MNSs System Flashcards

Question

What are the characteristics of anti-S?

Answer 1

Can be naturally occurring IgG Can cause HDFN and TRN RXN Can be enhance my incubating at room temp

Answer 2

IgG Can cause HFN and TRN RXN May be enhanced by lowering pH to 6.0

Answer 3

M+N-S-s- U- lack GPYB so no 'N'

Answer 4

Ficin control that reacts with all cells that reduced sialic acid residues Can be used to screen for U- donors because S-s-U- cells have reduced sialic acid

Answer 5

antibody is directed to a portion of M not present on patients own cells auto and DAT are negative Usually reacts at RT or 4C

Answer 6

RT, rarely 37 Not clinically significant for transfusion Rare antibody found in patients (N+ or N-) dialyzed with equipment cleaned with formaldehyde Trace formaldehyde can chemically modify the M and N antigens on the patient’s blood that goes through the dialysis equipment.

Answer 7

Nvg - made from the lectin Vicia graminea, which has anti-N specificity when diluted appropriately When not diluted will react with GYPB - 'N'

Answer 8

GYPB is less abundant on RBC's

Answer 9

S SGP is 1.5x more prevalent on the red cell than s SGP. Therefore, S+ rbcs have more ‘N’ than S-s+ rbcs. U neg cells (lack GPB) also lack ‘N’.

Answer 10

Destroyed by Papain/ficin like M and N Resistant to trypsin Destroyed by chymotrypsin

Answer 11

Antibody that can be made by N- U- individuals

Answer 12

``` High freq present on GYPA Rare deletion results in M- N- Ena- Wrb -phenotype Reduced sialic acid residue Glycine Soya will be positive in Ena- Present on cords DTT resisant ```

Answer 13

Trypsin Senstive - does not react with En(a+) cells treated with trypsin, ficin or papain.

Answer 14

Ficin sensitive - represents those Ena antibodies that recognize a ficin-sensitive (papain sensitive, trypsin resistant) determinant

Answer 15

Ficin resistant - represents those antibodies that react with a ficin-resistant (papain resistant, trypsin-resistant) determinant

Answer 16

IgM or IgG seen at IAT Can cause TXN RXN or HDFN (Transfuse Ena- units) Can be an autoantibody Ena neg individuals who make anti-Ena often make anti-Wrb (Ena required for Wrb expression) Anti-Ena is directed against different portions of GPr Extremely difficult to find Ena- blood. Look at siblings

Answer 17

Resistant to all chemicals U negative found in 1% of blacks U antigen is present on cord cells

Answer 18

IgG reacts at IAT Can cause TXN RXN and HDFN Can be auto antibody Most commonly found in blacks Not all Anti-U are compatible with U negative RBC’s (seen in U variants) Some can tolerate blood from Uvar donors Patients who are also N negative can make anti-U and anti-N (Anti-GPB)

Answer 19

``` 16% of serological S-s- have U var Uvar is a hybrid gene Weak U antigen is detected absorption and elution 23% are He+ Can make anti-U ```

Answer 20

Extremely rare phenotype (Mk is not a gene) Caused by GYP*01N allele that produces no GPA or GPB. Homozygous = Cells are M-N-S-s-U- ‘N’-, En(a-), Wr(a-b-) Heterzygous = Cells will express MNS antigens produced by the normal allele -For example, Mk/Ns will type M-N+S-s+.

Answer 21

Single amino acid change in GYPA produces low frequency antigen Intermediate between M and N antigens. Reacts with most anti-M and some rabbit anti-N, but negative with Nvg lectin. Often present with M1 antigen (see MN CHO section)

Answer 22

Single amino acid change in GYPA produces low frequency antigen Found more often among Swiss. Previously used as an adjunct in paternity testing. Anti-Mg is common. Antibody can be made in rabbits.

Answer 23

Single amino acid change in GYPB produces low frequency antigen Antithetical to ‘N’ – He positive cells do not express ‘N’ Positive in 23% Uvar

Answer 24

Dantu is found in blacks Sta is found in very low frequency, but seen in Japanese and Asians These are hybrid antigens Carry a protease resistant N which is probably ‘N’ Ficin-treated cells will react with Nvg lectin Anti-Dantu may be found in reagent anti-S

Answer 25

Rare in European and African ethnicity, but higher prevalence in Chinese (7%) and Thais (10%) Form of Hybrid of GPYB Anti-Mur causes HTR/HDFN and is the most common blood group antibody after anti-A/-B in Hong Kong and Taiwan. Screen cells used in Southeast Asian labs should include a Mur+ cell.

Answer 26

``` Abnormal glycosylation (sialic acid or GluNAc) on GPA resulted in 6 antigens, now grouped in a separate blood group collection called MN CHO Antigens: M1, Hu, Tm, Can, Sext, Sj ```

Answer 27

Low prevalence (0.5% W, 16.5% B), found only on M+ cells, but is not an enhanced M Anti- M1 made primarily by M- (and some M+N+) individuals Anti-M and anti- M1 are not the same. Some anti-M react only with M1+ cells Amino acids are same in M and M1 but there is abnormal glycosylation GlcNAc is substituted for NANA on 1st GlcNAc This in inhibits glycosylation of amino acids 3 and 4

Answer 28

Amino acids 1-5 look like N | Like M1 there is a GlcNAc substituted for the 1st NANA which inhibits glycosylation of amino acids 3 and 4

Answer 29

Abnormal glycosylation results in polyagglutination T is when both NANA are removed and just GalNAc-Gal are present Tn is where the terminal NANA and GAL are removed exposing the GalNAc Reacts with human anti-A