Acquired Immune Deficiencies Flashcards
Contrast secondary/ acquired immunodeficiency with primary deficiency.
secondly is due to insufficiency of a supporting component or an external factor decreased immune function
Describe the ways in which DM leads to immunodeficiency.
diabetes can impair the function of cells involved in cellular and/or humoral immunity but the dysfunction of NEUTROPHILS is the most prominent (hyperglycemia makes PMNs dysfunction)
type 1 diabetics exhibit more immune dysregulation (autoimmune disease to begin with), co-existing vascular disease also contributes to infection (both neuropathy and cardiovascular compromise)
What diseases/infections are diabetics more susceptible to?
respiratory infections such as pneumonia and influenza
skins and soft tissue infections
infections with candida
mucormycosis infection (rhino pulmonary zygomycosis)
malignant otitis external due to P. aeurginosa
Describe why pregnant women are relatively immunocompromised.
“immune modulation”
pregnant women must be tolerant of foreign antibodies or risk rejecting the developing baby which puts them at increased susceptibility and severity of some infections
mechanisms of modulation include: progesterone (inhibits lymphocytic proliferation), uromodulin (inhibits B cell activity) and depressed T-cell responses
List some infections that pregnant women are more susceptible to.
Hepatitis A, B, E listeria campylobacter TB Malaria influenza herpesvirus chlamydia/GC
How does protein/calorie malnutrition cause immunodeficiency?
protein-calorie malnutrition is associated with impaired cellular and humoral immunity (globally infections are the primary cause of morbidity and mortality in malnourished)
(via global metabolic disturbances, low levels of leptin, def. in nutrients)
Describe the immune deficiency that develops with aging.
decrease of immune function with aging “immune senescence” includes decrease in size and function of the thymus, decreased in suppressor cell function and increase in auto-reacitivity
changes in lymphocyte development lead to reemergence of latent infections
How do trauma and critical illness cause depressed reaction of the immune system?
trauma and critical illness can cause massive release of inflammatory cytokines
burns are associated with massive protein loss as wellas disruption of physical barriers to infection
How does stress reduce immune function?
reduced natural killer cell activity
depressed lymphocyte mitogen responses
release of endogenous glucocoricoids
V. vulnificus is ___ times more likely to spread into the bloodstream in people with compromised immune systems, especially those with _______ _____ ____.
80x more likely, especially those with chronic liver disease
What GI conditions can lead lead to immunosuppression?
cirrhosis
end stage liver disease
protein losing conditions (IBD and celiac disease)
What are the mechanisms of immune suppression in liver disease?
shunting of portal blood reduces Kupffer cells ability to clear opsonized organisms
cirrhotic patients often have very low compliment level
reduced hepatic metabolism of endogenous glucocorticoids
What infections are common with ESLD?
sepsis, bacterial peritonitis (associated with ascites)
cryptococcal infection
candidate infection
infection with vibrio vulnificus
Which diseases are associated with hypogammaglobulinemia through loss of large amounts of serum proteins?
nephrotic syndrome IBD and celiac disease massive lymphedema peritoneal dialysis burns dermatitis
B cell or T cell deficiencies have been noted in which hematological conditions?
multiple myeloma
Waldenstrom’s macroglobulinemia
Chronic lymphocytic leukemia
well differentiated lymphomas
hodgkin’s disease
advanced tumors
Blood transfusion from a major-histocompatibility- unrelated donor has been clearly demonstrated to cause what?
immune suppressive with a greater risk of post-operative infections and cancer recurrence or metastasis, although the effect is NOT seen with leukocyte depleted blood
List viral infections that modulate the immune system and list how the modulate.
measles: T-cell lymphopenia, cutaneous anergy, diminished T cell proliferation and diminished antibody production
HTLV: can produce aggressive T cell malignant neoplasm and severe immune defects and multiple opportunistic infections
herpesviruses ie. CMV: CMV in transplant patients places them at risk for other opportunistic infections such as PJP, aspergillosis and organ rejection
How do super antigens modulate the immune system?
infections associated with toxin producing staph and strep can bind simultaneously to MHC class II antigens and to non-antigen-binding region of T-cell receptor
this stimulates T cells which produce inflammatory cytokines leading to septic shock- like situation
after hyper activation T cell become anergic and can longer be activated
What are the effects of mycobacterial infection on the immune response?
they inhibit the ability of the infected cell to kill the invader and also prevent coordination of the immune response
this can lead to secondary infection and negative ppd despite active TB
How do parasites repress the immune system?
production of immunosuppressive factors, suppression of macrophage function and induction of suppressor T cells
Auto-immune conditions can lead to immune _________ as well as enhances ________.
autoimmune conditions lead to immune dysregulation and enhance the susceptibility of infection
e.g.: RA, SLE and granlomatosis polyangitis
Describes ways in which renal dysfunction can be immune suppressive.
uremia
ESRD
nephrotic syndrome: protein loss
dialysis leads to reduced T cell functor, diminished antibody production (poor vaccine response), deficient PMN function)
People on TNF inhibitors are at particular risk for what type of infection?
granulomatous infection including myobacterial infection and fungal infections
