The human immunodeficiency virus (HIV) is the causative agent for acquired immunodeficiency syndrome (AIDS). According to the World Health Organisation, an estimated 35 million people have died from HIV infection. At the end of 2016, another 1.8 million people were estimated to be newly infected with HIV. HIV is taking place on the scale of a pandemic and remains a major medical concern.
HIV infects cells that are a part of the body’s immune system, particularly CD4 T helper cells. CD4 is the name of a protein that is present on the cell surface of these cells. These cells are a crucial component for the body’s adaptive immune system. The adaptive immune system allows our bodies to fight off infections from microorganisms that we previously encountered (immunological memory). It is also involved in removing cancerous cells. Thus, HIV’s destruction of the body’s adaptive immune system greatly increases someone’s risk of acquiring infection, as well as their risk of developing cancer.
Complications from HIV infection commonly manifest during the advanced stage of infection i.e. AIDS. Owing to the broad scale of effects arising from a HIV infection, complications can occur in every single organ system in the body, which makes HIV/AIDS a complex disease.
Complications of HIV infection
Opportunistic infections: This term describes infection by microorganisms (bacteria, fungi, viruses) which normally do not pose a threat to healthy people, but can cause potentially serious infections in those whose immune systems have been severely weakened (e.g. AIDS patients). Opportunistic infections can be life-threatening in themselves, but they are also the cause of other complications, which can be just as dangerous, if not more so. One particular infection that is quite common in HIV-positive people is tuberculosis (TB). The risk of acquiring TB is estimated to be between 26 and 31 times higher in HIV-positive people compared to non-infected people.
TB itself is infectious even among healthy people, but HIV-positive people are also prone to unusual infections, such as toxoplasmosis and cryptococcosis. Toxoplasmosis is caused by a parasite called Toxoplasmosis gondii, and cryptococcosis is caused by the fungus Cryptococcus neoformans. Both of these infections can involve the central nervous system – which is particularly the case in AIDS patients – causing meningitis and encephalitis, which can be life-threatening. These infections can also contribute to some of the neurological symptoms occasionally observed in AIDS patients. Antibiotic treatments are generally available for treating opportunistic infections, but the persistent immunosuppressed status of AIDS patients will continue to place them at risk of infection, unless antiretroviral therapy is given to control the HIV infection. Damage caused by opportunistic infections may also be irreversible.
Cancer: Some of the cancers observed in AIDS patients are uncommon in non-infected people. One notable cancer is Kaposi’s sarcoma. Kaposi’s sarcoma is not actually caused by HIV, but by another virus called Kaposi’s sarcoma-associated herpesvirus (KSHV). However, the immunosuppressive effect of HIV infection allows KSHV infection to develop and cause Kaposi’s sarcoma. Kaposi’s sarcoma presents with purplish macules and nodules on the skin, especially around the trunk.
Hodgkin’s and Burkitt’s lymphomas are blood cancers which affect B cells. B cells produce antibodies and are also a part of the adaptive immune system like T cells. Hodgkin’s and Burkitt’s lymphomas are caused by Epstein-Barr virus infection.
HIV wasting syndrome: This syndrome describes unintended weight loss (10% or more of a person’s body weight). The exact cause of this syndrome is not well defined, but is likely to be the result of not just one factor, but a combination of factors in AIDS patients. Nausea and diarrhea are common in people with AIDS. Such symptoms may manifest as a result of opportunistic infections in the gastrointestinal tract (microsporidosis and cryptosporidosis). Since such symptoms lead to reduced food intake and increased loss of nutrients, they naturally lead to weight loss. Lipodystrophy, which involves the loss of subcutaneous fat, is also observed in HIV-positive people, but whether it is the result of HIV infection, or antiretroviral therapy, or both is still a matter of debate.
AIDS Dementia Complex (ADC): This is a neurocognitive disease associated with AIDS. It appears to be the result of infected immune cells causing the death of neurons. Symptoms of ADC are cognitive impairment (such as poor memory and concentration), speech difficulties, and motor dysfunction (tremors and poor balance).
HIV infection may not produce symptoms in the early stages, and can remain dormant in a person for many years until it is too late. Therefore, early testing of HIV infection is crucial to obtaining treatment early and delaying progression of the infection to AIDS. Antiretroviral therapy is able to control HIV infection and maintain a functional immune system – which is crucial for avoiding many of the complications of AIDS as we have seen above – as well as prolong a person’s life expectancy, and protect their quality of life.
Detecting HIV infection is quick and easy using our STD Rapid Test Kit, which uses the same method of detection as that of hospital laboratories worldwide. The kit requires only 1 – 2 drops of blood from a finger prick and gives you with a reliable and accurate result in 15 minutes. It is safe and easy to use.