Immune System and Disorders

What is the immune system?

Your immune system is a complex network of cells, tissues, and organs. Together they help the body fight infections and other diseases.

When germs such as bacteria or viruses invade your body, they attack and multiply. This is called an infection. The infection causes the disease that makes you sick. Your immune system protects you from the disease by fighting off the germs.

What are the parts of the immune system?

The immune system has many different parts, including:

• Your skin, which can help prevent germs from getting into the body
• Mucous membranes, which are the moist, inner linings of some organs and body cavities. They make mucus and other substances which can trap and fight germs.
• White blood cells, which fight germs
• Organs and tissues of the lymph system, such as the thymus, spleen, tonsils, lymph nodes, lymph vessels, and bone marrow. They produce, store, and carry white blood cells.

How does the immune system work?

Your immune system defends your body against substances it sees as harmful or foreign. These substances are called antigens. They may be germs such as bacteria and viruses. They might be chemicals or toxins. They could also be cells that are damaged from things like cancer or sunburn.

When your immune system recognizes an antigen, it attacks it. This is called an immune response. Part of this response is to make antibodies. Antibodies are proteins that work to attack, weaken, and destroy antigens. Your body also makes other cells to fight the antigen.

Afterwards, your immune system remembers the antigen. If it sees the antigen again, it can recognize it. It will quickly send out the right antibodies, so in most cases, you don't get sick. This protection against a certain disease is called immunity.

What are the types of immunity?

There are three different types of immunity:

• Innate immunity is the protection that you are born with. It is your body's first line of defense. It includes barriers such as the skin and mucous membranes. They keep harmful substances from entering the body. It also includes some cells and chemicals which can attack foreign substances.
• Active immunity, also called adaptive immunity, develops when you are infected with or vaccinated against a foreign substance. Active immunity is usually long-lasting. For many diseases, it can last your entire life.
• Passive immunity happens when you receive antibodies to a disease instead of making them through your own immune system. For example, newborn babies have antibodies from their mothers. People can also get passive immunity through blood products that contain antibodies. This kind of immunity gives you protection right away. But it only lasts a few weeks or months.

What can go wrong with the immune system?

Sometimes a person may have an immune response even though there is no real threat. This can lead to problems such as allergies, asthma, and autoimmune diseases. If you have an autoimmune disease, your immune system attacks healthy cells in your body by mistake.

Other immune system problems happen when your immune system does not work correctly. These problems include immunodeficiency diseases. If you have an immunodeficiency disease, you get sick more often. Your infections may last longer and can be more serious and harder to treat. They are often genetic disorders.

There are other diseases that can affect your immune system. For example, HIV is a virus that harms your immune system by destroying your white blood cells. If HIV is not treated, it can lead to AIDS (acquired immunodeficiency syndrome). People with AIDS have badly damaged immune systems. They get an increasing number of severe illnesses.

Infection Control

Every year, lives are lost because of the spread of infections in hospitals. Health care workers can take steps to prevent the spread of infectious diseases. These steps are part of infection control.

Proper hand washing is the most effective way to prevent the spread of infections in hospitals. If you are a patient, don't be afraid to remind friends, family and health care providers to wash their hands before getting close to you.

Other steps health care workers can take include:

• Covering coughs and sneezes
• Staying up to date with vaccinations
• Using gloves, masks and protective clothing
• Making tissues and hand cleaners available
• Following hospital guidelines when dealing with blood or contaminated items

Infectious Mononucleosis

What is infectious mononucleosis (mono)?

Infectious mononucleosis (mono) is a disease caused by viruses.The most common cause is the Epstein-Barr virus (EBV). Mono is contagious, which means it can spread from person to person. It is common among teenagers and young adults, especially college students.

What causes infectious mononucleosis (mono)?

Mono can be caused by many different viruses. But it is most often caused by the Epstein-Barr virus (EBV). EBV is found all over the world. Most people get an EBV infection at some point in their lives, but only some of them will get the symptoms of mono. EBV infections often happen during childhood or when someone is a young adult. EBV infections in children usually do not cause symptoms. And when they do, it's hard to tell the difference between the symptoms of mono and the symptoms of other common childhood illnesses such as the flu. Teens and young adults who get EBV are more likely to have symptoms that are typical of mono.

EBV and the other viruses that cause mono are usually spread through body fluids, especially saliva (spit). This means that you can get it through kissing. That's why mono is sometimes called "the kissing disease." But you can also get these viruses if you share food, drinks, forks, spoons, or lip balm with someone who has mono. Other less common ways of getting an infection are through blood transfusions, organ transplants, and blood and semen during sexual contact.

What are the symptoms of infectious mononucleosis (mono)?

The symptoms of mono usually start four to six weeks after you get the infection. But they may start sooner in young children. The symptoms often develop slowly, and they may not all happen at the same time. They can include:

• Extreme fatigue
• Fever
• Sore throat
• Head and body aches
• Swollen lymph glands in your neck and armpits
• Rash
• Swollen liver, spleen, or both (these are less common symptoms)

Most people get better in two to four weeks. However, some people may feel fatigued for several more weeks. Occasionally, the symptoms can last for six months or longer.

How is infectious mononucleosis (mono) diagnosed?

