Clinical Immunology Flashcards
What chromosome are the HLA class 1 genes on?
Chromosome 6
Name the HLA class 1 groups
HLA-A, HLA-B, HLA-C
Name the HLA class 2 types
HLA-DP, HLA-DQ, HLA-DR
How man HLA alleles are there?
Hundreds. 1 in 70 million chance of having identical match.
Explain direct recognition in donor rejection
Donor APCs migrate to lymph nodes where they are recognised by t- cells that are stimulated by HLA proteins on APC cell surface = ALLOREACTIVE RECIPIENT T-CELLS
Explain indirect recognition in donor rejection
Proteins from donor tissue that are allelicly different to recipient are processed by recipient APCs
Explain SPUR
Serious
Persistent
Unusual/opportunistic
Recurrent
Infections in immune deficiency
What is associated with antibody defects?
Bacterial infection
What is associated with T cell defects?
Fungi, viruses and GvHD
What causes GvHD?
Happens in bone marrow transplantation-caused by T cells in BM
What infections are associated with phagocytic defects?
Abscesses
What is associated with terminal complement defects?
Neisseria
What is associated with classical complement defects?
Bacteria
What is an example of an antibody deficiency?
Agammaglobulinaemia/ brutans syndrome. Due to a mutation in a tyrosine kinase essential for B cell formation
What happens b-cells if yo lack tyrosine kinase?
B cells can’t be generated from immature B cells in bone marrow
What happens if you have an IgA deficiency?
Susceptible to infections
What causes hyper IgM?
Can’t undergo class switching. May lack cd40 expression of B cells that allows it to interact with t helper cells
What causes secondary antibody deficiencies?
Lymphoproliferative disease- leukaemias. Malnutrition
What causes transient hypogammaglobinaemia in infancy?
Transplacental transfer takes place in last 3 months of pregnancy- if baby is immature may lack IgG
What is the effect of di George syndrome/thymic hypoplasia?
Genetic defects that cause developmental defects of 3rd and 4th pharyngeal arches
What is the effect of di George on the parathyroids?
Hypocalcaemia
What is the effect of di George on the great vessels?
Congenital heart disease
What is the effect of di George on the thymus?
T cell deficiency - fungal, viral infections, graft vs host
What is the HIV target?
Infects helper T cells by binding to cd4 molecules
What is seroconversion illness?
10-15% of patients infected with hiv. Body produces antibodies to virus.
How is AIDS defined
By Th appearance of opportunistic infections
How many HIV viruses are there?
Two. Hiv-1 and his-2
AIDS is defined as a cd4 t Cell count of what?
Less than 200 microlitres
How does HIV escape detection?
Original detected by cytotoxic T cells but virus creates subtypes as it replicates so it escapes detection- as t helper cells are killed off- no adaptive immunity
What does HART stand for?
Highly active retroviral therapys
What is multiple kaposi’s sarcoma?
Cancer caused by herpes virus found in AIDS
What is severe combined immune deficiency? (SCID)
Inherited stem cell deficiency- lack of function in t and B cells
What is kostnanns syndrome?
Primary disorder of neutrophils. Reduced production
What is leucocyte adhesion deficiency?
Defect in production of integrins required for neutrophils to stick to blood vessels to get to infected tissues
Chronic granulomatous disease?
Primary disorder of neutrophils- can’t kill microbes- can’t generate reactive oxygen species required for killing bacteria)
What do defects in c1q, c2 or c4 cause?
Immune complex disease. Complement complexes can’t be cleared from spleen or liver - damages tissue eg kidney
What are iatrogenic causes of secondary immune deficiency?
Immunosuppressive treatment. Removal of lymphoid tissue
