Blood Bank - Chap 9 (Uncommon Blood Groups)
XG (012) system
- 2 antigens = Xg^a and CD99 - gene coding for Xga is on X chromosome (seen more commonly in females than males, 89% f, 66% m) - little known about CD99
Landsteiner Wiener (016) System
- 3 antigens, common high-prev = LW^a, LW^ab; low prev = LW^b - phenotypic relationship between D antigen and anti-LW - LW antigens depressed during pregnancy, lymphoma and leukemia
Gerbich (020) Systme
- 6 high prev Gerbich antigens (Ge2, Ge3, Ge4, GEPL, GEAT, GETI) and 5 low prev - expressed at birth - some antibodies may be IgM but most are IgG - clinically significant -Anti- Ge2 = most common Gerbich antibodies - MMA test to determine if antibodies are clin sig
Scianna (013) System
- 7 antigens - resistant to ficin and papain and DTT treatment - antigens expressed on cord RBCs
Knops (022) System
- 9 antigens - high frequency - located on complement receptor 1 (CR1) - antibodies = IgG but clinically insignificant for HTR and HDFN -Anti-Kn(a) frequently found in multiply transfused ind. and multi-specific sera
HLA antigens on RBCs
- HLA class I antigens (HLA-A, -B, -C) present on all nucleated cells - mature RBCs are not nucleated and generally do not have detectable level of HLA antigens - not considered blood group antigen - antigens: Bg^a, Bg^b, Bg^c (detectable on mature RBCs)
Er - antibodies
- IgG reacting at antiglobulin phase do not fix complement - Er(a+) RBCs to patient with anti-Era = positive DAT but no HTR (not clinically significant) - patient with anti-Er3 = mild hemolysis (potential significance) - antiEra and Erb have postivie DAT in newborn but no clinically significant HDFN
Chido/Rodgers (017) System - CH/RG
- Not intrinsic to RBC membrane rather they are on the fourth component of complement (C4) and absorbed onto RBCs from plasma - high prevalence - destroyed by ficin and papain but resistant to DTT and glycine-acid EDTA - usually IgG and react weakly often to moderate or high titration endpoint (HTLA = high titer low avidity) - neutralization with pooled plasma used to ID antibodies - clinically insignificant
Alloantibodies to Scianna
- alloantibodies to Scianna antigens are rare and little is known about signficance - usually IgG and reactive at AHG - no reported HTR and only mild HDFN reported
Er collection
- antigens: Er^a, Er^3 - Er antigens resistant to DTT and enzyme treatment - Er antigens expressedon cord cells
Colten (015) System
- antithetical antigens = high prev: Co^a, low prev: Co^b - Co3 = present on all RBCs excep those of very rare Co(a-b-)
Anti-Sd(a)
- can naturally occur in Sd(a-) - IgM and reactive at RT - reactivity is small, refractile (shiny) agglutinates when view microscopically
Diego - Anti-Di^a/Di^b
- caused HTR and HDFN - sometimes IgM but usually IgG
Dombrok - Anti-Do(a) and Anti-Do(b)
- caused delayed HTRs but no clinical HDFN - usually IgG and react optimally with enzyme treated cells
Sd^a antigen (in 901)
- high prevalence carbohydrate antigen - antigen not expressed on newborns but in saliva, urine and meconium - Sd(a) = reduced in pregnancy - antigen found on 91% of RBC samples and Sd(a) substance is found in 96% of urine - clinically significant - Sd(a+) = soluble antigen in urine and in Guinea pig urine, neutralization of refractile agglutinates used to identify anti-Sd(a)
Diego (010) System
- named after first antibody maker in Venezuelan family during investigation of HDFN - DI 010 by ISBT - 22 antigens: 3 sets of high/low pairs of antithetical antigens = Dia/Dib, Qra/Wrb, Wu/DISK and 16 low prevelance
anti-LW
- reacts strongly with D+ RBCs - weakly (sometimes not at all) with D- RBCs from adults and not at all with Rh (null) - may appear as anti-D - autoanti-LW = common in WAIHA - No HTR or HDFN
Cost collection
- serologically similar to Knops System - not located on CR1 - 2 antigens: Cs^a and Cs^b
Distinguishing anti-LW from anti-D
- test with DTT- treated D+ RBCs - D antigen is not denatured by DTT but LW antigen is destroyed - D will react, LW will be neg
Colton - Antibodies
- usually IgG and enhanced with enzyme treated RBCs - Anti-Co(a) = single specificity and can cause HTR and HDFN - Anti-Co(b) = often with other specificities and caused HTR and mild HDFN - Anti-Co3 (rare) = reacts with all Co(a+) and Co(b+) RBCs has been reported to cause mild HTR and severe HDFN
XG - Anti-Xg(a)
- usually IgG, has not been implicated in HDFN or HTRs
Cromer (021) system
-16 antigens, 13 high prev & 3 low-prev - carried on decay accelerating factor (DAF, CD55), a complement regulatory protein - antibodies are usually IgG but do not cause HDFN but some cause HTRs
Dombrok (014) system
-3 phenotypes: Do(a+b-), Do(a+b+), Do(a-b+) varies in different popultions - High-prevalence antigens: Gy(a) (Dombrock null) and Hy. - resistant to ficin, papin and glycine-acid EDTA but sensitive to DTT
YT system - anti-Yt(a) and anti-Yt(b)
Anti-Yt(a) and anti-Yt(b) = IgG and stimulated by pregnancy and transfusion - Anti-Yt(a) can be reasonable immunogenic but Yt (b) is a poor immunogen
YT (011)System - Cartwright
Yt^a = high prevalence antigen Yt^b = low prevalence antigen -variably sensitive to ficin and papain, DTT and resistant to glycine-acid EDTA - developed at birth but are expressed weaker on cord than on adult RBCs - absent on people with PNH
ISBT 901 series
antigens represent those with a prevalence of more than 90% of random populations - high prev.
ISBT 700 series
prevalance of less than 1% of most random population - low frequence
Diego - Anti-Wr^a
relatively common antibody but need AHG to be detected and has caused severe HTRs
