Question | Answer |
HTLA characteristics | -IgG usually non C binder -against high incidence antigens - seen in multiply transfused patients - hides alloantibodies - reacts weakly w/cord cells |
Chido/Rodgers system | Antigens water soluble; adsorbed onto RBC from plasma--part of C4d on chrome 6-- Ag not well developed at birth--98% white are Cha+ |
Are Ch & Rg antigens destroyed by enzymes? | Yes |
Is it necessary to give Ch/Rg antigen negative blood?? | No, because the Ab will be neutralized by plasma prior to transfusion |
Procedures to ID Ch/Rg antigens (4) | 1) Ag neg cells reacted w/plasma 2)enzyme treatment 3)reaction of plasma w/C4d coated RBCs 4)Neutralization w/plasma from Ch/Rg positive person |
Plasma inhibition (neutralization) for Ch/Rg | -Pooled plasma from 6 pts |
What is the control of plasma inhibition? | Albumin |
Sid (Sda) Antigen | 91% of pop has...variable expression...cord cells lack |
Sda antibody | ALWAYS gives MF reaction (refractile).....Neutralizable with urine from Sda+ person |
Do you need to give Sda negative units? | No |
Bg antigens | Class I HLA, strongly expressed on WBCs & PLTs, IgG cline sig, appears as Ab to low freq Ag |
Are Bg antigens enzyme destroyed? | No, but chloroquine will remove |
Most important platelet antigens (5) | 1) GPIa, GPIb, GPIIb, GpIIIa, CD109 |
PLT Ag that 98% of whites express? | HPA-Ia or PLa1-------part of GPIIIa glycoproteins |
PLT Ags are stimulated by random donor PLTs and can cause ______ & _____ | Post transfusion purpura & neonatal alloimmune thrombocytopenia |