Endocrine involvement in minor (non-H-2) graft-versus-host reaction in mice. Early and primary thyroid failure

A minor (non-H-2) graft-vs.-host reaction (GVHR) was induced in adult irradiated (DBA/2 X B10.D2)F1 mice by hematopoietic parental B10.D2 cell grafts. Syngeneic (F1) cell transplantation was performed as control. In one set of experiments T4 plasma level (enzyme linked immunosorbent assay) was systematically followed up in individual GVHR and control mice. Compared to the control, GVHR triggered off a significant and sustained decrease of T4 plasma level. In another set of experiments, TSH plasma levels (RIA) were measured in killed animals. GVHR induced an early elevation of plasma TSH. In a third set of experiments, mice undergoing GVHR received daily injections of L-T4 (0.03, 0.15, or 0.3 microgram/mouse). Compared to the control (saline injected) GVHR mice, T4 supply did not improve GVHR state. No positive effect of the high dose and rather a negative effect of both lower doses especially on glucose plasma concentration, were observed. All these data suggest that thyroid gland is primarily and very early involved in the onset of the GVH disease.