Immune function can hardly be studied in a dead body. Well, not yet, anyway. But I have some texts I could lend you, if you're interested, in the systemic effects of various hormones and regulatory cytokines.

I've never personally understood why some people are reluctant to assist with research. Though honestly, you can get lots of subjects if you offer to pay them. Unfortunately, that's considered 'unethical', which sounds like rubbish to me. There's nothing wrong with compensating someone for their time.