studies using this methodology poses a challenge. The aim of the Burden of Commu

Impact of infectious diseases on population health using incidence-based disability-adjusted life years (DALYs)

Background and aims: The Burden of Communicable Diseases in Europe (BCoDE) study aimed to calculate disability-adjusted life years (DALYs) for 31 selected diseases in the European Union (EU) and European Economic Area (EEA). Methods: DALYs were estimated using an incidence-based and pathogen-based approach. Incidence was estimated through assessment of data availability and quality, and a correction was applied for under-estimation. Calculation of DALYs was performed with the BCoDE software toolkit without applying time discounting and age-weighting. Results: W

Idiopathic CD4+ T lymphopenia without autoimmunity or granulomatous disease in the slipstream of RAG mutations

A girl presented during childhood with a single course of extensive chickenpox and moderate albeit recurrent pneumonia in the presence of idiopathic CD4+T lymphocytopenia (ICL). Her clinical condition remained stable over the past 10 years without infections, any granulomatous disease, or autoimmunity. Immunophenotyping demonstrated strongly reduced naive T and B cells with intact proliferative capacity. Antibody reactivity on in vivo immunizations was normal. T-cell receptor-Vβ repertoire was polyclonal with a very low content of T-cell receptor excision circles (TRECs). Kappa-deleting recombination excision circles (KRECs) were also abnormal in the B cells. Both reflect extensive in vivo proliferation. Patient-derived CD34+hematopoietic stem cells could not repopulate RAG2-/-IL2Rγc-/-mice, indicating the lymphoid origin of the defect. We identi-fied 2 novel missense mutations in RAG1 (p.Arg474Cys and p.Leu506Phe) resulting in reduced RAG activity. This report gives the first genetic clue for ICL and extends the clinical spectrum of RAG mutations from severe immune defects to an almost normal condition