Difficulty: Intermediate to Advanced | Prerequisites: Lecture 12 notes on CHD and chronic disease; basic understanding of immune system components (T cells, NK cells, antibodies).
This lecture bridges immunology and psychology, covering how stress, emotions and relationships affect immune functioning, then applies those principles to HIV/AIDS, cancer, rheumatoid arthritis and Type 1 diabetes. It is one of the densest lectures in the course because it spans several disease categories and intervention approaches. You need the stress-disease framework from Lecture 12 and a basic grasp of what immune cells do. If you are unsure about T cells, NK cells or antibodies, a quick review of introductory biology will help.
Stress compromises immune functioning through multiple pathways, increasing vulnerability to infectious disease and worsening autoimmune conditions. HIV attacks helper T cells, progresses gradually after an initial spike, and is managed through HAART and behavioural interventions targeting adherence and safe-sex practices. Cancer results from DNA dysfunction and is influenced by stress, coping style and social support. Rheumatoid arthritis is autoimmune and stress-sensitive. Type 1 diabetes requires active patient involvement in insulin management, dietary control and exercise.
Natural immunity
The body's generalised, non-specific defence against pathogens. Think of it as the first line of defence that reacts the same way regardless of the invader.
Specific immunity
A delayed, targeted immune response to a particular invader, involving specialised cells and antibodies. In simple terms, the immune system learns to recognise and attack a specific threat.
NK cell cytotoxicity
The ability of natural killer (NK) cells to destroy virus-infected cells and tumour cells. Lower NK cell activity is associated with insecure interpersonal attachments and stress.
Cytokines
Signalling molecules produced by immune cells that regulate inflammation and immune responses. Stress predicts higher cytokine production in people who are already ill.
HAART (highly active antiretroviral therapy)
A combination of antiretroviral medications used to treat HIV. It reduces sexual transmission if initiated early, but must be taken regularly to be effective.
HIV (human immunodeficiency virus)
A virus that attacks the helper T cells and macrophages of the immune system, eventually leading to AIDS.
AIDS (acquired immune deficiency syndrome)
The advanced stage of HIV infection, diagnosed when the immune system is sufficiently compromised to allow opportunistic infections.
Rheumatoid arthritis (RA)
An autoimmune disease affecting the small joints of the hands, feet, wrists, knees, ankles and neck, causing pain, limited activity and dependency.
Type 1 diabetes
An autoimmune disorder with abrupt symptom onset, resulting from the destruction of insulin-producing beta cells in the pancreas. It likely has both genetic and viral triggers.
The immune system distinguishes between self and foreign material, then attacks and removes foreign invaders. Natural immunity provides a generalised defence against pathogens, while specific immunity is a delayed response tailored to a particular invader.
Assessing the functioning of immune cells directly
Assessing the production of antibodies to latent viruses
Assessing levels of immune system products
Using indirect measures
Different stressors require different kinds of immune defences. Mounting a maximally efficient immune response to any situation entails costs to other systems.
Health risks from impaired immunity:
Increased vulnerability to infectious disease
Stress predicts more severe illness and higher cytokine production among those already sick
Autoimmune disorders are affected by stress
Stress compromises immune functioning broadly. Depression is associated with decreased cellular immunity, prolonged inflammatory responses, delayed wound healing and sleep disturbance.
Lonely people have poorer health and are immunocompromised
People with insecure attachments show lower NK cell cytotoxicity
Chronic interpersonal stress predicts inflammatory activity
Psychosocial resources have protective effects. Social support can buffer against adverse immune changes in response to stress, and resources such as financial stability limit deterioration in immune functioning. Optimism has an important influence on stress-related distress and immune changes.
Relaxation mutes the effects of stress on the immune system. Interventions targeting relaxation have significant effects on both immune system function and broader health outcomes.
AIDS is spread through high rates of extramarital sex, lack of condom use and high rates of gonorrhoea. HIV attacks the helper T cells and macrophages of the immune system.
Rapid viral growth in the first few weeks, with infection spreading throughout the body
After 3 to 6 weeks, viral growth becomes gradual, compromising the immune system by killing helper T cells
This creates vulnerability to opportunistic infections, which leads to the diagnosis of AIDS
Highly active antiretroviral therapy is a combination of antiretroviral medications. It reduces sexual transmission if initiated early, but the drugs must be taken regularly to be effective.
HIV infection is associated with depression, bereavement and thoughts of suicide. There is significant stigma associated with AIDS, including negative reactions toward people with the condition. Interventions that reduce depression are beneficial.
Prevention centres around: getting tested, refraining from high-risk sex, using condoms and not sharing needles.
Education plays a key role:
Educating target populations about risky activity
Providing information about HIV infection and modes of transmission
Addressing false beliefs
Culturally sensitive interventions are more effective
Sexual negotiation skills are important in interventions with high-risk groups
Interventions focus on building self-efficacy for practising safe sex
Increasing motivation for at-risk groups to change risk-related behaviour
Programmes developed for adolescents warn about the risks of unprotected intercourse and help instil safe-sex practices. The stage model of behaviour change guides interventions to increase safe-sex practices. Interventions that address the norms surrounding sexual activity are needed.
CBT provides a guiding framework for interventions that reduce risk-related sexual behaviour, maintain adherence to medication and reduce viral load.
Factors that hinder adherence: stress, alcohol use and practical problems related to poverty.
Factors that support adherence: psychosocial resources, motivational training, social support interventions and text messaging reminders.
Interventions include changing sexual activity, reducing risky injection practices, providing information about AIDS transmission, needle exchange programmes and instruction on sterilising needles. Methadone maintenance treatments coupled with HIV-related education reduce the spread of AIDS.
