What is Cancer?
• Extremely rapid cell growth & proliferation
• Dysfunction in part of DNA that controls cell Growth and reproduction
• Heterogeneous: more than 100 different types of Cancer
- The interactions among behavioural, neuroendocrine, and immunological
processes of adaptation.
The Immune System:
Surveillance system of the body
Primary function of the immune system is to distinguish between what it “self” and
what is foreign and then to attack and rid the body of foreign invaders
Profile of the immune system:
Natural immunity: involved in defense against a variety of pathogens.
- Largest group of cells involved in natural immunity is granulocytes, include
neutrophils and macrophages (both are phagocytic cells that engulf target
- Neutrophils and macrophages congregate at the site of an injury or infection and
release toxic substances.
- Macrophages release cytokines that lead to information and fever, among other
side effects and promote wound healing.
- Natural killer cells are also in natural immunity; they recognize non-self material
(such as viral infections or cancer cells) and lyse (break up disintegrate) those
cells by releasing toxic substances.
- Natural killer cells are believed to be important in signaling potential
malignancies and in limiting early phases of viral infections.
Specific immunity: slower, more specific than natural immunity.
- The lymphocytes involved in specific immunity have receptor sites on their cell
surfaces that fit with one of antigen.
- When they are activated, these antigen-specific cells divide and create a
population of cells called the proliferative response.
Natural and specific immunity work together, such that natural immunity contains
an infection or wood rapidly and early on following invasion of a pathogen, whereas
specific immunity involved a delay of up to several days before a full defense can be
Humoral and Cell-mediated immunity:
- Specific immunity is of two types:
- Humoral immunity is mediated by B-lymphocytes, which provide protection
against bacteria, neutralize toxins produced by bacteria and prevent viral
reinfection. - Cell mediated immunity, involving T lymphocytes from the thymus gland,
operates at the cellular level. Cytotoxic (Tc) cells respond to specific antigens
and kill by producing toxic substances that destroy virally infected cells. Helper
T (Th) cells enhances the function of Tc cells, B cells and macrophages by
producing lymphokines. Lymphokines also appear to service a counter
regulatory immune function that suppresses immune Activity.
General approaches of indicating immune functioning:
- Measuring the numbers of different kids of cells in the immune system by
looking at blood samples.
- Assessing the functioning of immune cells.
When indicators such as these suggest the immune system is working effectively, a
state of immunocompetence is said to exist.
When these indicators suggest that immune functioning may have been disrupted or
reduced below a normal level, a state of immunocompromise is said to exist.
Stress and Immune Functioning:
Many commonplace stressors can adversely affect the immune system.
Over 300 studies examine the relation of stress to immune functioning in humans.
Different kids of stressor create different demands on the body therefore show
different effects on the I.S.
Human beings likely evolved so that in response to sudden stress changes in the
immune system could take place quickly. Leading to wound repair and infection
Different types of stressful events make different demands on the body that are
reflected in different patterns of immune activity
- Intense short term stressors recruit cells that may help defend against wounds
Sympathetic activation in response to stress has immediate effects of increasing
immune activity, especially natural killer cell activity.
Stress-related changes in hypothalamic adrenocortical functioning have
Examples of Stress studies:
Study that relates to immunological changes is an investigation of the impact of
space flight on astronauts’ immune functioning:
11 astronauts flew 5 different space shuttle flights ranging from 4-16 days. Were
studied before and after launching/landing.
Space flight was associated with a significant increase in number of circulating
white blood cells and natural killer cells decreased.
At landing EPI and NOREPI increased substantially as did white blood cells.
Effects were stronger for astronauts who had been in space approximately a week
but in those who had experience long-term flight (~2 weeks) the effects were
attenuated. Evidence: stress of space flight and landing produces a sympathetic nervous system
response that mediates redistribution of circulating leukocytes but this response
may be attenuated after longer missions. (Stress of landing = muted by relief of
Research suggests that children and adults under stress show increased
vulnerability to infectious disease, including colds, flus, and herpes virus infections,
(cold sores, genital lesions, chicken pox, mononucleosis)
Among people who are already ill such as people with respiratory infection, stress
predicts more sever illness and higher production of cytokinesis
Disease that are influenced by proinflammatory cytokines are also potential health
risks associated with stress related immune changes (CVD, arthritis, other major
Immune system attacks the body’s own tissues, falsely identifying them as invaders
A.I. Diseases include more than 80 conditions and virtually every organ is
- Graves’ disease, (involving excessive production of thyroid hormone)
- Chronic active hepatitis (involving the chronic inflammation of the liver)
- Lupus *chronic inflammation of the connective tissue which can affect multiple
- Multiple sclerosis (destruction of the myelin sheath that surrounds nerves and
which produces a range of neurological symptoms
- Rheumatoid arthritis (immune system attacks and inflames the tissue lining the
- Inflammatory bowel disease (IBD, Crohn’s disease or ulcerative colitis) – causes
inflammation of the intestines; type 1 diabetes.
