Further, improvements in hygiene, associated with fewer infections with parasites and other pathogens, have been associated with a greater prevalence of autoimmune diseases . The increased stimulation of cross-reactive Tregs due to past or present helminth infections could explain the spontaneous production of IL-10 observed in the present study. Because
these cells may have been stimulated in vivo, they may suffer apoptosis when stimulated by A. lumbricoides antigens
in vitro. This might explain our observation for the failure of A. lumbricoides antigen to induce IL-10 production by PBLs from helminth-infected children in vitro. This hypothesis has been reviewed in detail elsewhere