How do you approach monitoring of specific antibody titers in pediatric patients with 22q11.2 deletion syndrome with normal T cells?

I would start with quantitative immunoglobulin levels (IgG, M, A and E) annually. I'm assuming that the lymphocyte phenotyping has been done and is normal. B cell phenotyping to assess switched memory B cells and transitional B cells could be helpful. It's most important to assess specific antibody ...