CD4 and pneumonitis: Beyond CD4+ T lymphocytes, AIRE-deficient CD8+ T lymphocytes and γδ T lymphocytes have also been implicated in the development of certain -but not all- organ-specific autoimmune manifestations in Aire−/− mice (i.e., oral candidiasis, pneumonitis, retinitis, peripheral neuropathy) and more work is needed to further define their roles in the breakdown of organ-specific tolerance in cooperation with or independent of Aire−/− CD4+ T lymphocytes (6, 59, 60).