immune system: age related changes

clinical scenario: PJ (30)

#4

humoral immunity aging

1. # of antigen responsive B lymphocytes decreases 2. # of auto reactive B lymphocytes increases 3. overall production IgM decreases 4. production of antibodies to foreign antigens decreases 5. production of antibodies to self antigens increases

cellular immunity aging

1. # of memory T cells increases 2. # of naive T cells decreases 3. # of auto reactive T cells increases 4. activation/proliferation decreases 5. helper/cytotoxic activities decreases 6. interleukin 2 decreases 7. interleukin 6 and 10 - increases 8. recognition of MHC molecules decreases

pathological aging

1. aged related changes explain why certain infections - pneumonia, UTI, flu, infectious diarrhea, infectious endocarditis, tetanus more common and more deadly 2. age related changes explain why cancer is more prevalent in older persons 3. certain disease processes increase in frequency in the elderly - septic arthritis, shingles, CLL, reactivation, TB, Non-Hodgkins Lymphoma, infectious diarrhea

more things involved in normal aging

1. atrophy of thymus 2. decreased response to interleukin 2 3. decreased cell mediated cytotoxicity 4. T cells which "remember" antigens respond less quickly 5. fewer WBC available - less intense reaction 6. fewer antibodies produced, less able to attach the antigen

aging factors and immune system response

1. decreased nutrition, dehydration, poor absorption of nutrients, lack of activity increases the decline of the immune system 2. decrease activity levels, decrease metabolism, decrease absorption of essential elements and nutrients, decrease muscle mass cause decrease in immune system 3. increase susceptibility to infection within setting of compromised and aging immune system

immune senescence

1. develops insidiously 2. manifested during periods of physiologic stress 3. genetic, environmental, chronic diseases play a role in immune system dysfunction 4. results from dysfunction rather than exhaustion of system 5. reversible? DHEA, zinc, vitamin E, growth hormone, melatonin

normal aging (Cont)

1. increase anti-idiotypic - antibodies that attack other antibodies 2. decreased surveillance, vigilance, eradication of abnormal cells 3. aged T cells do not display CD28 needed for T cell activation; presence of CD69 lower 4. calcium deficiency halts signal transduction, fails to stimulate enzymes and inhibits production of cytokines 5. diminished IgM response

PT implications

1. must closely monitor patients, vital signs, symptoms 2. clinical signs and symptoms may be muted 3. fever and chills, usual hallmarks of infection, may be absent 4. clinicians must feel confident in calling physicians with any concerns 5. frequent early warning signs - sense of feeling unwell, change in mentation, fatigue, decreased appetite

management of immune system

1. new methods of vaccination 2. new methods of vaccine delivery 3. IL-2 to increase vaccine efficacy 4. encourage nutrition with reduced caloric intake 5. Vitamin E - antioxidant, protects lymphocytes from destructive free radicals 6. Zinc - deficiency causes impaired regulation of helper T cell activity and decreased cytokine production

PT

1. physical activity and exercise 2. exercise beneficial to immune system 3. resistance training - 3 set 10 reps X 10 weeks increases natural killer cells 4. graded weight training with machines and intensity of 1 RM 5. encourage vaccines 6. monitor response with patients with liver, renal, and other chronic comorbidities 7. basis of evidence for vaccination is ability of lymphocytes to develop memory and mount a specific and immediate response

normal aging

1. reduction in active stem cells in bone marrow 2. decreased ability of T cells to mature, fewer naive T cells 3. decline in T helper cells - thus decline in B cell activation 4. decline in mass of spleen 5. decline in lymphoid tissue - replaced with connective tissue 6. overall decline in immune response but increased auto immune response

aging immune system

1. viral infection with symptoms of common cold affects aged population differently than the younger 2. decreased antigen response 3. decreased naive T cells available 4. slowed clearance of virus from the body 5. increased risk of secondary infections 6. child, adult, aged adult time frames

Review (31)

distortion

clinical scenario (GH)

good nutrition but with reduced calories

clinical scenario (Beth)

her recovery time may include a secondary infection

clinical scenario (ES)

increased autoimmune antibodies

increase in autoimmune antibodies

less able to distinguish self from non self

macrophages which ingest and destroy antigens act more slowly

thus increasing in cancer in older person