Human genome determines who we are in terms of species difference, although other vertibrate species such as mice, contain up to 99% of gene counterparts. One can argue that only 1% is needed to make such big difference. I don’t want to disagree.
What I really want to say is that our genome may also determine how our immune system works. It should not sound inconsistent with what I just said above. It’s been proven that our immunity can be compromised due to certain mutations that may be inheritable. PIK3CD varients caused immunodeficiency in patients is a good example. No one would deny the association between human genomic stability and human immunity efficiency. However, many would raise doubts that our genomic mutations are the sole factor for disruption or failure of our immunity against certain diseases. I’d rather say that mutational changes in human genome are critical for causing our immunity compromise. There are more or less 20,000 protein coding genes and several thousand non-coding RNA genes in our genome. Yet we by far know very little about the biological functions of most of them. We need a lot more research to provide scientific evidence as proof that the versatile capability of human immunity is largely determined by human genomic stability.