How does HIV cause immunosuppression?
HIV invades lymphocytes and changes the DNA of cells so that they stop working normally and only produce copies of the HIV virus itself. After multiplying, the virus destroys the infected lymphocytes and returns to the blood in search of others to continue their multiplication.
Over time, the number of viruses in the bloodstream becomes steadily increasing as the number of CD4 + lymphocytes decreases. This destruction process is very slow and gradual, allowing patients to remain asymptomatic for many years. This means that people can be carriers of HIV for a long time without necessarily developing the AIDS disease.
A patient is only considered as having AIDS when the HIV virus has attacked and destroyed such a large number of lymphocytes that the immune system is already weakened. With few viable lymphocytes, the body becomes more vulnerable to infections, becoming susceptible to various types of viruses, bacteria, fungi and even tumors.
The severity of the disease is in so-called opportunistic infections, which are those that take advantage of the weakness of the immune system to develop.
However, in some cases HIV can also cause symptoms. Soon after the contamination by the virus we can have a picture called acute HIV infection , which has nothing to do with AIDS. It is a picture similar to any common virus, which is caused by a reaction of the body to the presence of a new virus.
Acute HIV infection
We call acute infection by HIV the picture of viral infection that comes days after the patient has been contaminated by the virus.
A large number of signs and symptoms may be associated with acute HIV infection. Many of these symptoms are non-specific and also occur in other infectious conditions, especially respiratory infections with other viruses, such as colds, flu, mononucleosis, etc.
Most patients who become infected with HIV develop symptoms of acute infection. The problem is that the picture is so nonspecific, and in some cases so mild, that most patients do not remember having it.
The most common symptom of acute HIV infection is fever (38 ° C to 40 ° C), which occurs in more than 80% of cases.
They are also very common:
Pharyngitis without enlargement of the tonsils and without pus.
Red spots on the skin ( rash ) occurring 48 to 72 hours after the onset of fever and usually last between 5 and 8 days. This rash usually presents as rounded lesions, smaller than 1 cm, reddish, with discrete relief and distributed throughout the body, mainly in the thorax, neck and face. They may also involve soles of the feet and palms.
Enlargement of lymph nodes (inguinal) mainly in axils and neck.
Joint pain, muscle and headache .
In 10% of cases there may also be enlargement of the liver and / or spleen, oral, anal or genital ulcers, diarrhea and vomiting (which can lead to weight loss of up to five kilos).
Symptoms of Acute HIV Infection
Ulcers appear to be related to the entry point of the virus into the mucous membranes, similar to what occurs in syphilis .
There are also described cases of hepatitis , pneumonia and pancreatitis caused by acute HIV infection. In rare cases oral or vaginal candidiasis may also occur .
As can be noted, the symptoms of acute HIV infection are non-specific, common to several other diseases. It is very difficult to establish a diagnosis only by the clinical picture. Therefore, more important than the symptoms themselves is the time interval between the risk behavior (sex without condoms or sharing of needles) and the appearance of them.
Patients in the acute phase of HIV have very high viral loads and are therefore highly contagious at this time.
The picture of acute infection can last up to two weeks, then disappears and HIV is silently lodged in the body for many years. After the acute phase, the viral load (virus count circulating in the blood) drops and stabilizes at low levels.
Symptoms of AIDS
The end of the acute infection usually coincides with the positivation of the anti-HIV serology, that is, the blood tests for HIV research become positive.
Acquired immunodeficiency syndrome (AIDS or AIDS) is a picture of immunosuppression caused by low levels of CD4 lymphocytes, which favors the onset of opportunistic infections.
We call opportunistic infections those that take advantage of the fall in our immune system to attack us. Opportunistic infections exist not only in AIDS but also in transplant patients, chemotherapy, cancer, or any other condition that leads to immunosuppression.
To establish a diagnosis of AIDS, one must be infected with HIV and:
Have a CD4 lymphocyte count less than 200 cells / mm3; or
Pulmonary or tracheal candidiasis.
Candidiasis of the esophagus.
Invasive uterine cervix cancer .
Disseminated coccidioidomycosis (fungal infection).
Extrapulmonary cryptococcosis (fungal infection).
Intestinal cryptosporiasis (parasitic disease).
Cytomegalovirus (viral disease).
HIV encephalopathy (brain injury by HIV).
Herpes simplex chronic (over a month long) or disseminated.
Disseminated histoplasmosis (fungal infection).
Chronic intestinal isosporiasis (parasitic disease).
Kaposi's sarcoma (AIDS typical neoplasia).
Central nervous system lymphoma .
Infection spread by Mycobacterium avium complex (bacterial infection).
Disseminated tuberculosis .
Pneumonia by the fungus Pneumocystis carinii (also called Pneumocystis jirovecii ).
Recurrent pneumonia .
Recurrent multifocal leukoencephalopathy (viral disease that attacks the brain).
Sepsis by salmonella bacteria.
Cerebral toxoplasmosis .
HIV consumptive syndrome (HIV weight loss).
Any patient with one of the above diseases is likely to have some immune deficiency, as they are health problems that are not usually found in individuals with a perfect immune system. The diseases listed above are typical of patients with immunosuppression, not necessarily AIDS. Their presence, however, necessarily indicates HIV testing if there is no obvious cause for immunosuppression, such as immunosuppressive drug use or chemotherapy.
There is no single clinical symptoms of AIDS.
The most typical AIDS diseases are esophageal candidiasis, tuberculosis (which in pulmonary form may also occur in people without HIV), Kaposi's sarcoma, cerebral toxoplasmosis, P. carinii fungus and cytomegalovirus.
Immunosuppression in addition to facilitating the onset of infections also increases the frequency of malignant neoplasms. Cancers such as the uterine cervix become extremely aggressive and lymphomas are much more frequent in AIDS than in healthy people. Other tumors, such as Kaposi's sarcoma, are typically immunosuppressed, especially in homosexuals.
Treatment has come a long way in recent years, and most HIV-positive patients keep their CD4 levels high, preventing opportunistic infections from occurring. Patients are already diagnosed earlier and treatment is usually initiated before advanced stages of the disease.
But, attention, HIV still has no cure and still kills. It is therefore important to take the antiretroviral cocktail properly to prevent virus multiplication and destruction of CD4 lymphocytes.