Nearly 80% of people who have these and other autoimmune disorders are women
Reason why women are so vulnerable might be hormonal changes relating to
estrogen modulate the occurrence and severity of symptoms.
Many women first develop symptoms in their 20s when estrogen levels are high
Another theory: testosterone may help protect against A.I., disorders and women
have a short supply of it.
Theory: during pregnancy, mother and fetus exchange bodily cells, which can
remain in the mother’s body for years. Although these cells are very similar to the
others own, they’re not identical and the immune system may get confused and
attack both the leftover fetal cells and the maternal cells that look similar
Since A.I. disorders are related group of conditions, it’s likely that one can be
suffering form one and then contracts another.
Genetic factors are implicated in autoimmunity
Negative Affect and Immune Functioning
Stress increases negative emotions such as depression or anxiety Clinic review relating depression to immunity found depression to be associated
with several alterations in cellular immunity – lowered proliferative response of
lymphocytes to mitogens, lowered NK cell activity, and alterations in numbers of
white blood cells. (Stronger among older people and sick)
The more depressed a person is the more compromise of cellular immunity is like to
Depressive symptoms can be associated with amplified and prolonged inflammatory
Stress, Immune Functioning and Interpersonal Relationships
Human and animal research suggests the importance of personal relationships to
Lonely people have poorer health and show more immunocompromse on certain
People with insecure attachments to others show lower NK cell cytotoxicity, which
may pose potential health risks
Marital Disruption and Conflict
Study results: women who had been separated one year or less had poorer
functioning on some immune parameters than did their matched married
Women separated or divorced that still continue attachments to their ex-husbands
show poorer immune functioning, depression and loneliness (results for men were
Partner violence tied to adverse changes in immune functioning
Short term marital conflict can have a neg. effect on the immune system
Even in long term marriages people are not protected against adverse
immunological effects of marital conflict
Adverse effects of marital problems and conflict appear to fall more heavily on
women than men
Positive behaviour during marital conflicts lead to steeper declines in stress
hormones with associated beneficial effects on immunity
Studies have found the stress of caregiving has adverse effects on wound repair,
defects in NK cell function and reactions to flu vaccine
Experience emotional distress (i.e. Anger or depression) is at a risk for adverse
effects on the I.S.
One can cope with effects and mitigate the distress
Severe and long-term stressors, such as those that result from caregiving (especially
in the elderly) may leave caregivers vulnerable to a range of health-related
Effects can continue even after caregiving activity has ceased
Protective Effects of Social Support
Perceived social support predicted greater NK cell activity Individuals with higher levels of social support had greater NK cell activity in tumor-
Individuals with small social networks and who experience loneliness show poor
antibody response to influenza vaccination
Coping and coping resources as moderators of the stress-immune functioning
These resources may moderate the relation between stress and immune
Optimism: many studies show links between optimism and enhanced immune
Self-Efficacy/Personal Control: less immunocompromise under stress. Changes can
come about in 3 ways:
- Perceived self-efficacy may reduce the experience of stress itself
- May reduce the tendency to develop depression in response to stressful events
- It may create some expectancy-based central nervous system modulation of
When people are exposed to controllable or uncontrollable stressors (noise) those
who perceive that they can control it show little change in immune parameters.
Those exposed to uncontrollable stressors are more likely to show adverse effects.
Interventions to Enhance Immunocompetence
- Emotional disclosure appears to enhance health and mood in individuals who
have suffered a traumatic event
- Written emotional disclosure on wound healing as stress is known to impair the
progress of wound healing
Relaxation: may mute the effects of stress on the I.S.
- Shows consistent benefits
- Massages decrease cortisol levels, increase leukocyte circulation
What is AIDS?
History of AIDS:
We don’t know when acquired immune deficiency syndrome (AIDS) first appeared
Began in Central Africa (maybe early 1970s)
Spread rapidly throughout Zaire, Uganda, central African nations, mainly because
origins were not understood
High rate of extramarital sex, little condom use, high rate of gonorrhea also
facilitated the spread of the AIDS virus in the heterosexual population.
