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23 Cards in this Set
- Front
- Back
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Indicate which of the following components increase or decrease during pregnancy:
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WBC count,-increases slightly beg in second month and levels off during 2nd and 3rd trimesters
chemotaxis- decreased due to an increased number of PMNs- polymorphonuclear neutrophils monocytes and granulocytes- increased p 473. natural killer cells- normal in the 1st tri, then down regulated (decreased) in 2nd and 3rd tri and after delivery secondary to progesterone p475.- TCD4 cells-p.480 decrease progressively to term T-suppressor cells (TCD8)- remain unchanged - some reports indicate that ratios of TCD4 TO TCD8 decrease- but most reports indicate that the number of t helper decrease progressively while t supressor remains unchanged. However, T suppressor cell function may increase in late pregancy and suppress B cell function. p481 |
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Why are pregnant women more susceptible to fungal infection (yeast vaginitis)?
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PMN attatchement, ingestion, and digestion of Candida albicans is increased possibly secondary to the effects of HCG. Pregnant women have higher rates of fungal infection which may be secondary to the effects of estrogen on nutrient availablilty for fungal growth in the reproductive tract. estorogens alter mucosal barrier allowing for adherence of pathogenic and increase risk of colonization. Conversely, improved PMN antibody expression may enhance phagocyte recognition and destruction of antigen-antibody complexes. p 475.
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What is the role of pregnancy zone protein (PZP) in pregnancy?
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glycoprotein that is produced in preg and has an inhibitory effect on the inflammatory process. levels increase 100-200 fold during pregnancy. Inhibits phagocytosis, suppresses inflammatory responses and IL-2 function especially near the decidua-trophoblast interface. p 476
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Describe the changes in the complement system seen in pregnancy.
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Although complement system is activated in pregnancy, activation doesnt result in the rejection of the fetus. Changes begin at 11 wks gestation with an increase(due to greater hepatic synthesis) in both total serum complement and specific proteins of complement system- C2, C3, C3 split. These enhance chemotaxis and actions of immunoglobulins thru opsonization which in turn increase maternal defenses against bacterial invasion. Other protein fragments are decreased(C1, C1a, B, and D)Because these fragments are involved in activation of the complement system, through either classical or alternative pathway , activity of the complement system early in the immune response may be delayed during pregnancy. 477-480 (good tables on 478-479 u should review)
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What is the role of the TCD4 cell in non-pregnant adults
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Normally augment cytotoxic responses involved in graph rejection How does it’s role change in pregnancy?decreased number of these cells may help protect the fetus from rejection by the mother(481)
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T-lymphocyte (cell-mediated immune response) function decreases and this may increase the mother’s risk for ___ and ___ infections. 481
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viral
_micotic |
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7. Some studies show a decrease in IgG in pregnancy. What are the explanations for this decrease?
When IgG decreases then the mother is at risk for |
hemodilution of pregnancy, enhanced loss of IgG in the urine and the transfer of maternal IgG to the fetus in the last trimester. Decreases in IgG range from 30-40% after 28 weeks.
bacterial colonization with certain pathogens(streptococci). 481 |
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Is protection of the fetus from rejection a localized uterine response
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yes- p481 column 2 para 3- “protection of the fetus from rejections seems to be predominately a localized uterine response, although there are systemic responses mediated primarily by endocrine factors.
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What protects sperm from recognition as foreign by the maternal immune system?
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Sperm are MHC class I and II negative (MHC I or II is a major histocompatibility glycoprotein complex involved in cell mediated immunity- see overview of adaptive immunity p477), which protects them from recognition as foreign by the maternal immune system although sperm and seminal fluid carry antigens. In addition, seminal fluid has immunosuppressors. Exposure to paternal antigens on sperm and seminal fluid prior to pregnancy may lead to decrease responsiveness and maternal tolerance to paternal MHC antigens. 482
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What is it about syncytiotrophoblasts that may help to prevent maternal rejection of the fetus?
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After placenta is established 2 points of contact between mom and fetus are synctiotrophoblasts, and extravillous trophoblasts. Syncytiotrophoblasts is in direct contact with maternal blood and doesnt express Class I or II MHC antigens. The cytotrophoblasts has a non classic MHC 1 surface antigen, HLA-G , - which doesnt stimulate cytotoxic T cell response. HLA-G has a Fas/FAs ligand pathway for killing activated T cells and may help prevent maternal rejection of the fetus by inducing aptosis of activated maternal T cells. p482
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What are the pathogens that the fetus may be immune to because of the passage of maternal IgG across the placenta?
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(p. 484a)
Tetanus, diphtheria, polio, measles, mumps, GBS, E.coli, Hep B virus (HBV), Salmonella enterica, and other pathogens. |
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What are Hofbauer (macrophage) cells?
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The primary placental defense against viruses and bacteria that are capable of being transferred across the placenta
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What organisms may cross the placenta to the fetus?
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(p.484a)
Listeria monocytogenes, Treponema pallidum, HIV, parvovirus B19, rubella, Toxoplasma gondii, and cytomegalovirus (CMV). |
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How high may the WBC count go during labor? Why?
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(p. 484a)
25,000-30,000/mm - due to an increase in neutrophils, may represent normal response to physiologic stress |
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Postpartally, when does the WBC count return to normal?
