Common RBC Antibodies
Red Blood Cell Antibodies
The red blood cell membrane contains a vast array of antigenic molecules which may induce the production of plasma antibodies. Currently there are some 330 known red cell antigens, categorised into 39 blood group systems (the first 9 of which contain the most commonly encountered antibodies)*. Immunisation is caused by exposure to 'foreign' red cells via pregnancy or transfusion though some plasma antibodies are naturally occurring.
Detection of these plasma antibodies is an essential part of the group and cross match process ensuring compatible blood for the recipient. Patients with plasma antibodies may require their transfusion to be delayed until compatible blood is found. This delay may be longer in patients who have multiple antibodies.
* ISBT Table of blood group antigens v.9.0, 12th July 2019.
The table below lists antigens to which antibodies are more commonly encountered.
|System Name||System Symbol||System Number||Number of Antigens||Major Antigens|
|ABO||ABO||001||4||A, A1, B|
|MNS||MN||002||49||M, N, S, s, U|
|Rh (Rhesus)||Rh||004||55||C, Cw, c, D, E, e|
|Kell||K||006||36||K, k, Kpa|
The table below lists antibodies to the more common antigens.
|Antibody||HDN||HTR||Approx. % Compatible||Notes|
|Anti-C||Yes||Yes||30||Anti-C is most often found in combination with anti-D and/or anti-E in rr individuals.|
|Anti-D||Yes||Yes||15||When a D variant person makes partial anti-D, the antibody is of the same clinical significance as when a D negative person makes complete anti-D.|
|Anti-E||Yes||Yes||70||Naturally occurring anti–E appears not to cause transfusion reactions or in-vivo haemolysis.|
|Anti-K||Yes||Yes||91||Kx is the precursor antigen for the Kell system antigens and Kx negative cells are known as the McLeod phenotype which is associated with X linked Chronic Granulomatous Disease.|
|Anti-k||Yes||Yes||<0.1||Some fatal hydropic instances of HDN due to maternal anti-k are known|
|Anti-M||No||No||22||Anti-M is often unable to fix complement and has a thermal range of activity below 37oC and is considered to be of no clinical significance in that instance. Anti-M is far more common in children than adults.|
|Anti-N||No||No||28||Most examples are naturally occurring.|
|Anti-U||Yes||Yes||<0.001||U- cells need to be ordered from the frozen bank in Liverpool. Patients with anti-U are also S-s- and can form both these antibodies. Known U- people are encouraged to donate.|
|Anti-P1||No||Rare||22||The P1 antigen is described in many instances throughout nature.|
|Anti-Lea||Rare||No||77||Frequently naturally occurring. Can be stimulated by pregnancy and disappears postnatally.|
|Anti-Jka||Yes||Yes||23||These may not be detectable in subsequent samples but the antibody may still cause haemolytic transfusion reactions - accurate transfusion records are essential in these patients. Involved in urea membrane transport.|
|Anti-Fya||Yes||Yes||35||Fy(a-b-) red cells are resistant to invasion by the malarial parasites Plasmodium vivax and knowlesi.|
|HTLA Ab's||No||No||Low||Antibodies of the HTLA type include:- Knops (Kna/Knb), McCoy (McCa), York (Yka), Chido (Cha), Rogers (Rga), Cost (Csa/Csb) and JMH (John Milton Hagen).|