Immunology Flashcards
What are the pathogenic antibodies in bullous pemphigoid?
Anti-Hemidesmosome
A 34 year old man has severe Crohn’s disease. His gastroenterologist wishes to start a biologic drug, infliximab. What infection should be ruled out before commencing the drug?
Tuberculosis
Monoclonal antibodies directed against TNF-alpha are associated with activation and dissemination of latent TB. TNF-alpha is vital for the control of TB infection in the lungs. If it is blocked, TB can grow unchecked. Hence, prior to starting treatment with an anti-TNF-alpha antibody, a mantoux test should be performed to exclude exposure to TB
What type of vaccine is comprised of a polysaccharide bound to a immunogenic toxin?
Conjugate
What antigen is injected intradermally as part of the mantoux screening test for tuberculosis?
Tuberculin Purified Protein Derivative
The size of induration is measured after 48-72 hours (not erythema)
> 5mm is positive in HIV or immunocompromised, > 10mm in IVDU or medium risk populations (including healthcare workers), > 155mm is positive in low risk populations
What is the target of the antibody P-ANCA?
Myeloperoxidase
= UC, Eosinophilic Granulomatosis with Polyangiitis, Primary Sclerosing Cholangitis or Microscopic Polyangiitis
What is the target of the antibody c-ANCA
Proteinase-3
= Granulomatosis with polynagitis
A 80 year old lady received 2 units of FFP 4 hours ago due to a severe nosebleed and an INR of 4.8 on admission.
She takes wafarin for a metallic heart valve. Over the last hour, she is beginning to feel short of breath, especially when lying down. She is hypotensive at 95/40 and SpO2 of 94% on 8L/min O2.
She is pyrexic at 37.8C.
What complication of blood transfusion is she suffering from?
Transfusion Related Acute Lung Injury
Transfusion related acute lung injury (TRALI) is due to the presence of leukocyte antibodies causing white blood cells to aggregate in the pulmonary circulation as it passes through in the blood. The disease is characterised by acute onset pulmonary oedema, dyspnoea, severe hypoxaemia and hypotension. Treatment is usually supportive with a good resolution within 2 days. However, severe TRALI may lead to acute respiratory distress syndrome.
A 21 year old woman reports weight loss, tiredness, diarrhoea and non-bloody offensive smelling stools. She has had three chest infections requiring antibiotics in the last three years. Blood tests are ordered and reveals a hypochromic, microcytic anaemia with low ferritin. Anti-TTG and anti-endomysial antibodies are negative. There are normal levels of IgG, IgM and IgE. No IgA is found.
What is the most likely cause of her gastrointestinal symptoms?
Particular caution should be noted in the diagnosis of coeliac disease, as the common autoantibodies that are used for diagnosis are of the type IgA (Anti-Endomysial and Anti-Tissue Transglutaminase).
Hence, in IgA deficiency (1 in 600 people), they may be falsely negative.
IgA levels should always be assessed at the same time when assessing for coeliac disease.
What hematological cells create a “respiratory burst” in order to kill phagocytosed pathogens?
Neutrophils
What immunomodulatory agent may be given to treat chronic granulomatous disease?
Interferon Gamma
What monoclonal antibody targets IL-17 and is involved in the treatment of psoriasis, psoriatic arthritis and ankylosing spondylitis?
Secukinumab
What is the main metabolite of azathiroprine?
6-Mercaptopurine
A patient is investigated for a primary immunodeficiency. Lymphocyte counts are normal. However, IgG and IgA are low. There is an excess of IgM. What condition is this patient likely to have?
Hyper IgM Syndrome (defective CD40L)
What is the inheritance pattern of reticular dysgenesis?
Autosomal recessive
A 34 year old woman was given a blood transfusion yesterday due to low haemoglobin. She is pyrexic with a fever of 38c and feels slightly under the weather. All other observations normal. Infusion site is unremarkable. What is the first line treatment of this complication of transplant?
Paracetamol
Febrile non-haemolytic transfusion reaction is the most common reaction to packed red cell blood products.
It is thought to be caused by white blood cells releasing cytokines such as IL-1 during storage.
Symptoms include a fever >38 in mild cases or a high fever >39 with chills and rigors in severe reactions.
Mild reactions are not a reason to stop treatment. It may be appropriate to slow the rate of transfusion, if time allows.
Paracetamol or other NSAIDs may provide symptomatic relief.
A 40 year old woman with Hashimoto’s Disease visits the GP for routine review of medication.
She reported feeling particularly tired recently and visited a private rheumatologist on the advice of friends.
