Immunology of Pregnancy Flashcards
What is fetal growth restriction associated with?
Increased risk of cardiovascular disease, diabetes and stroke
What is pre-eclampsia?
Hypertension that develops during pregnancy
Proteinuria
Oedema
When is pre-eclampsia most common?
- First pregnancies
Risk falls with subsequent pregnancies unless change of partner - Oocyte donation
What are the two sites of interaction between maternal immune cells and the trophoblast?
- Maternal blood in contact with syncytium
2. Invading trophoblast in contact with decidua
What does systemic immunity refer to?
Immunity between maternal blood in contact with syncytium
What does local immunity refer to?
Immunity against invading trophoblast in the decidua
What is the pathogenesis of pre-eclampsia?
- Extravillous trophoblast fails to invade decidua properly
- Inadequate conversion of the spiral arteries
- Altered blood supply to placenta
- Placenta stress
- Maternal systemic endothelial disease
What is the role of the decidua?
Allow the trophoblast to invade adequately and protect the underlying uterine tissue
What occurs where there is no decidua?
- Trophoblast invades through caesarian scar
- Ectopic pregnancies are dangerous
- Placenta acreta/percreta
Where is HLA-G expressed?
Trophoblast only
Which HLA varies from pregnancy to pregnancy?
HLA-C
Which leukocytes occur in the decidua?
- CD56bright natural killer cells
- CD14+ macrophages
- Dendritic cells
- T cells and B cells
When do NK cell levels increase?
Secretory phase of cycle due to progesterone
Remain high throughout pregnancy
How are NK cells regulated?
- Monitor MHC levels on cells
- Activated by stress and viral ligands
- Integrate activating and inhibitory signals
What are the three main types of receptor used by NK cells to monitor levels of HLA?
- KIR
- NKG2A/CD94
- LILRB1
What does KIR recognise?
HLA-C
What does NKG2A/CD94 recognise?
HLA-E
What does LILRB1 recognise?
HLA-G
What determines KIR recognition of HLA-C?
C1 or C2 epitope
Which chromosome carries the KIR locus?
Chromosome 19
Which chromosome carries the HLA-C locus?
Chromosome 6
Which KIR haplotype is protective?
KIR B
Even when fetus has C2
Which KIR haplotype is at risk?
KIRAA with C2
What combination of KIR and HLA increases the risk of pre-eclampsia?
KIRAA with C2
How does the maternal immune system change in pregnancy?
- Responses to viruses are altered (may be more severe with chickenpox and flu)
- Rheumatoid arthritis and MS symptoms improve
- Ankylosing spondylitis and lupus get worse
What are the two routes for infection to the fetus?
- Infection from maternal blood
2. Through the decidua
What are Hofbauer cells?
Fetal macrophages
