Response to Letter

March 15, 2013

Dear Editor-in-Chief,

I read a letter from Professor Tom Eirik Mollnes, Oslo University. They raised some issues about our results appeared in J Clin Biochem Nutr 2013; 52: 72. We presented the data that the anti-C5-neutralizing antibodies, Eculizumab, prevented the development of dextran-sulfate sodium (DSS)-colitis in mice. We repeatedly confirmed in vivo effects of Eculizumab by the several markers such as body weight loss, the disease activity index, the colonic weight/length ratio, histological colitis score, mucosal myeloperoxidase activity and mucosal cytokine mRNA expression. We have no doubts of in vivo effects of this drug in our model. However, we have no data about inhibition of complement activity in our model.

The issues raised by Prof. Mollnes et al. are based on their in vitro data that Eculizumab is specific for human but does not work in mice. Their data shows Eculizumab does not inhibit mouse complement-mediated lysis in vitro. So, they thought that our in vivo results in mice are independent on inhibition of complement activation.

Since we have no data of complement activities in our model, we cannot make a complete answer. We can simply say that this drug inhibited DSS-colitis in mice. We deeply appreciate the comments by Prof. Mollnes, and our results may include the possible mechanisms independent on complement activation. We will pay attention to the issues raised by Prof. Mollnes in the future experiments in murine models. In addition, further experiments to explore the mechanisms underlying in vivo effects of this drug, including non-complement inhibition, will be performed.

Sincerely yours,

Akira Andoh, MD, PhD