The immune system is made up of specialized cells and proteins. Some of these specialized cells include white blood cells such as lymphocytes (B cells and T cells) and phagocytes (neutrophils, monocytes, and macrophages). White blood cells are produced in the bone marrow. The complement system is a group of proteins found in the blood that are critical in defense against infection. When the immune system is missing any of these parts, people are vulnerable to specific types of diseases.
1 Depending on the brand and the type of humidifier, the costs of a humidifier are going to range anywhere from as little as $15 to as much as $150.2  Generally, table top humidifiers are going to be less than $50 while larger humidifiers that work up to 2,000 square feet can cost up to $150. Depending on the brand and the type of humidifier, the costs of a humidifier are going to range anywhere from as little as $15 to as much as $150.
The machine I got is what is called a VPAP, it is a variable pressure machine, which means when you inhale, you get a higher pressure from the machine, and when you exhale, you get a lower pressure. Without insurance, the machine with a humidifier ( which I recomend you get) was around $2000. That does not include the cost of the mask and hose. I hate to tell you, but the sleep study they do to determine the pressures for your machine is more of a pain than the regular sleep study. They were constantly waking me up, adjusting pressures and such, it was a long night.