This 2015 California rodent study found:

“Potentially pathogenic memory cells in lymph nodes and redistribution throughout normal and inflamed skin may help explain the generalized worsening of psoriasis reported in patients undergoing localized skin treatment with imiquimod.”

The opening sentence was:

“An attribute of adaptive immunity is the generation of memory cells that mount enhanced responses after rechallenge.”

Of course an immune system remembers – that’s part of its function.

When the subject is memory, let’s not disregard the multiple ways that our bodies remember our histories.

http://www.pnas.org/content/112/26/8046.full “Inflammation induces dermal Vγ4+ γδT17 memory-like cells that travel to distant skin and accelerate secondary IL-17–driven responses”