Although CLA+ memory T cells from LDHhigh secreted more IL-13, IL-5 and IL-9 in response to HDM in vitro than those from LDHlow patients, both AD subgroups responded to HDM and produced significantly more IL-4, IL-5, IL-9, IL-13, IL-17A and IFN-γ—and IL-22 and IL-31 only in the LDHhigh group—compared to controls. Here, IL9 is linked to Alzheimer disease.