Influence of combined treatment of low dose rapamycin and cyclosporin A on corneal allograft survival

• Published in: Graefe's archive for clinical and experimental ophthalmology 2010-10, Vol.248 (10), p.1447-1456
• Main Authors: Stanojlovic, Svetlana, Schlickeiser, Stephan, Appelt, Christine, Vogt, Katrin, Schmitt-Knosalla, Isabela, Haase, Stefanie, Ritter, Thomas, Sawitzki, Birgit, Pleyer, Uwe
• Format: Article
• Language: English
• Subjects: Animals; Cornea; Cornea - drug effects; Cornea - immunology; Cornea - pathology; Cyclosporine - administration & dosage; Cytokines - genetics; Disease Models, Animal; Drug Therapy, Combination; Flow Cytometry; Graft Survival - drug effects; Graft Survival - immunology; Immunosuppressive Agents - administration & dosage; Injections, Intraperitoneal; Keratoplasty, Penetrating; Lymphoid Tissue - immunology; Male; Medicine; Medicine & Public Health; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Ophthalmology; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - metabolism; Sirolimus - administration & dosage; T-Lymphocytes, Regulatory - immunology; Transplantation, Homologous
• ISSN: 0721-832X; 1435-702X
• DOI: 10.1007/s00417-010-1420-z

Purpose To analyze the immune modulatory effect of low-dose systemic treatment with rapamycin (Rapa) alone or in combination with cyclosporin A (CsA) in a high-responder corneal allograft model. Methods A total of 80 C57BL/6 mice received corneal grafts from BALB/c donors. Recipients were treated with either CsA 3 mg/kg/day or Rapa 0.5 mg/kg/day monotherapy or received combined treatment. Immunomodulatory treatment was started on the day of surgery, and continued for 14 days. The frequency of CD4 + CD25 + Foxp3 + T regulatory cells (Treg) in secondary lymphoid organs was measured by flow cytometry. Development of IFN-γ producing alloreactive T cells was estimated by Elispot. In addition, corneal samples were subjected to real-time RT-PCR analysis for cytokine transcription. Results Monotherapy with Rapa significantly delayed allograft rejection (13.4 ± 1.34 days, p  = 0.03). However, the combination of both, low-dose Rapa and CsA prolonged corneal allograft survival at a significantly higher level (MST = 17.1 ± 1.37 days, p  = 0.0001) than in the control group (MST = 11.2 ± 1.91 days). Rapa monotherapy increased the frequency of CD4 + CD25 + Foxp3 + Treg in draining lymph nodes, whereas addition of CsA reduced Tregs. Monotherapy with Rapa as well as combined treatment prevented development of IFN-γ producing alloreactive T cells in spleen. Combined treatment resulted in down-regulation of intragraft CD3, IL-2, IFN-γ and IL-10 transcription ( p  = 0.028, p  = 0.027, p  = 0.028 and p  = 0.027 respectively). Conclusions Combined treatment with low-dose CsA and Rapa resulted in superior graft survival, and effectively modulated mRNA expression of inflammation and infiltration markers.