Thrombocytopenia (64000/μL; RV: 150000-370000***). Normal lymphocyte counts and TBNK subpopulations.Low IgG (382 mg/dl; RV: 639-1349**), IgA (29 mg/dl; RV: 70-312**) and IgM (20 mg/dl; RV: 56-352). Normal proliferation assays.Atopic dermatitis, adenopathies, recurrent respiratory infections, diarrhoeas. The gene discussed is CD40LG; the disease is respiratory tract infectious disorder.