Altered expression of receptors for thyroid hormone and insulin-like growth factor-1 during reconstitution after allogeneic hematopoietic stem cell transplantation

Treatment with neuroendocrine hormones has been suggested to promote recons titution of the immune system after hematopoietic stem cell transplantation (HSCT). We investigated the expression of genes encoding receptors for gro wth hormone (GH), insulin-like growth factor-1 (IGF-1) and triiodothyronine (T-3), at various time points after HSCT in 16 patients and 15 healthy con trols. Peripheral blood mononuclear cells were isolated and RNA for GH rece ptor (GHR), IGF-I receptor (IGF-IR) and thyroid hormone receptor (TR alpha1 ) was amplified by RT-PCR, The expression of the genes was compared with th e expression of p-actin, We demonstrate increased expression of TR alpha1 R NA in patients at 1.5 months post HSCT, compared to a group of healthy cont rols, and decreased expression of IGF-IR RNA at 2 and 3 months post HSCT, c ompared to the controls. Serum from three of the patients was also analyzed for levels of T-3, T-4, TSH and IGF-1 at several time points after HSCT. S erum levels for T-3, thyroxine (T-4), thyroid stimulating hormone (TSH) and IGF-1 were within the normal range in all samples, Our results on the mole cular level indicate a role for thyroid hormones and IGF-I in immune recons titution after HSCT, even though the serum levels of T-3, T-4, TSH and IGF- I are normal.