People Living with HIV

AIDS, Acquired Immune Deficiency Syndrome, is caused by HIV, Human Immunodeficiency Virus. HIV does not cause symptoms directly, but when the virus enters the body, it attacks "CD4 cells" (white blood cells and macrophages) in the body's immune system, weakening the immune system and its ability to repair damage on its own. 

At this time, some diseases that pose no threat to the uninfected, such as Pneumocystis pneumonia, can take advantage of this situation and turn the HIV patients into AIDS patients. Although there is still no cure for AIDS, the treatment methods adopted in Hong Kong have greatly increased the life expectancy of AIDS patients. HIV can be present in a variety of body fluids of an infected person, including semen, blood, vaginal secretions, prostate secretions, and breast milk, and an infected person can spread HIV to others through exposure to these body fluids. The virus levels in saliva, sweat, tears, and urine are very low enough to constitute an infection. As people with HIV can look like normal people, HIV antibody testing can only be used to determine whether they are infected.

CD4 changes in HIV infection

CD4 changes in the initial stage of HIV infection will rapidly replicate in large numbers after infecting the human body. Up to hundreds of thousands or even millions of viral genes can be detected in each cubic millimeter of blood. Therefore, CD4 also undergoes a process of plummeting, and some patients can have CD4 below 200.

HIV infection -  asymptomatic period

After that, the immune system begins to produce specific antibodies and immune effector cells against HIV. Within a few months to half a year, the virus level in the blood will drop by several orders of magnitude, and then stabilize at the level of several thousand or tens of thousands, and CD4 will also gradually returns to normal or near-normal levels in most infected individuals without treatment. HIV infection has been effectively controlled, and the disease has entered the asymptomatic stage from the acute stage. During the asymptomatic period, as the immune system cannot completely clear the virus, in the long-term fight with the virus, the immune system wins less and loses more. The CD4 of infected people in the asymptomatic period is between 350-800, and the average annual decline is 40-60.

AIDS onset

At a certain point of time, the immune system of the body is overwhelmed and cannot control the reproduction of the virus, and the amount of virus in the blood will rise significantly again, reaching the level of hundreds of thousands or even hundreds of thousands, CD4 will plummet again, and the condition of the infected person will be rapid. deterioration, and then the disease.

CD4 detection interval

The detection interval of CD4+ T lymphocyte quantification should be determined by the clinician according to the specific situation of the patient. It is generally recommended that asymptomatic HIV-infected patients with CD4 cell count >350/μl be tested once a year; for patients whose CD4+ T lymphocyte count is between 200-350/μl and who have not started antiviral therapy, test once every six months; For patients who have received ART, the test is performed every 3 months in the first year of treatment, and the patients who have been treated for more than 1 year and whose disease is stable can be tested every six months. For reference only, the specific time is determined by the clinician.

Normal standard for CD4 cells

CD4 cells in Chinese adults were detected at 395 - 1,263¹. After the infected person takes the medicine, if the treatment is effective, the immunity represented by CD4 will gradually recover, but this process is mostly fluctuating. Therefore, CD4 counts that differ by more than 30% between the two measurements are meaningful.

Understand the physical condition by the number of CD4 cells

The HIV virus can grow rapidly in the human body. Without proper treatment, the virus can quickly destroy the body's immune system, leaving the body vulnerable to opportunistic infections. To fight this virus, it is especially important to maintain and strengthen the body's immune system. In addition to regular check-ups, infected individuals undergo two special tests to monitor the number of CD4 cells and the number of viruses to monitor the functioning of the immune system. The results of the test can be used to decide when to start drug therapy, monitor efficacy, and assess the need for switching.

U=U concept

With the advancement of medicine, there are now drugs that can effectively control AIDS and help the infected return to normal life. The concept of U=U (Undetectable = Untransmittable) has been popularized by the medical community in recent years: that is, the infected person can control the amount of virus in the body with drugs, and after regular testing, if the virus is not detected in the body, it means that it is not infectious. However, many infected people have misunderstandings about medication, including thinking that there is no need to rush treatment if they have no symptoms, and the side effects of medication will affect their lives, etc., so they are discouraged from treatment.

Regular check-ups for HIV-infected persons

Fee: $3,900 (28 items)

Check-ups for HIV monitoring including,

Ref1: Clin Vaccine Immunol. 2013 Apr; 20(4):602-606.