The private rheumatologist ran an autoimmune panel of blood tests showing that she is positive for ANA, anti-TPO antibody positive and positive for rheumatoid factor. Other bloods were unremarkable except for low T3 and T4.
What condition is responsible for her symptoms?
Hashimoto’s thyroiditis
A 40 year old woman with Hashimoto’s Disease visits the GP for routine review of medication.
She reported feeling particularly tired recently and visited a private rheumatologist on the advice of friends.
The private rheumatologist ran an autoimmune panel of blood tests showing that she is positive for ANA, anti-TPO antibody positive and positive for rheumatoid factor. Other bloods were unremarkable except for low T3 and T4.
What condition is responsible for her symptoms?
Hashimoto’s thyroiditis
The paediatric SpR is called to review a 16 day old infant who is pyrexic and appears unwell. His umbillical cord stump is still present, non-purulent, red, tender and hot. He has a fever of 39C. Blood tests reveal a neutrophil count of 16 (normal range: 1.5-8.0) What primary immunodeficiency is this patient likely to have?
Leukocyte adhesion defieiency
What immune cell releases granzyme and perforin when activated?
T killer cells
CD8 is a co-receptor for the T cell receptor and recognises MHC class 1.
MHC class 1 is found on most nucleated cells and presents random intracellular peptides to CD8+ T cells.
If a T cell recognises a peptide-MHC class 1 complex, then the T cell activates and kills the target cell.
Please note: Simply writing “CD8” is not enough detail for the mark. CD8 is a cell surface protein. We use cell surface markers to classify T cells. Hence, CD8+ T Cells is acceptable - but CD8+ is not.
What lymphocyte lineage does cyclosporine predominantly inhibit?
T lymphocytes
Its a CALCINEURIN INHIBITOR
A 20 year old man is screened for primary immunodeficiencies by his GP after a number of recent, severe infections.
A full blood count was normal.
IgA Normal
IgM Low
IgG Low
What immunodeficiency is this patient likely to have?
Common Variable Immunodeficiency
Common Variable Immunodeficiency (CVID) is a diagnosis of exclusion in patients greater than 4 years old. The diagnostic criteria are:
Decrease in serum IgG and a decrease in one of IgM or IgA.
There is a lack of antibody response to antigens or immunisation
More than 4 years old.
Patients will have increased infections with bacteria such as Haemophilus, Strep (usually immunized against) and Staph. There is an increased rate of autoimmune conditions and malignancies. Treatment is with normal human IVIg for life.
An 9 year old boy has had recurrent chest infections and influenza like illnesses since joining primary school.
Blood tests reveal a low lymphocyte count, with very low B cells but normal T cell levels.
There as very low levels of IgM, IgA and IgG.
What immunodeficiency is this patient likely to have?
Bruton’s Agammaglobulinaemia
Bruton’s Agammaglobulinaemia is a rare X linked immunodeficiency caused by a mutation in the BTK gene, which codes for a tyrosine kinase required for B cell development. Patients with this condition suffer from recurrent infections, typically from Streptococcal or Haemophilus spp. It often does not manifest until after 6 months, when the child loses passive immunity from the mother when breastfeeding. There is a notable lack of lymphoid tissue (lack of tonsils and adenoids) or lack of lymphadenopathy during infections. There is a decrease in all immunoglobulins, though small amounts may be present. It can usually be managed by injections of normal human IVIg for life.
What assay is used as the first line test for HIV infection?
Enzyme Linked Immunosorbent Assay (ELIZA)
What antiretroviral drug is given as IV monotherapy during labour to prevent vertical transmission of HIV-1?
Zidovudine
What antigen does the immune system erroneously target in autoimmune thrombocytopenic purpura?
Glycoprotein IIb/IIIa
An prenatal autoimmune panel of bloods reveals positive anti-Ro antibody in the blood of a pregnant woman with SLE. What cardiological condition is her unborn baby at risk of?
Congenital Heart Block
What serine protease released by neutrophils causes hepatitis and emphysema in patients deficient in alpha-1 antitrypsin?
Neutrophil elastase
Neutrophil elastase is a serine protease released by neutrophils and can cause hepatitis and emphysema in patients deficient in alpha-1 antitrypsin, which is an inhibitor of neutrophil elastase.
What viral enzyme is predominantly responsible for the high mutation rate of HIV and other RNA viruses?
Reverse Transcriptase
How may mast cell degranulation be measured?
Tryptase
In skin prick testing, what is used as a positive control?
Histamine
