All pillows do have some mites regardless of the material the pillows are made of.
Dust mites are microscopic creatures which thrive in humid and warm environments and they also feed on dead skin cells, that are very abundant in bedding.
Dust mites are also a common allergen, but they don't transmit any diseases or bite.
Pillows provide for the perfect conditions for dust mites to flourish, due to the warmth, humidity and even the constant supply of dead skin cells.
Dust mites are also naturally present in most homes and can easily infest mattresses, pillows, bedding and other soft furnishings.
Dust mites themselves are not harmful, although the dust mites droppings are also a common allergen, which can trigger allergies and allergic reactions and even asthma symptoms in some people.
To minimize the dust mites presence and exposure to the dust mites you should use allergen proof pillow covers and wash pillowcases and bedding weekly in hot water of at least 130 F to kill the dust mites.
Pillows should also be replaced every 1 year to 2 years or even more frequently if you have allergies.
Encasing your pillows in allergen proof pillow covers can prevent the mites from entering and also reduce allergen exposure.