Glucocerebroside Alleviates Chronic Graft-Versus-Host-Disease in a Murine Model.

Background: Chronic graft-versus-host-disease (cGVHD) is a major obstacle to successful bone marrow transplantation. NKT lymphocytes may have a role in regulation of the immune attack in cGVHD. Glucocerebroside (GC) is a naturally occurring glycolipid that plays a role in the immune modulation of NKT lymphocytes.

Objectives: To determine the immune modulatory effect of GC in a murine model of cGVHD.

Methods: cGVHD was generated by infusion of 2x10⁷ splenocytes from B10.D2 donor mice into Balb/c recipient mice, which received 7Gy ⁶⁰Co total body irradiation (TBI) prior to transplantation. Recipient mice were followed for 55 days. Histological parameters of cGVHD-associated cutaneous, liver and bowel injury were assessed. To determine the mechanism of GC-mediated immune modulation, intrahepatic and intrasplenic lymphocytes were isolated and analyzed by FACS for CD4+, CD8+,CD56+ and NKT subpopulations. Serum cytokine levels were determined.

Results: Treatment with GC significantly alleviated cGVHD. GC-treated mice gained weight and manifested a significant decrease in skin cGVHD clinical score (0.91 vs. 1.66 in GC treated vs. control mice, respectively). The beneficial effect of GC was associated with a 58% and a 31% reduction of the intrasplenic and the intrahepatic NKT cell number, respectively, accompanied by a 27% decrease of intrasplenic CD3+CD4+ T cells. Intrasplenic (but not intrahepatic) decrease in NK cell number was also observed in GC treated animals (48% vs. 7%). Administration of GC led to increased serum IFNγ and TNFa levels in GC treated compared to untreated controls (46 vs. 27, and 92 vs. 52 pg/ml, respectively), while IL10 levels decreased (61 vs. 83 pg/ml, respectively).

Conclusions: Administration of GC led to significant amelioration of chronic GVHD. This effect was associated with an altered NKT lymphocyte distribution, decreased numbers of effector T lymphocytes and a shift towards a Th1-type cytokine profile. Glucocerebroside may serve as a new therapeutic measure for amelioration of cGVHD.