CD40LG and dysgammaglobulinemia: Secondary to CD19+ B-cell destruction, patients develop a progressive decrease in all immunoglobulin isotypes (IgG, IgA and IgM): some in a form of dysgammaglobulinemia (deficiency of one or more, but not all, classes of immunoglobulins) and others in the form of agammaglobulinemia (extremely low level of all classes of immunoglobulins).