Around this time, he was reviewed in the Allergy and Immunology clinic at the same time as his sister and also had mild IgA deficiency of 0.18 g/L (reference range: 0.22–2.20 g/L) identified in the context of a borderline low IgM level 0.37 g/L (reference range: 0.40–1.40 g/L) but normal IgG, serum albumin and otherwise normal immune function testing (full blood count, lymphocyte subsets, naïve T cells, immunoglobulins, regulatory T cells, tetanus antibodies, interferon antibody testing). Here, ALB is linked to tetanus.