Lymphoid cell proliferation in non-lymphoid organs during graft-versus-host reactions (GVHR): I. Lack of correlation between mortality and grafted cell proliferation.

The course of development of graft-versus-host reactions (GVHR) following lethal irradiation was compared in two mouse donor-host combinations disparate at non H-2 loci alone or associated to H-2 complex. The pathogenesis of these reactions was very different (mortality rates faster in the second situation for example). The donor cell proliferation kinetics was followed in lymphoid (pooled lymph nodes, spleen, thymus) and in non-lymphoid organs (kidney and liver) from day 0 to day 28 post-transplantation, and showed the same profile in both GVH reactions. Our data emphasize the discordance between the clinical evolution of the GVH disease on one hand, and the stimulation of the grafted cell proliferation on the other hand, induced by a same H-2 disparity. In addition, we have demonstrated the relatively high level of the lymphocyte proliferation in non-lymphoid organs during the course of a GVHR, even in the case of minor histoincompatibility.