Reductions in T-cell thymopoiesis, accumulated highly differentiated memory T cells, loss of CD28 antigen and CD69 antigen for T cell activation and signal transduction, and reduced CD8+ cell proliferation in response to antigen stimulation
Reductions in B-cell lymphopoiesis, increased memory B cells and fewer naive B cells, impaired antibody response to vaccination, and increased production of low-affinity antibodies due to decreased isotype switching