MLT GlobeBlood Banking: Other blood group systems – page 4
74 Blood Banking MCQs on Other blood group systems with answers and explanations.
Red cells that do NOT lyse when exposed to 2 M urea most likely have which phenotype?
The Kidd glycoprotein transports urea into the cell; normal cells swell and lyse in 2 M urea. Jk(a−b−) cells lack the transporter and resist lysis, making this a simple screening test for Kidd-null donors.
A cold-reacting anti-M shows stronger reactions after the plasma is:
Many examples of anti-M are pH-dependent and react better when the test is acidified. DTT would destroy IgM anti-M rather than enhance it.
A long-term hemodialysis patient has an anti-N-like antibody reacting with all cells. This is linked to reuse of dialyzers sterilized with:
Formaldehyde alters N-like structures on the patient's red cells, leading to anti-Nf. It usually reacts at room temperature and is of little clinical significance.
Women with the rare p phenotype often have an antibody linked to recurrent early miscarriage. This antibody is:
People with the p phenotype lack P1, P and Pk and make anti-PP1Pk, which can attack the placenta, which is rich in P and Pk. Anti-P1 alone is usually a weak cold antibody.
A donor has the dominant Lu(a−b−) phenotype caused by the In(Lu) gene (KLF1 variant). Which other antigen is typically weakened?
The In(Lu) type weakens Lutheran antigens and also depresses P1, i, AnWj and some Indian antigens. Kell, Duffy and Rh antigens are not affected.
The adult i phenotype (I-negative adult) in some Asian populations is associated with:
Some GCNT2 mutations that prevent I branching on red cells also affect the lens, so the Asian adult i phenotype is linked to congenital cataracts. CGD is linked to the McLeod phenotype.
Some Kidd antibodies are missed in the antiglobulin test when only anti-IgG reagent is used. Why?
Kidd antibodies often bind complement, and some examples are detected mainly through C3 on the cells. Polyspecific AHG containing anti-C3 may therefore detect them better.
The Kell glycoprotein is a:
Kell is a zinc endopeptidase that can activate big endothelin-3. Urea transport is the Kidd protein and chemokine binding is Duffy.
Antibodies to Mia (GP.Mur) are an important cause of hemolytic transfusion reactions and HDFN in:
GP.Mur is common in Taiwan, southern China and Thailand, so anti-Mia is a routine concern there, and screening cells may include Mia.
The Lutheran glycoprotein functions as a receptor for:
Lutheran/BCAM binds laminin, and this may increase adhesion of sickle red cells to vessel walls.
Dombrock antibodies (anti-Doa and anti-Dob) are best described as:
Dombrock antibodies are usually weak, often found with other antibodies, and typing reagents are scarce, yet they can cause hemolytic transfusion reactions.
The Gerbich-negative Leach phenotype, which lacks glycophorins C and D, is associated with:
Glycophorin C links the membrane to the cytoskeleton through protein 4.1; its absence gives elliptocytes. Vivax resistance relates to Duffy-negative cells.
The Jr(a−) phenotype, caused by variants of the ABCG2 transporter, is most frequent in people of:
Jr(a−) is found mainly in Japanese and other East Asians. Anti-Jra has caused HDFN and transfusion reactions.
Anti-Fy3, made by some Fy(a−b−) patients, differs from anti-Fya because it:
Fy3 lies on a part of the Duffy protein not cleaved by ficin or papain, so anti-Fy3 reacts with enzyme-treated cells, while Fya and Fyb are destroyed.