Human Chorionic Gonadotropin Hormone Induces Indoleamine 2,3-Dioxygenase and Interleukin-10 Expression In Patients With Graft-Versus-Host-Disease

Chronic graft-versus-host disease (GVHD) is a major complication following allogeneic hematopoietic stem cell transplantation and is associated with a substantial morbidity and mortality. It is a systemic inflammatory disorder that reflects the lack of immune tolerance between donor-derived immune competent cells and host organs. Human chorionic gonadotropin hormone (hCG) is a natural occurring hormone during pregnancy secreted by syncytiotrophoblasts of the placenta. We had previously observed (Koldehoff et al; J Leukoc Biol 2011) that the rejection of transplanted skin was significantly delayed by hCG in a mouse skin transplant model and had also demonstrated that tryptophan-catabolizing enzyme, indoleamine-2,3-dioxygenase(IDO), interleukin-10 (IL 10) and T-regulatory cells (Tregs) increased significantly in females treated with hCG as preconditioning therapy for in-vitro-fertilization. Since all these factors are known to induce tolerance and given the low rate of adverse effects, we off-label used low dose of hCG to treat 20 patients as forth- or fifth-line therapy with steroid-refractory or intolerant severe-grade chronic GVHD.

Because all of these factors are known to induce tolerance and given the low rate of adverse effects in preconditioning therapy, we off-label used low dose of hCG (187 IU) to treat 8 male and 12 female patients (median age 48, r. 28-68) with moderate or severe grade of chronic GVHD according to the NIH criteria; all patients had been informed of the experimental state of this treatment and provided written consent.

The median number of sites of chronic GVHD involvement per patient was 3 (range, 1-6). hCG therapy was started as 4 or 5th line-therapy together with preexisting medication with prednisone and a calcineurin inhibitor. Twelve of 20 patients (60%) had an objective partial response during 8 weeks of hCG treatment with at least 50% improvement according to the TSS score. Responses included softened skin and subcutaneous tissue; decreased erythema and extent of sclerodermatous, hidebound skin; improved joint mobility and gait; gastrointestinal improvements; and resolution of neuropathy. Nine patients had stable disease (6 with minor responses). Only one patient with previous ATG treatment showed progression of her liver GVHD (histologically proven) and died from GHVD. All other patients were well and alive. Daily low-dose hCG was well tolerated. Adverse events that were possibly related to hCG included reversible and asymptomatic CTCAE grade 4 hypertriglyceridemia (n=1), grade 2 constitutional symptoms (fever, malaise, fatigue; flush, breast enlargement). IDO expression increased up to 8 times and IL10-serum level up to 2 times after 3 weeks of hCG therapy (p<0.003 and p<0.04). T-regulatory cell expansion was documented in 3 patients.

This successful use of hCG in an immune disorder warrants further studies to assess its role as an immunosuppressant in GVHD and potentially other autoimmune disorders.

Off Label Use: The off-label use of HCG will be presented here for the first tiem for treatment of chronic GVHD and will clearly marked as off-label use.