Coping effectiveness training and perceiving control over a stressor are helpful
Written disclosure supports coping
Social support is tied to greater adherence and lower viral load
Family support helps prevent depression
Cancer results from a dysfunction in DNA, the cellular programming that controls cell growth and reproduction. Interventions help reduce risk factors and improve coping.
Causes, symptoms and treatment vary across cancer types
Many cancers have long or irregular growth cycles
Identifying precipitating or co-occurring risk factors is difficult
Particular types of stress may affect the onset and course of cancer
Absence of close family ties in childhood predicts some cancers
Absence of a current social support network worsens the course of illness
Women who are socially isolated are at greater risk of dying from cancer-related problems
Avoidance is tied to a more rapid course of the disease
Depression can progress the disease and exacerbate other risk factors
Progression may be related to denial or repressive coping strategies
Altered functioning of the HPA and sympathetic stress systems can permit cancer to flourish
Patients cope with physical limitations including pain, discomfort, fatigue and compromised nutrition. Treatment-related problems include organ removal in surgical treatment and side effects of chemotherapy. Nutrition therapy is recommended.
Cognitive-behavioural approaches to cancer-related problems are vital
Mindfulness-based stress reduction interventions help
Improving health behaviours is a major target
Writing interventions result in fewer symptoms and fewer medical appointments
RA affects the small joints of the hands and feet, wrists, knees, ankles and neck. It is brought on by an autoimmune process, and its main complications are pain, limitations in activities and dependency.
Stress plays a role in both the development and aggravation of RA. The role of the spouse is critical to successful disease management.
Treatment: aspirin, rest, supervised exercise, cognitive-behavioural interventions and mindfulness interventions.
Type 1 diabetes is an autoimmune disorder characterised by the abrupt onset of symptoms. It results from the destruction of insulin-producing beta cells of the pancreas. It may appear following a viral infection and probably has a genetic contribution.
Frequent urination and unusual thirst
Excessive fluid consumption and fatigue
Weight loss, weakness, irritability, nausea
Uncontrollable craving for food
Fainting
Can result in a coma if untreated
Glucose levels must be monitored and action taken when required. Active patient involvement in treatment is essential:
Regular insulin injections
Dietary control
Weight control and exercise
Adherence tends to be low because severe complications are not evident for 15 to 20 years and patients may fail to self-monitor blood glucose levels. Active coping strategies help manage the disease. Adherence improves when patients and physicians share treatment goals.
Adolescent patients face unique challenges. Restrictions inconsistent with normal development are imposed, and they may be stigmatised by peers. Parents might infantilise them or try to convince them they are normal. Psychologists and interventions can help improve adjustment and adherence.
Students sometimes think HIV leads to AIDS immediately. It does not. After rapid initial growth, viral replication slows for weeks to years before the immune system is sufficiently compromised for an AIDS diagnosis.
Students may assume cancer is purely genetic. Psychosocial factors, including stress, depression, avoidance coping and lack of social support, influence the onset and course of the disease.
Students often confuse Type 1 and Type 2 diabetes. Type 1 is autoimmune with abrupt onset and requires insulin injections. Type 2 involves insulin resistance and is managed primarily through lifestyle changes.
Know the difference between natural and specific immunity
Understand how stress compromises immune functioning (cellular immunity, inflammation, wound healing)
Be able to describe the progression of HIV infection from initial rapid growth through gradual T-cell destruction to opportunistic infections
Know what HAART is and the adherence challenges associated with it
Understand the psychosocial factors that influence cancer progression (avoidance, depression, HPA/sympathetic system alteration)
Be clear on the distinction between Type 1 and Type 2 diabetes
Know why adherence is low in Type 1 diabetes (delayed complications, failure to self-monitor)
Q: What is the difference between natural immunity and specific immunity?
A: Natural immunity is a generalised, non-specific defence against pathogens. Specific immunity is a delayed, targeted response to a particular invader involving specialised cells and antibodies.
Q: Describe the three stages of HIV infection progression.
A: First, rapid viral growth in the first few weeks with infection spreading throughout the body. Second, after 3 to 6 weeks, gradual viral growth that kills helper T cells. Third, vulnerability to opportunistic infections, leading to an AIDS diagnosis.
Q: How does depression affect immune functioning?
A: Depression is associated with decreased cellular immunity, prolonged inflammatory responses, delayed wound healing and sleep disturbance.
Q: Why is adherence to Type 1 diabetes treatment often low?
A: Because severe complications are not evident for 15 to 20 years, creating a disconnect between daily management and long-term consequences. Patients may also fail to self-monitor blood glucose levels.
Q: Name two psychosocial factors that influence the course of cancer.
A: Any two of: avoidance coping (tied to more rapid disease course), depression (exacerbates other risk factors), denial or repressive coping, absence of social support, social isolation.
The stress-immunity link builds directly on the stress physiology covered in earlier lectures and the stress-CHD relationship from Lecture 12. The role of social support in coping with HIV, cancer and chronic disease connects to the social support and cardiac rehabilitation material in Lecture 12. The psychosocial factors influencing cancer connect forward to Lecture 14's discussion of health disparities and the ecological model of health.
Immune system, natural immunity, specific immunity, NK cells, natural killer cells, cytokines, psychoneuroimmunology, stress and immunity, depression and immune function, HIV, AIDS, human immunodeficiency virus, acquired immune deficiency syndrome, HAART, antiretroviral therapy, helper T cells, opportunistic infections, safe sex, sexual negotiation skills, needle exchange, adherence, cancer, DNA dysfunction, avoidance coping, HPA axis, rheumatoid arthritis, RA, autoimmune, Type 1 diabetes, insulin, beta cells, glycaemic control, adolescent diabetes, PSY 320, health psychology