Although the existence of the interaction between sex steroids and immune system is well known, the mechanisms of this interaction are still unclear. Recently a second form of GnRH (GnRH-II) has been described in human, which is significantly expressed in immune tissues suggesting a potential function. In a recent in-vitro study it has been demonstrated that GnRH-II decreases local expression of IL-2R in peripheral lymphocytes (1). However in-vivo interactions of testosterone, IL-2R and GnRH-II expression at lymphocyte level have not been investigated yet. Therefore in the present study we investigated the effects of conventional gonadotrophin therapy on local GnRH-II and IL-2R expression in peripheral lymphocytes in patients with IHH.
Fourteen males with IHH (24.5±6.3) and 15 age-sex matched controls were investigated. Patients were treated with hCG and hMG for 12 months. Quantitative Real-Time RT-PCR (2 independent repeats) was used to determine the expression of GnRH-II (target gene), IL-2R (target gene) and beta-actin (reference gene) in peripheral lymphocytes derived from patients before and after treatment, and the controls.
Serum testosterone level before treatment in patient group was significantly low when compared to controls. After gonadotrophin treatment testosterone level significantly increased. Baseline GnRH-II and IL-2R mRNA levels (% of the control) were % 1451±300 and % 285±46 in the patient group, respectively. Significant decrease in GnRH-II and IL-2R mRNA levels were found after treatment.
In-vivo interactions between testosterone, IL-2R and GnRH-II at lymphocyte level were shown first time in the literature. Present findings clearly suggest that some immune effects of the sex steroids may occur via regulating the local GnRH-II and IL-2R expression.