Open Access Research

Inhibition of allogeneic inflammatory responses by the Ribonucleotide Reductase Inhibitors, Didox and Trimidox

Mohammed S Inayat1, Ismail S El-Amouri1, Mohammad Bani-Ahmad1, Howard L Elford2, Vincent S Gallicchio3 and Oliver R Oakley1*

Author Affiliations

1 Department of Clinical Sciences, University of Kentucky, Lexington, KY 40536, USA

2 Molecules for Health, Inc., Richmond, VA 23219, USA

3 Departments of Biological Sciences and Public Health Sciences, Clemson University, Clemson, SC 29634, USA

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Journal of Inflammation 2010, 7:43  doi:10.1186/1476-9255-7-43

Published: 18 August 2010



Graft-versus-host disease is the single most important obstacle facing successful allogeneic stem cell transplantation (SCT). Even with current immunosuppressive therapies, morbidity and mortality rates are high. Current therapies including cyclosporine A (CyA) and related compounds target IL-2 signaling. However, although these compounds offer great benefit, they are also associated with multiple toxicities. Therefore, new compounds with a greater efficacy and reduced toxicity are needed to enable us to overcome this hurdle.


The allogeneic mixed lymphocyte reaction (MLR) is a unique ex vivo method to study a drug's action on the initial events resulting in T-cell activation and proliferation, synonymous to the initial stages of tissue and organ destruction by T-cell responses in organ rejection and Graft-versus-host disease. Using this approach, we examined the effectiveness of two ribonucleotide reductase inhibitors (RRI), Didox and Trimidox, to inhibit T-cell activation and proliferation.


The compounds caused a marked reduction in the proliferative responses of T-cells, which is also accompanied by decreased secretion of cytokines IL-6, IFN-γ, TNF-α, IL-2, IL-13, IL-10 and IL-4.


In conclusion, these data provide critical information to justify further investigation into the potential use of these compounds post allogeneic bone marrow transplantation to alleviate graft-versus-host disease thereby achieving better outcomes.