immunodeficiency

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.

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.

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.

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.

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.

HIV stands for human immunodeficiency virus. HIV harms your immune system by destroying a type of white blood cell that helps your body fight infection. This puts you at risk for other infections and diseases.

AIDS stands for acquired immunodeficiency syndrome. It is the final stage of infection with HIV. It happens when the body's immune system is badly damaged because of the virus. Not everyone with HIV develops AIDS.

HIV is spread through certain body fluids from a person who has HIV. This can happen:

• By having unprotected vaginal or anal sex with a person who has HIV. "Unprotected" means not using condoms or medicine to treat or prevent HIV. This is the most common way that it spreads.
• By sharing drug needles.
• Through contact with the blood of a person with HIV.
• From mother to baby during pregnancy, childbirth, or breastfeeding.

Anyone can get HIV, but certain groups have a higher risk of getting it:

• People who have another sexually transmitted infection (STI). Having an STI can increase your risk of getting or spreading HIV.
• People who inject drugs with shared needles.
• Gay and bisexual men.
• Black/African Americans and Hispanic/Latino Americans. They make up a higher proportion of new HIV diagnoses and people with HIV, compared to other races and ethnicities.
• People who engage in risky sexual behaviors, such as not using condoms or medicine to prevent or treat HIV.

Factors such as stigma, discrimination, income, education, and geographic region can also affect people's risk for HIV.

The first signs of HIV infection may be flu-like symptoms:

• Fever
• Chills
• Rash
• Night sweats (heavy sweating during sleep)
• Muscle aches
• Sore throat
• Fatigue
• Swollen lymph nodes
• Mouth ulcers

These symptoms may come and go within two to four weeks. This stage is called acute HIV infection.

If the infection is not treated, it becomes chronic HIV infection. Often, there are no symptoms during this stage. If it is not treated, eventually the virus will weaken your body's immune system. Then the infection will progress to AIDS. This is the late stage of HIV infection. Because your immune system is badly damaged, your body cannot fight off other infections, called opportunistic infections (OIs). OIs are infections that happen more frequently or are more severe in people who have weakened immune systems.

Some people may not feel sick during the earlier stages of HIV infection. So the only way to know for sure whether you have HIV is to get tested.

A blood test can tell if you have HIV infection. Your health care provider can do the test, or you can use a home testing kit. You can also use the CDC Testing Locator to find free testing sites.

There is no cure for HIV infection, but it can be treated with medicines. This is called antiretroviral therapy (ART). ART can make HIV infection a manageable chronic condition. It also reduces the risk of spreading the virus to others.

Most people with HIV live long and healthy lives if they get ART as soon as possible and stay on it. It's also important to take care of yourself. Making sure that you have the support you need, living a healthy lifestyle, and getting regular medical care can help you enjoy a better quality of life.

You can reduce the risk of getting or spreading HIV by:

• Getting tested for HIV.
• Choosing less risky sexual behaviors. This includes limiting the number of sexual partners you have and using latex condoms every time you have sex. If your or your partner is allergic to latex, you can use polyurethane condoms.
• Getting tested and treated for sexually transmitted infections (STIs).
• Not injecting drugs.
• Talking to your health care provider about medicines to prevent HIV:
  • PrEP (pre-exposure prophylaxis) is for people who don't already have HIV but are at very high risk of getting it. PrEP is daily medicine that can reduce this risk.
  • PEP (post-exposure prophylaxis) is for people who have possibly been exposed to HIV. It is only for emergency situations. PEP must be started within 72 hours after a possible exposure to HIV.

NIH: National Institutes of Health

HIV stands for human immunodeficiency virus. It harms your immune system by destroying CD4 cells. These are a type of white blood cells that fight infection. The loss of these cells makes it hard for your body to fight off infections and certain HIV-related cancers.

Without treatment, HIV can gradually destroy the immune system and advance to AIDS. AIDS stands for acquired immunodeficiency syndrome. It is the final stage of infection with HIV. Not everyone with HIV develops AIDS.

The treatment of HIV with medicines is called antiretroviral therapy (ART). It involves taking a combination of medicines every day. ART is recommended for everyone who has HIV. The medicines do not cure HIV infection, but help people with HIV live longer, healthier lives. They also reduce the risk of spreading the virus to others.

HIV medicines reduce the amount of HIV (viral load) in your body, which helps by:

• Giving your immune system a chance to recover. Even though there is still some HIV in your body, your immune system should be strong enough to fight off infections and certain HIV-related cancers.
• Reducing the risk that you will spread HIV to others.