Your healthcare provider may diagnose mono based on your symptoms and a physical exam. The exam will include checking to see if your lymph nodes, tonsils, liver, or spleen are swollen. In some cases, your provider might also order a mono test to confirm the diagnosis.

What are the treatments for infectious mononucleosis (mono)?

• Drinking plenty of fluids to avoid dehydration.
• Getting lots of rest.
• Taking over-the-counter medications for pain and fever. But don't give aspirin to children or teens because it may cause Reye syndrome. This syndrome is a rare, serious illness that can affect the brain and liver.

If you have severe symptoms, your provider may suggest additional treatment based on which organs in your body are affected by the mono.

Antibiotics don't treat viral infections, so they do not help with mono. Some people do get bacterial infections such as strep throat along with mono. In that case, you probably need antibiotics to treat the bacterial infection. But you should not take penicillin antibiotics like ampicillin or amoxicillin. Those antibiotics can cause a rash in people who have mono.

Mono can cause an enlarged spleen, which could rupture and cause a medical emergency. To try to protect the spleen, providers recommend avoiding intense exercise and contact sports until you fully recover (about a month).

Can infectious mononucleosis (mono) be prevented?

There is no vaccine to protect against mono. To lower your chance of getting or spreading mono:

• Don't share food, drinks, forks, spoons, or lip balm with anyone, especially if you or the other person has mono.
• Don't kiss someone if you or the other person has mono.
• Wash your hands often with soap and water.

Centers for Disease Control and Prevention

Kidney Transplantation

A kidney transplant is an operation that places a healthy kidney in your body. The transplanted kidney takes over the work of the two kidneys that failed, so you no longer need dialysis.

During a transplant, the surgeon places the new kidney in your lower abdomen and connects the artery and vein of the new kidney to your artery and vein. Often, the new kidney will start making urine as soon as your blood starts flowing through it. But sometimes it takes a few weeks to start working.

Many transplanted kidneys come from donors who have died. Some come from a living family member. The wait for a new kidney can be long.

If you have a transplant, you must take drugs for the rest of your life, to keep your body from rejecting the new kidney.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases

Legionnaires' Disease

What is Legionnaires' Disease?

Legionnaires' disease is a serious type of pneumonia caused by Legionella bacteria. The disease got its name when a group of people at an American Legion convention became ill with this type of pneumonia.

Legionella is found naturally in freshwater, such as lakes and rivers. It can also be found in soil. But people usually only get sick from it when if it grows and spreads in man-made water systems. These systems can include hot tubs, fountains, and the plumbing systems of large buildings, such as hotels or nursing homes.

Legionella can also cause Pontiac fever. This is a milder, flu-like illness that doesn't infect your lungs.

What causes Legionnaires' disease?

You usually can't get infected by drinking water that contains the bacteria unless you aspirate it (accidentally breathe the water into your lungs). The bacteria don't spread from person to person. Disease outbreaks happen when many people are exposed to the same water source that contains the bacteria.

Who is more likely to develop Legionnaires' disease?

Most healthy people who come in contact with the bacteria do not become sick. You are more likely to develop an infection if you:

• Are over the age of 50
• Are a current or former smoker
• Have a chronic (long-lasting) disease such as diabetes or kidney failure
• Have a chronic lung disease such as COPD or emphysema
• Have a weakened immune system due to a disease such as HIV or cancer or are taking medicines that suppress your immune system
• Live in a long-term care facility
• Have recently stayed in a hospital or had surgery requiring anesthesia

What are the symptoms of Legionnaires' disease?

The symptoms usually show up 2 to 14 days after you were exposed to Legionella bacteria. Most of the symptoms are similar to those of other types of pneumonia. But Legionnaires' disease may also cause gastrointestinal symptoms and mental changes.

The symptoms of Legionnaires' disease may include:

• Cough
• High fever
• Chills
• Headache
• Chest pain
• Shortness of breath
• Fatigue
• Nausea and vomiting
• Diarrhea
• Confusion

What other problems can Legionnaires' disease cause?

Legionnaires' disease can cause life-threatening complications such as respiratory failure, kidney failure, and sepsis.

About 1 out of every 10 people who get sick with Legionnaires' disease will die from complications of the illness.

How is Legionnaires' disease diagnosed?

To find out if you have Legionnaires' disease, your health care provider will probably order a chest x-ray to see if you have pneumonia. If you do have it, lab tests such as a urine or sputum test can check for the Legionella bacteria. Your provider may also order a blood test to see if you have been exposed to the bacteria.

What are the treatments for Legionnaires' disease?

If you have Legionnaires' disease, you will likely need care in a hospital. The treatment is with antibiotics. Most people will recover, especially if they were healthy when they got the disease. Getting treatment early can increase the chances of getting better.

Can Legionnaires' disease be prevented?

You can lower your risk of getting Legionnaires' disease if you:

• Clean all your water-related devices regularly. This could include portable humidifiers, water heaters, air conditioners, and nasal rinses.
• If you haven't used your faucets and showerheads for a week or more, flush them by letting the hot and cold faucets run for at least two minutes before use.
• Avoid exposure to water sources such as decorative foundations or hot tubs if you don't know how well they are maintained.
• Use windshield cleaner in your wiper fluid tank in your car instead of water.
• Ask about how well your buildings' water systems are maintained.

Centers for Disease Control and Prevention