MNS Blood Group System

• MNS Blood Group System has an ISBT no. 002 with symbol MNS
• MNS Antigen has 2 linked genes on chromosome 4 are responsible for this blood group
• GYPA produces glycophorin A (GPA) on the cell membrane
• GPA structure carries the M and N antigens
• GYPB produces glycophorin B (GBP) on the cell membrane
• GPB structure carries the S and s antigens
• M antigen demonstrate serine and glycine at the 1st and 5th position, respectively
• N antigen demonstrate leucine and glutamic acid
• M and N antigens destroyed by enzyme treatment with ficin, papain, bromelin, trypsin, and pronase and destroyed by ZZAP (combination of DTT and papain or ficin)
• M and N antigens are Not affected by DTT alone, 2-aminoethyliso-thiouronium bromide (AET), α-chymotrypsin, chloroquine, or glycine-acid EDTA treatment
• S antigen demonstrated methionine at the 29th position; s antigen demonstrates threonine at this position
• S and s antigens may be destroyed when RBCs are treated with ficin, papain, bromelin, pronase and α-chymotrypsin
• Trypsin dose not destroy the S and s antigens, and neither does DTT, AET, chloroquine, or glycine-acid EDTA treatment
• U antigens are resistant to enzyme treatment
• RBCs with S or s antigens also have U antigen
• MNS antigen can serve as a receptors for complement, bacteria, and viruses.
• GPA may serve as the receptor by which certain pyelonephritogenic strains of Escherichia coli gain entry to the urinary tract.
• Plasmodium falciparum appears to use alternative receptors, including GPA and GPB, for cell invasion
• Anti-M is usually naturally-occurring and may be both IgM and IgG
• Anti-M does not bind complement and does not react with enzyme treated RBCs
• Anti-M reacts optimally at room temperature and rarely associated with HDN and HTR
• Anti-N are rarely encountered
• Anti-N is weak, naturally-occurring IgM antibodies and reacts best at room temperature or below
• Anti-N does not bind complement or react with enzyme treated RBCs and not usually associated with HDN and HTR
• Anti-N is seen in patients who were dialyzed on equipment sterilized with formaldehyde
• Dialysis-associated anti-N reacts with any N+ or N- RBCs treated with formaldehyde and is called anti-Nᶠ
• Anti-S, anti-s, and anti-U antibodies have rare IgG antibodies that usually develop following RBC stimulation
• Anti-S, anti-s and anti-U antibodies are usually reactive in the antiglobulin phase of testing but some saline reactive antibodies have been reported
• Anti-S, anti-s, and anti-U may bind complement and have been associated with severe HDN and HTR
• Many M, N, and S antibodies demonstrate a dosage effect; that is, they react more strongly with homozygous than heterozygous cells
• Vicia graminia, Bauhinia variegate, Bauhinia purpura for Anti-N
• Iberis amara for Anti-M
• Human, rabbit, and monoclonal serum-typing reagents