Influence of cutaneous sensitization with oxazolone on recruitment of myelogenous stem cells in the thymus.

Cutaneous sensitization of CBA mice with oxazolone was followed 3 days later by increased cell proliferation in the regional lymph nodes and spleen, as measured by incorporation of radiolabelled 5-iodo-2'-deoxyuridine. The thymus was reduced in weight and contained fewer proliferating cells. Other mice were part-body irradiated, with shielding of the anterior three-quarters of the body, and injected with CBA-T6T6 bone marrow cells. Half of them were subsequently sensitized with oxazolone. The frequency of dividing cells of bone marrow origin in the thymus of sensitized and control animals was estimated cytologically 3–70 days later. There was a significant tendency for sensitized mice to have more dividing cells of donor origin in the thymus than controls.