CD4 and helminthiasis: These data are consistent with the notion that whilst endogenous populations of nTreg may be sufficient to prevent immune-mediated pathology during chronic infections which induce rather modest inflammatory responses, such as avirulent leishmania, tuberculosis or helminth infections, rapid induction of distinct populations of adaptive/Th1 CD4+ T cells producing IL-10 may be required to counter the powerful inflammatory signals provided by virulent, rapidly replicating pathogens.