Men's Health Education: In-depth Analysis of How HIV Damages the Human Immune System

How HIV damages the immune system and causes disease

The immune function of a normal human body refers to a specific physiological response of the body to "antigenic foreign substances" or "foreign components". The function of the immune system is to identify and eliminate antigenic foreign substances, thereby maintaining the physiological balance of the internal environment. Antigenic foreign substances include bacteria and some viruses. The first line of defense against bacterial and viral invasion in a normal human body is the skin and mucous membranes; the second line is the blood-brain barrier; and the third line is the human immune system.

The human immune system consists of two main categories: immune organs and immune cells. Immune organs include the thymus, bone marrow, lymph nodes, spleen, and tonsils. Immune cells include two types: T lymphocytes and B lymphocytes. T lymphocytes are responsible for the body's cellular immune function and include various subtypes. Based on their function, they can be divided into three categories: cytotoxic T cells, helper T cells, and suppressor T cells. Cytotoxic T cells, upon re-stimulation by antigens, can produce lymphokines, directly or indirectly killing the antigens. Helper T cells assist B lymphocytes in producing antibodies. Suppressor T cells reduce the function of helper T cells and inhibit antibody production. B cells are effector cells of humoral immunity. When antigens invade, B cells produce large amounts of antibodies to neutralize them, forming antibody complexes. With the help of macrophages, these complexes clear the antigens from the body. Under normal physiological conditions, the human immune system acts like a country's army and police, tirelessly patrolling every part of the body. Once it detects an invading force (bacteria or virus) that has breached one or two lines of defense, it immediately activates its immune system to react quickly, either killing or expelling the invading force. Furthermore, the human immune system is responsible for clearing mutated abnormal cells from the body, thus greatly reducing the chance of developing malignant tumors.

After HIV enters the body, it has a special affinity for T and B lymphocytes. The function of T and B lymphocytes damaged by the virus is quickly destroyed. The aforementioned functions of resisting the invasion of harmful microorganisms and clearing mutated cells can be completely lost, preventing the body from producing a normal immune response to the attack of harmful microorganisms, and thus failing to kill and expel harmful antigens. This immune dysfunction... The consequences of this damage include not only making it easier for harmful pathogenic microorganisms from the outside to invade, but also allowing a large number of opportunistic pathogens (bacteria that are not pathogenic in a normal immune state but become pathogenic when the immune function is compromised) to thrive and multiply, causing harm to the body. For example, Pneumocystis carinii pneumonia, common in AIDS patients, is caused by such opportunistic pathogens. Furthermore, weakened immune surveillance and clearance can allow a large number of mutated or malignant cells to grow rapidly and unchecked, a significant cause of tumor development. Therefore, most AIDS patients ultimately die from opportunistic pathogen infection and tumor development.

The Pathogenesis of AIDS

After initial HIV infection, as with other viral infections, there may be a brief period of viremia before antibodies appear. Patients may experience mild fever, sore throat, rash, and transient lymphadenopathy. These symptoms are often mistaken for a common infection and disappear quickly. Several weeks after HIV infection, antibodies can be detected in the blood... Anti-HIV antibodies are detected in serum, but at this stage, there may be no clinical symptoms. The antibodies persist in the serum, making the virus difficult to detect. After an incubation period of 5-10 years, the disease can progress to AIDS. At this point, various secondary infections or tumors may appear, and the HIV virus in the serum can be easily detected. As the disease progresses, the immune system weakens or even fails, and various opportunistic infections and tumors affect various systems of the body, ultimately endangering life.