Using the colitis transfer model, we showed that IL - 10 produced by a
subset of
myeloid cells in the Rag - / - recipients is required for colitis suppression by transferred Treg.
It was heterozygous in most patients, homozygous in a
subset as a result of mitotic recombination, and arose in a multipotent progenitor capable of giving rise to erythroid and
myeloid cells.