Intermittent neutropenia (810/ μL; RV: 1500-8500****). Normal lymphocyte counts. Expansion of B transitional cells (47.74%; RV: 0.7-24*).Absent IgA with normal IgG and IgM. Elevated IgE (96 kU/L).Reduced proliferation assays.Decreased specific anti-polisacaridic antibodies after vaccination.Recurrent respiratory infections, sepsis adenopathies, diarrheas, oral ulcers, atopic dermatitis, failure to thrive. The gene discussed is CD40LG; the disease is Sepsis.