22q11.2 deletion 22q11.2 deletion syndrome B cell maturation CD4+ cells COVID-19 CTLA-4 CVID DNA methylation DiGeorge syndrome Foxp3 Giardia IKAROS IKZF1 IPEX Immune dysregulation Immunoglobulin E Immunoglobulin deficiency LRBA PIMS-TS R162Q SARS-CoV-2 T cell maturation T-cell response TNFRSF13B mutations X-linked agammaglobulinemia activated phosphoinositide 3-kinase d syndrome allergy anti-SARS-CoV-2 antibodies array-CGH atopic diseases