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(p. 484b)
Within 4-7days |
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What are the immunologic properties of human milk?
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Overall breast milk boosts infant’s immune system to fight off bacterial and viral infections and helps protect against the development of allergies.
The details: - There are Leukocytes: ●Primarily monocytic macrophages (85-90%) ●Lymphocytes (10-15%) ○Similar concentrations of B & T lymphocytes found ■B lymphocytes produce IgA, IgG, and IgM ■T cells produce interferon (which prevents viral replication), macrophage migration-inhibiting factor (MIF), and other cytokines. ●Some neutrophils & epithelial cells - Antibodies against O & K antigens of several E. coli serotypes including K1 (associated with neonatal meningitis) - IgM levels highest in colostrum, decrease after 5 days and remain constant ~180days. - IgG levels are consistent for at least first 180days - Secretory IgA (sIgA) found in highest concentrations (90%) - highest in colostrum, fall until 12wks, then remain stable for 2yrs of lactation. ●Protects the IgA from proteolytic digestion in GI tract. ●Neutralizes certain viruses and bacterial enterotoxins, inhibits intestinal absorption of proteins and other macromolecules found in foods. ○May provide protection against development of allergies - C3 & C4 also contained in milk - Immunoglobulins found in milk may protect infant from diphtheria, pertussis, Shigella, Salmonella, poliovirus, and echoviruses. (p486) Lactoferrin (an iron-binding protien, restricts availablity of iron needed for E.coli & S.aureus growth), a-lactalbumin, + sIgA = 60-80% of total human milk protein - Lysozyme destroys cells wall of bacterias, enhances Lactobacillus growth. - Maternal T-cells in milk stimulate development of immune cells in newborn thymus (thymus gland of breastfed baby bigger than thymus of formula fed baby) -Mothers of preterm infants have increased levels of sIgA, lactoferrin, and lysozyme present in their milk (compared to mothers of term infants) which helps protect the preterm infant who is at higher risk for infection and development of sepsis, along with higher risk of developing allergies |
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What are the immunologic factors that have been implicated in spontaneous abortion?
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(p. 486b-487a)
- Activation of immune response secondary to microbial infection -Chlamydia, listeriosis, parvovirus B19, or toxoplasmosis - Exaggerated maternal immune response to trophoblastic invasion - Cytokine-induced failure of the ovary to produce sufficient progesterone - The presence of autoimmune antibodies such as antiphospholipid antibodies that interfere with placentation. |
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Inflammation and fever may led to preterm labor because _______.
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Fever can lead to dehydration causing increased uterine activity + elaboration of prostaglandins = initiation of labor.
● High temperature alone may lead to release of catecolamines and corticotropin-releasing hormone and increased uterine irritability. ● Vag & cervical organisms are linked to initiation of preterm labor - mediated via inflammatory cytokines which stimulate prostaglandin E2a production. |
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What are the factors that support an immunologic basis for preeclampsia?
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(p. 488b)
●Increased incidence in primigravidas or, in case of multiparas, a pregnancy with a new partner or different sperm donor ●Increase in pregnancies with a large placental mass (multiple pregnancies) or hydatidiform mole ●Decreased incidence in repeat pregnancies with the same father and consanguineous marriages ●Decrease with longer cohabitation with the father before pregnancy ●Presence of pathologic changes in the uterine vessels near the placental site that are similar to those with allograft rejection. |
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What are some specific alterations in the immune system seen in women with preeclampsia? (see article in required readings)
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(488pg)
●Further reduction of NK cell activity, ●More TCD8+ cytotoxic cells ●Decreased TCD4+ to TCD8+ ratio ●More immune complexes ●Increased levels of fibronectin ●Alteration in complement ●Increased levels of inflammatory cytokines (including TNF-a & IL-2 These changes increase the risk of vascular endothelial injury which appears to be the underlying mechanism that results in preeclempsia |
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Do women with rheumatoid arthritis experience improvement in their condition during pregnancy? Why?
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(p. 489a)
75% of women experience improvement during pregnancy. ●Th1 mediators are decreased during pregnancy. ●Changes in plasma levels of maternal humoral factors ●Depression of cell-mediated immunity ●Suppression of inflammatory reactions |
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Why is ABO incompatibility a relatively mild disorder compared to Rho(D) isoimmunization?
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(p. 490-491)
Antibodies of ABO system are primarily IgM, which do not cross placenta ●Fetus may have its own anti-A or anti-B antibodies that can neutralize maternal antibody. Rho(D) isoimmunization: occurs when Rho(D)-negative mother carrying an Rho(D)-positive fetus produces antibody against the D antigen on the fetal RBC ●D antigen (a potent antigen) is present in large amounts on fetal RBC, appears as early as 6wks gestational age, stimulates formation of IgG-type antibody and memory cells in mother. Very dangerous in second pregnancy |
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If ABO incompatibility and Rho(D) isoimmunization occur at the same time, the likelihood of Rho(D) sensitization is reduced. Why?
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There is a protective effect that reduces the likelihood of maternal Rho(D) sensitization.
●Naturally occurring maternal anti-A antibody destroys fetal cells entering maternal circulation before they can trigger the mother’s immune system to produce anti-D antibodies and memory cells ○No anti-D antibodies or memory cells formed so woman remains unimmunized. |
