Immunosuppressant: Drugs that inhibit the function of the immune system.

Asthma: In simple terms asthma refers to increased responsiveness of lower airways to multiple stimuli. It can be acute - when it lasts for a short period or chronic- when it lasts for days.

Cystic fibrosis: A common hereditary disease in which exocrine (secretory) glands produce abnormally thick mucus. This mucus can cause problems in digestion, breathing, and body cooling.

Leukemia: Cancer of blood-forming tissue.