A large amount of information on the
epidemiology and clinical course of HIV infection has been accumulated. Using
technology and artificial intelligence the antiretroviral drug therapies are
improving and change in most of the clinical manifestations are seen. Here we
highlighted the Clinical features of HIV-infection.
Transmission of HIV
There are three major ways of HIV transmission
from one person to another:
1.
Sexual contact
Data collected till now shows that the sexual
contact, both, ether between heterosexual couples or homosexual male partners,
is the most common way of HIV transmission.
2.
Mother to child HIV transmission
This type transmission is the major cause of
pediatric AIDS cases, mostly occurs in utero or at the time of birth and also
possible through breast feeding.
3.
Inoculation
Another most common mode of transmitting HIV is
inoculating a recipient with HIV infected blood or its related products. This
includes the most, sharing of needles by drugs abusers or in clinical setting
for transfusion of blood or blood products in laboratory screening in few
cases.
Clinical Progression of HIV Infection
By measuring the amount of HIV virus in the
plasma of patient and counting of CD4+ T blood cell we can follow the progress
of HIV disease.
1.
Acute phase of HIV syndrome
Nonspecific symptoms of infection in acute phase
of HIV syndrome characterized the period of viremia. It develops after 3 to 6
weeks of infection in 50% to 75% of infected adults. Plasma virus increases and
little reduction in number of CD4+ T cells, however after few weeks the amount
of CD4+ T cell turn normal. However, in many patients the infection remains
asymptomatic.
2.
The chronic phase
This phase of HIV syndrome of clinical latency
may proceed for years and the patient suffer from minor infections or remains
asymptomatic. During this period HIV will remain within the lymphoid tissues,
however the progenitors helps to replenish the reduction of CD4+ T cells. After
infection of 2 to 6 months the plasma virus concentration stabilizes at a
certain set-point, which varies among patients. The level of the viral
set-point and the number of blood CD4+ T cells are clinically useful predictor
of the progression of disease. HIV production stimulated by immune response to
other infections occurred in patients due to progression of the disease and
resulted into the destruction of lymphoid tissues accelerated. As we said
before, HIV gene replication can be boosted by stimuli that activate T cells,
such as a variety of cytokines and antigens. The innate immune system produces
TNF cytokines in response to microbial infections which are generally effective
against other microbes, causes its own destruction due to HIV. Once the blood
CD4+ T cell count fall below 200 cells/ mm3, HIV infection progress to invariably
lethal phase, known as AIDS. In other reservoirs viral replication accelerates
unchecked, dramatically rises HIV viremia. As CD4+ helper T cells are necessary
for both cell-mediated and humoral immune responses to variety of microbes.
Therefore, loss of these lymphocytes in AIDS patients make him susceptible to
variety of opportunistic diseases like neoplasms, HIV wasting syndrome
(cachexia), HIV nephropathy (also called kidney failure) and CNS (Central
Nervous System) degeneration (AIDS encephalopathy). Moreover, AIDS patients
also have viral etiology in most of tumors cases and its prevalence due to AIDS
reflects the lacking ability of HIV infected individuals to give befitting
immune response to oncogenic viruses. many of the tumors that arise in patients
with AIDS have viral etiology and their prevalence in the setting of AIDS
reflects an inability of the HIV-infected patient to mount an effective immune
response against oncogenic viruses. Cachexia frequently occurs in patients
having chronic inflammatory infections and may cause as a result of
inflammatory cytokines (such as TNF) effects on appetite and metabolism. During
AIDS neuronal damage by the virus may cause the CNS disease or causes due to
hidden in viral proteins such as gp120 and Tat, as well as the cytokines
effects expanded by infected microglial cells. The highly active recent
antiretroviral therapy has significantly reduced most of these opportunistic
infections, tumors and devastating consequences of HIV infections.
Though for the most severe cases our given summary of the clinical progression of HIV disease is true, but studies also show that the rate of progression of HIV infection is highly variable, and many times individuals remains long-term nonprogressors. But immunologic reasons behind the variable progression of HIV remain unknown. The recent highly active antiretroviral therapy has significantly changed the course of HIV disease and greatly reduced the prevalence of tumors (like Kaposi’s sarcoma) and severe opportunistic infections like Pneumocystis).