There are many different types (called classes) of HIV medicines. Some work by blocking or changing enzymes that HIV needs to make copies of itself. This prevents HIV from copying itself, which reduces the amount of HIV in the body. Several types of medicines do this:

• Nucleoside reverse transcriptase inhibitors (NRTIs) block an enzyme called reverse transcriptase
• Non-nucleoside reverse transcriptase inhibitors (NNRTIs) bind to and later change reverse transcriptase
• Integrase inhibitors, also called integrase strand transfer inhibitors (INSTIs), block an enzyme called integrase
• Protease inhibitors (PIs) block an enzyme called protease

Some types of HIV medicines interfere with HIV's ability to infect CD4 immune system cells:

• Fusion inhibitors block HIV from entering the cells
• CCR5 antagonists and post-attachment inhibitors block different molecules on the CD4 cells. To infect a cell, HIV has to bind to two types of molecules on the cell's surface. Blocking either of these molecules prevents HIV from entering the cells.
• Attachment inhibitors bind to a specific protein on the outer surface of HIV. This prevents HIV from entering the cell.

Pharmacokinetic enhancers are another type of medicine. They are sometimes taken along with certain other HIV medicines. Pharmacokinetic enhancers increase the effectiveness of the other medicine. They work by slowing the breakdown of the other medicine. This allows that medicine to stay in the body longer at a higher concentration.

There are also multidrug combinations, which include a combination of two or more different types of HIV medicines.

It's important to start taking HIV medicines as soon as possible after your diagnosis, especially if you:

• Are pregnant
• Have AIDS
• Have certain HIV-related illnesses and infections
• Have an early HIV infection (the first 6 months after infection with HIV)

You and your health care provider will work together to come up with a personal treatment plan. This plan will be based on many factors, including:

• The possible side effects of HIV medicines
• Potential drug interactions with any other medicines you take
• How many medicines you will need to take every day
• Any other health problems you may have

It's important to take your medicines every day, according to the instructions from your provider. If you miss doses or don't follow a regular schedule, your treatment may not work, and the HIV virus may become resistant to the medicines.

HIV medicines can cause side effects. Most of these side effects are manageable, but a few can be serious. Tell your provider about any side effects that you are having. Don't stop taking your medicine without first talking to your provider. There may be steps you can take to help manage the side effects. In some cases, your provider may decide to change your medicines.

HIV medicines are not just used for treatment. Some people take them to prevent HIV. PrEP (pre-exposure prophylaxis) is for people who don't already have HIV but are at very high risk of getting it. PEP (post-exposure prophylaxis) is for people who have possibly been exposed to HIV.

NIH: Office of AIDS Research

Your newborn infant has screening tests before leaving the hospital. There may be different tests depending on the state where you live. They include:

• Tests on a few drops of blood from pricking the baby's heel. The tests look for inherited disorders. All states test for at least 30 of these conditions.
• A hearing test that measures the baby's response to sound
• A skin test that measures the level of oxygen in the blood. This can tell if the baby has a congenital heart defect.

These tests look for serious medical conditions. If not treated, some of these conditions can cause lifelong health problems. Others can cause early death. With early diagnosis, treatment can begin right away, before serious problems can occur or become permanent.

If a screening shows that your baby might have a condition, the health care provider or the state health department will call you. It is important to follow up quickly. Further testing can verify whether your baby has the condition. If so, treatment should start right away.

NIH: National Institute of Child Health and Human Development

HIV stands for human immunodeficiency virus. It harms your immune system by destroying a type of white blood cell that helps your body fight infection. This puts you at risk for other infections and diseases.

HIV can spread in different ways:

• By having unprotected vaginal or anal sex with a person who has HIV. "Unprotected" means not using condoms or medicine to treat or prevent HIV. This is the most common way it spreads.
  • Anal sex is the riskiest type of sex for getting or spreading HIV. The rectum's lining is thin and may allow HIV to enter the body during anal sex.
  • During vaginal sex, HIV can enter the body through the delicate tissue that lines the vagina and cervix.
• Rarely, through oral sex with a person who has HIV.
• By sharing drug needles.
• Through contact with the blood of a person who has HIV.
• From mother to baby during pregnancy, childbirth, or breastfeeding.

About one in four people in the United States who have HIV are women. Women who have HIV have some different problems from men:

• Complications such as
  • Repeated vaginal yeast infections
  • Severe pelvic inflammatory disease (PID)
  • A higher risk of cervical cancer
  • Menstrual cycle problems
  • A higher risk of osteoporosis
  • A higher risk of heart disease, especially heart attacks
  • Entering menopause younger or having more severe hot flashes
• Different, sometimes more severe, side effects from the medicines that treat HIV
• Drug interactions between some HIV medicines and hormonal birth control
• The risk of giving HIV to their baby while pregnancy or during childbirth

There is no cure, but there are many medicines to treat both HIV infection and the infections and cancers that come with it. People who get early treatment can live longer and healthier lives.

