I have heard it commonly stated that closed cell memory foam or latex are the best for those with mite allergies, with latex having the added benefit of being "all natural" when it is not blended with synthetics.
But then I came across this study:
"Schei, M.A., Hessen, J.O., and Lund, E. House-dust mites and mattresses. Allergy. 2002; 57: 538–542"
It states the following:
"Despite considerable efforts to develop anti dust mite strategies, surprisingly few studies have evaluated the allergen content in different types of mattresses in everyday use. This study investigated the presence of mite feces (an indicator of mite allergens) in foam and spring mattresses. After adjustment for relevant confounders, the risk of finding mite feces was four times higher in foam compared to spring mattresses (odds ratio 4.0, 95% confidence interval (CI) 1.1–15.1), and eight times higher for the foam mattresses without cover (OR 8.1, 95% CI 1.8–36.9)."
So what is the right answer?