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Welcome Back to Immunohematology. Other Antigen Systems Part II – Kell, Duffy, Kidd, MNSs. Kell System. COOH. NH 2. NH 2. COOH. Kx K. Kell System. Main antigens are K (Kell) and its allele, k (Cellano). Antigens are glycoproteins.
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Welcome Back to Immunohematology Other Antigen Systems Part II – Kell, Duffy, Kidd, MNSs
KellSystem COOH NH2 NH2 COOH Kx K
KellSystem • Main antigens are K (Kell) and its allele, k (Cellano). • Antigens are glycoproteins. • K is second only to D in its immunogenicity. • Antigens are not affected by routine enzymes.
Kell System Antibodies • Usually IgG • React best in the Coombs phase (AHG). • Do not show dosage. • Some anti-K antibodies activate complement. Other antibodies in the Kell system do not.
Dosage • An antibody that reacts stronger with a cell that has homozygous expression of an antigen than it does with a cell showing heterozygous antigen expression is said to show dosage.
Naturally occurring? HTR? HDFN? Clinically significant? No Yes Yes Yes Kell System
Duffy System Fya/Fyb NH2 COOH
Duffy System • The most common alleles are Fya and Fyb. • Antigens are glycoproteins. • Antigen frequency varies among the races. • 65% of whites are Fya positive, while only 10% of blacks are Fya positive. • The most common phenotype in blacks is Fy(a-b-) at 68%. This phenotype in whites is extremely rare. • Destroyed by enzymes.
Duffy System Antibodies • Are IgG. • React best at the AHG phase. • Show dosage. • Some Duffy antibodies activate complement.
Naturally occurring? HTR? HDFN? Clinically significant? No Yes Yes Yes Duffy System
Kidd System Jka/Jkb NH2 COOH
Kidd System • The major alleles of the Kidd system are Jka and Jkb. • Antigens are glycoproteins. • Antigen frequency varies among races. • Jk(a-b-) phenotype extremely rare. • Not very immunogenic. • Enhanced by enzymes.
Kidd System Antibodies • Usually IgG. • Best detected at the AHG phase. • Show dosage. • Noted for ability to activate complement. • Notorious for causing delayed hemolytic transfusion reactions.
Naturally occurring? HTR? HDFN? Clinically significant? No Yes Yes Yes Kidd System
MNSs System MN NH2 NH2 Ss COOH COOH Glycophorin A Glycophorin B
MNSs System • The major antigens of this system are: • M and its allele N • S and its allele s • The most common phenotypes are: • M+N+ • S-s+ • Antigens can be destroyed by enzymes.
MNSs System Antibodies • Anti-M and -N are usually IgM antibodies. • Many examples of IgG anti-M’s. • Anti-M may react over a wide temperature range (wide thermal amplitude). • Anti-N reacts best in saline (immediate spin). • Anti-S and -s are IgG antibodies. • React best at AHG. • Show dosage. • May activate complement.
Naturally occurring? M & N yes S & s usually immune HTR? S & s yes sometimes M, N usually not HDFN? S & s yes M & N no Clinically significant? M & N usually not S & s yes MNSs System