Why are people with AIDS so susceptible to Kaposi’s Sarcoma? I guess what I don’t understand is why someone with a suppressed immune system would be more prone to develop a cancer that is non-communicable?
You laboring are under the impression that an HIV+ person can be kept healthy simply by protecting him or her from contagion. While that may help, there are lots of processes already going on in the body that don’t involve “catching” anything. Cancer is a malignant growth caused by abnormal and uncontrolled cell division. A person with a compromised immune system may not be able to keep internally generated malignant cells in check.
This may be one reason why immune-suppressed patients are told to stop smoking & drinking… the fewer free radicals your body has to battle, the better.
I don’t think cancer is contagious anyway. I’ve worked closely with people with advanced AIDS-related KS and nobody ever told me to put on a bio-suit. If it were contagious, it would be more of an epidemic. I don’t think you can get cancer by being sneezed on, however the resident MDs will be along shortly to expand & correct where necessary.
Attrayant is right on. In addition to not fending off “foreign” things like germs, a deranged immune system is also unable to monitor and suppress cancer cells that arise from within.
Paradoxically, with respect to your specific question about Kaposi’s sarcoma (KS) at least, KS is secondary to an infection (herpes simplex virus 8 (IIRC)). People with HIV infection are unable to rid themselves of this cancer-causing herpes virus. That being said, HSV-8 is a recent discovery and I’m not sure it’s even known a) how it causes KS and b) What the prevalence and effect of HSV-8 is in the non-HIV population.
To be totally honest, I am not at all up on HIV and await other, more knowledgeable, comments. {b]Qadgop**, are you there?
Attrayant is right on. In addition to not fending off “foreign” things like germs, a deranged immune system is also unable to monitor and suppress cancer cells that arise from within.
Paradoxically, with respect to your specific question about Kaposi’s sarcoma (KS) at least, KS is secondary to an infection (herpes simplex virus 8 (IIRC)). People with HIV infection are unable to rid themselves of this cancer-causing herpes virus. That being said, HSV-8 is a recent discovery and I’m not sure it’s even known a) how it causes KS and b) What the prevalence and effect of HSV-8 is in the non-HIV population.
To be totally honest, I am not at all up on HIV and await other, more knowledgeable, comments. Qadgop, are you there?
… the board is at a crawl and I didn’t think the first one got through.
I wanted to add that people with HIV/AIDS also tend to develop lymphomas (cancers of the lymph nodes), especially so-called central nervous system lymphomas, cancer of the anus and cancer of the cervix.
Regarding cancer being associated with a defective immune system, this is not confined to AIDS. People who are born with defective immune systems have a high rate of cancer as do people who take drugs to deliberately suppress their immune systems (eg. to prevent rejection of a transplanted organ).
[nitpick]
KG posted:
The virus is referred to as human herpes virus 8 (HHV8) or Kaposi’s sarcoma-associated herpesvirus (KSHV).
[sub]I wouldn’t have brought this up, but an ID attending raked me over the coals during rounds for referring to the virus as Herpes Simplex Virus 8[/sub]
[/nitpick]
A very good review article describing the links between AIDS, HHV8 and Kaposi’s Sarcoma can be found here. The abstract is below.
Slight hijack.
Is KS still regarded as an “AIDS-defining illness”. There was talk some years ago of removing it from the list and I haven’t kept up to date with whether that happened or not.
choosybeggar: You are quite right. It’s not HSV-8, but HHV8. I actually think I knew that but got sloppy. And, I too have been raked over the coals by ID specialists. I share your pain.
reprise: According to the CDC, KS remains a defining illness. I suppose it’s possible that their web site (and sites that quote it) are out of date though.
According to this 1999 article from MMWR (a CDC publication)the list of AIDS defining illnesses is:
Pneumocystis carinii pneumonia
Kaposi sarcoma *
Esophageal candidiasis
Wasting syndrome
Mycobacterium avium complex
Pulmonary tuberculosis
Extrapulmonary cryptococcosis
HIV encephalopathy
Cytomegalovirus retinitis
Cytomegalovirus disease
Toxoplasmosis of brain
Chronic cryptosporidiosis
Recurrent pneumonia
Extrapulmonary tuberculosis
Chronic herpes simplex
Immunoblastic lymphoma *
Progressive multifocal leukoencephalopathy
Disseminated histoplasmosis
Burkitts lymphoma *
Other disseminated Mycobacterium
Primary brain lymphoma *
Pulmonary candidiasis
Disseminated coccidioidomycosis
Recurrent Salmonella septicemia
Chronic isosporiasis
Since some of these (eg pulmonary tuberculosis) occur even in non-HIV infected individuals, I believe that a positive test for HIV (viral RNA or p24) is needed as well to establish a diagnosis of AIDS. Also, IIRC, any HIV infected individual with a CD4 T cell count<400 meets the criteria for AIDS.
Back to the OP, though. The condiitons I marked with a * are all cancers. As KG said, the immune system is responsible for cancer surveillance. The decimated immune system of an individual with AIDS isn’t up to the task.
Additionally, many viruses (HHV8 for example)are implicated in the development of cancer. HIV infected individuals have a profound deficit in the ability to clear viral infections.
Yes, KS is still an “AIDS defining” condition, though with current therapies, it has become a rare diagnosis in this country. Another AIDS defining condition to add to ChoosyBeggar’s list is cervical cancer in women who also have confirmed HIV positive tests. Together with the immunosuppression from HIV, some cancers can be more aggressive. Cervical cancer and rectal cancer are usually caused by Human Papilloma Virus (HPV). It is not known why some people resolve this virus - HPV - and others develop cancer, but it is known that having HIV tends to help it develop.
Jill