How do genes play a part in how your immune system functions?

Studies have shown that the immune response in the body is regulated at the level of genes especially the adaptive immune response.

The body has evolved their immune system to eradicate or reject some specific pathogens and cancerous cells by expressing the antigen-specific genes which raise the immune response which could be at both humoral or cellular level.

The example of allelic exclusion is the example of how gene expression controls the formation of antigen-specific antibodies due to the expression of different segment of a particular gene or mutated gene.

Thus, the immune response is controlled by genes.