Diseases made its way from Africa to Europe then Haiti and into the US
Estimated 33 million people are living with HIV/AIDS worldwide (most are women,
children and youth)
41% of new infections are among young adults and 60% of these are young women
~2/3 of these people live in sub-Saharan Africa; another 22% live in Asia and the
11 of every 1,000 adults ages 15-49 are infected with HIV. Over 60,000 Canadian residents have been diagnosed as HIV-positive since first care
13,000 Canadians have died of AIDS
15,000 may be unaware of their infection
Researchers predict 120 million deaths from AIDS by 2030. Unless major
investigation to treatment takes place
Epidemic is still in early stages and spreading to every part of the world
AIDS is the 6 leading cause of death worldwide
AIDS in Canada
First reported case of IADS in Canada was in 1982. In 2000, over 16,000 people in
Canada had AIDS and over 45,000 people were HIV positive
By 2006, 20,000 people had AIDS and 60,000 were HIV positive
The viral agent is a retrovirus, the human immunodeficiency virus (HIV), and it
attacks the helper T cells and macrophages of the immune system
The virus appears to be transmitted exclusively by the exchange of cell containing
bodily fluids, especially semen and blood
Period between contracting virus and developing symptoms is highly variable. From
a few months to a few years.
Therefore person may test HIV-seropositive but be free of AIDS and during the
asymptomatic period, pass on the virus to others
How is HIV transmitted?
Among drug users, needle sharing leads to the exchange of bodily fluids thereby
spreading the virus
Homosexual men, exchange of virus is tied to sexual practices (especially anal-
receptive sex, involving the exchange of semen without a condom)
Heterosexual population, vaginal intercourse is associated with transmission
(women more at risk than men)
How HIV infection progresses
Following transmission, the virus grows rapidly within first few weeks of infection
and spreads throughout the body
Early symptoms: swollen glands, fluid-like symptoms predominating
After three to 6 weeks: infection may abate, leading to a long asymptomatic period,
during which viral growth is slow and controlled
Amount of virus typically rises gradually, eventually severely compromising the
immune system by killing the helper T cells and producing a vulnerability to
opportunistic infections that leads to the diagnosis of AIDS
Early disease process: being to show abnormalities in their neuroendocrine and
cardiovascular responses to stress
- Highly active antiretroviral therapy (HAART) is a combo of antiretroviral
medications that has dramatically improved the health of HIV individuals
- So successful that in some cases HIV can’t be seen in the bloodstream
- Must take drugs faithfully, often several times a day or else they don’t work - In addiction, depression, a common condition among people with HIV is well
known to predict non-adherence and further threaten adherence with HAART
Researcher in Ottawa made intervention program to increase psychological
readiness for taking HAART:
- Readiness for change and coping strategies for dealing with barriers to
adherence were explored to maximize adherence success
- Socioeconomic factors, such as housing status
Who gets AIDS?
Two major at –risk groups for early Canadian epidemics = homosexual men and
intravenous drug users.
These groups still have largest numbers but other aboriginal people and other
minorities are increasingly at risk
In all populations adolescents and young adults are the most at risk because they’re
the most sexually active group, having more sex with different partners than any
other age group
~Half of all new infections reported worldwide occur within that age group
Evidence that individuals who have multiple risk factors are at increase risk for IDS
Canadian aboriginal women, a history of physical abuse or childhood sexual abuse,
and having one or both partners who went to residential schools was associated
with having AIDS
Women working in the sex trade now represent a common source of the spread of
Surveys show that the availability of antiretroviral therapeutic agents have relived
psychological distress I the gay community
Optimism regarding IDADS may have indirectly fuelled an increase in risk-related
behaviour because of the new treatments relieve worries about unsafe sex
Psychosocial impact of HIV infection
Depression is common with diagnosis of HIV most likely to occur among those who
have little social support who engage in avoidant coping and have more sever
Over longer term people cope with AIDS fairly well
Majority of people diagnosed with AIDS appear to make positive changes in their
health behaviors immediately after diagnosis:
Diet, More exercise, Quitting or reducing smoking, Reducing or eliminating drug use
Interventions that reduce depression are potentially valuable in the fight against
IADS because depression exacerbates many immune-related disorders
- Not disclosing HIV status or lying about risk factors (egg. Number of partners
one has had) is a major barrier to controlling spread of HIV
- Less likely to disclose HIV serosatus to sex partners also more likely to use