Germs, or microbes, are found everywhere - in the air, soil, and water. There are also germs on your skin and in your body. Many of them are harmless, and some can even be helpful. But some of them can make you sick. Infectious diseases are diseases that are caused by germs.

There are four main types of germs:

• Bacteria are one-celled germs that multiply quickly. They may give off toxins, which are harmful chemicals that can make you sick. Strep throat and urinary tract infections are common bacterial infections.
• Viruses are tiny capsules that contain genetic material. They invade your cells so that they can multiply. This can kill, damage, or change the cells and make you sick. Viral infections include HIV and the common cold.
• Fungi are primitive plant-like organisms such as mushrooms, mold, mildew, and yeasts. Athlete's foot and yeast infections are common fungal infections.
• Parasites are animals or plants that survive by living on or in other living things. Malaria and head lice are infections that are caused by parasites.

There are many different ways that you can get an infectious disease, depending on the type of germ. They can include:

• Through direct contact with a person who is sick. This includes kissing, touching, sneezing, coughing, and sexual contact. Pregnant people can also pass some germs along to their babies.
• Through indirect contact, when you touch something that has germs on it. For example, you could get germs if someone who is sick touched a door handle, and then you touch it.
• Through insect or animal bites.
• Through contaminated food, water, soil, or plants.

Infectious diseases can cause many different symptoms. Some are so mild that you may not even notice any symptoms, while others can be life-threatening.

There are treatments for some infectious diseases, such as antibiotic, antiviral, antifungal and anti-parasitic medicines. But for other infections, such as some caused by viruses, you can only treat your symptoms while you wait for your immune system to fight off the germ.

You can take steps to help prevent many infectious diseases:

• Get vaccinated.
• Wash your hands often.
• Pay attention to food safety.
• Avoid contact with wild animals.
• Use a latex condom every time you have sex. If your or your partner is allergic to latex, you can use polyurethane condoms.
• Don't share items such as toothbrushes, combs, and straws.

Your liver is the largest organ inside your body. It helps your body digest food, store energy, and remove poisons.

There are many kinds of liver diseases:

• Diseases caused by viruses, such as hepatitis A, hepatitis B, and hepatitis C
• Diseases caused by drugs, poisons, or too much alcohol. Examples include fatty liver disease and cirrhosis.
• Liver cancer
• Inherited diseases, such as hemochromatosis and Wilson disease

Symptoms of liver disease can vary, but they often include swelling of the abdomen and legs, bruising easily, changes in the color of your stool and urine, and jaundice, or yellowing of the skin and eyes. Sometimes there are no symptoms. Tests such as imaging tests and liver function tests can check for liver damage and help to diagnose liver diseases.

HIV stands for human immunodeficiency virus. It harms your immune system by destroying a type of white blood cell that helps your body fight infection.

AIDS is the final stage of infection with HIV. It happens when the body's immune system is badly damaged because of the virus. Not everyone with HIV develops AIDS.

There is no cure for HIV, but there are many medicines to treat both HIV infection and the health problems and infections (called opportunistic infections, or OIs) that come with it. The medicines allow people with HIV to have long, healthy lives.

IIf you have HIV, you can help yourself by:

• Getting medical care as soon as you find out that you have HIV. You should find a health care provider who has experience in treating HIV.
• Taking your medicines every day.
• Letting your provider know if you get any new symptoms or health problems.
• Keeping up with your regular medical and dental care.This includes staying up to date with your recommended health screenings and vaccinations. Your provider can let you know which ones you need.
• Managing stress and getting support, such as from support groups, therapists, and social service organizations
• Trying to live a healthy lifestyle, including:
• Eating healthy foods.This can give your body the energy it needs to fight HIV and other infections. It can help you manage HIV symptoms and medicine side effects. It may also improve absorption of your HIV medicines.
• Getting regular physical activity. This can strengthen your body and immune system. It may also reduce the risk of depression.
• Getting enough sleep. Sleep is important for your physical strength and mental health.
• Not smoking. People with HIV who smoke have a higher risk of developing conditions such as certain cancers and infections. Smoking can also interfere with your medicines. Talk to your provider if you need help quitting smoking.
• Avoiding heavy drinking or taking illegal drugs. They can damage your liver, which means your HIV medicine may not work as well. They can also make it harder for your body to fight infections.
• Protecting yourself from OIs. Talk to your provider about medicines and vaccines that prevent certain OIs. Also, be careful to avoid exposure to contaminated food and water.

It is also important to reduce the risk of spreading HIV to other people. You should tell your sex partners that you have HIV and always use latex condoms. If your or your partner is allergic to latex, you can use polyurethane condoms.