Posts Tagged ‘CD4’

HIV / AIDS: Biology, Statistics, Risk Factors, Symptoms, Genetics, Tests

May 11, 2010

About HIV/AIDS

Human immunodeficiency virus (HIV) is a retrovirus that can result in acquired immunodeficiency syndrome (AIDS). Nine out of ten untreated individuals with HIV will develop AIDS in 10-15 years or sooner after acquiring the disease. With anti-retroviral treatment, patients have an increased life expectancy. Without treatment, patients usually die within a year.

AIDS is now considered to be pandemic. Between 1981 and 2006 it is estimated that 25 million people died from AIDS. In 2007 worldwide statistics show the following statistics:

  • 330,000 children died from AIDS
  • 2.1 million people died from AIDS
  • 33.2 million people lived with AIDS.

Over 75% of those deaths originated in sub-Saharan Africa.

The immunodeficiency affects every organ of the body. Certain conditions are more likely in a person with HIV including:

  • bacterial infections
  • cervical cancer
  • fungal infections
  • gastrointestinal infections
  • lymphomas
  • parasitic infections
  • pulmonary infections
  • tumors and malignancies
  • viral infections.

Symptoms develop from the body’s lack of having a regularly functioning immune system. Symptoms include:

  • chills
  • fever
  • sweats
  • swollen glands
  • weakness
  • weight loss.

Research has now determined that some individuals have HIV genetic resistance. Other people are more susceptible to HIV/AIDS. The risk factors that increase one’s chance of getting HIV include:

  • anal sex
  • blood exposure
  • blood transfusion recipients between 1978 and 1985
  • intravenous drug users who share syringes and/or needles
  • mother-infant transmission
  • needle stick injury
  • oral sex
  • people who have had multiple sex partners
  • people who have had sex with a man who has had sex with another man
  • sexually transmitted diseases (STD)
  • unprotected sex.

The Biology of HIV/AIDS

The human immunodeficiency virus attacks all the organs of the immune system. These include the CD4+ T cells. AIDS leads to failure of the entire immune system because CD4+ cells normally protect the body from infections. Without them opportunistic infections attack the body and can cause death.

HIV is spread from individual to individual by transfer of body fluids. This occurs by having unprotected sexual intercourse, by sharing needles or from mother to child. Infected fluids include:

  • blood
  • breast milk
  • pre-ejaculate
  • semen
  • vaginal fluid.

The Genetics of HIV/AIDS

HIV resistance is an inherited trait in about 1% of the white population, but it is rare in the African and Asian populations. This genetic disease resistance was first discovered when doctors realized that a small percentage of individuals who screened positive for HIV did not get AIDS. Chemokine coreceptors (CCR) were found to be responsible for suppressing infection. Researchers later found that people with a defective CCR5 gene are more resistant to HIV-1.

AIDS and genetic resistance research had determined that a deletion of a portion of the CC-CKR-5 gene makes the gene inaccessible to the virus. Some populations have a higher percentage of individuals with this mutation. This means that this mutation has a more recent origin.

Interpreting Your Genetic Test Results

DNA test results will determine if an individual is susceptible to HIV/AIDS or not. If one has the mutation in the gene that makes one resistant, it can be passed on to children. Those who are homozygous, or have two genes that are defective, are extremely resistant to the disease. Even though some people have a resistance to HIV, this virus has a very short replication cycle and can mutate within a short period of time. This means that even if an individual has a mutation in this gene, it does not mean that they will not get the disease.

If an individual’s genetic test results determine that they lack the “resistance” gene, this does not make the individual more susceptible to the disease than the general population. It just means that they must be careful and make the correct lifestyle choices.

 Frequently Asked Questions about HIV/AIDS Resistance

  • How safe is the blood supply in the United States?

The blood supply is the safest in the entire world. HIV testing began in 1985. All blood that was donated after this time has been HIV free. Additional testing has been added since this time. When blood has been identified as being infected, it is discarded.

  • Why is it so difficult to suppress AIDS?

The AIDS virus mutates at such a rapid rate that it is difficult to keep up with it. The best treatment at the time may be able to suppress most of the virus, but since it replicates so rapidly, at least some of the virus has become immune to the treatment.

  • Why do treatments sometimes fail?

Powerful combinations of cocktails exist to attempt to suppress AIDS. One of the reasons these treatments fail to work is the noncompliance of the patient to taking the drugs. Side effects may be unpleasant, dietary restrictions may be difficult and the act of taking dozens of pills may be daunting. If a patient does not take a dose, it could allow drug-resistant mutants to replicate and take the system over.

Recent News on HIV/AIDS Resistance

More recent research has determined that two separate genes, KIR3DL1 and HLA-B*57, are involved in resistance to AIDS. If an individual inherits a version of these genes, they might be more resistant to getting AIDS. The mechanism has not yet been explained, but this is good news.