Are nanomaterials a threat to the immune system?

Nanoparticles can enter into the human body through several routes and interact with components of the immune system. This interaction leads to enhanced release of different cytokines that include both proinflammatory and inflammatory cytokines as shown by several laboratories. The use of different types of materials may have different effects on the immune system; for instance, cobalt and nickel nanoparticles have inflammogenic effects while hydroxyapatite crystals stimulate TNF alpha secretion from macrophages which subsequently activate other phagocytes. Nanoparticles used in cosmetics and skin care products cause low systemic toxicity on skin. Carbon nanoparticles produce allergic symptoms, while fullerene is useful in mitigating allergy. Thus, nanoparticles have immunomodulatory potential as these can stimulate or suppress the immune system. However, both the conditions are undesirable and the successful nanoparticle-based therapeutics should avoid immunostimulatory or immunosuppressive reactions to the nanomaterials once administered into the body. The interaction of nanoparticles with the immune system alters its bioavailability and prolongs exposure time. Therefore, more data should be generated through in vivo studies.