2)Complement detects self vs nonself cells by these complement inhibitors. Function of these complement inhibitors is to:
3)In the absence of these inhibitors, complement proteins bind cell membranes of our own cells and through the alternative complement pathway can lyse self-cells.
4)CD55/DAF decrease → More C3 convertase→Increase C3b→Increase opsonization→Extra Vascular Hemolysis.
CD59/MIRL decrease→More MAC→Intra Vascular Hemolysis.
5)Why nocturnal hemoglobinuria- hemolysis occurs throughout day but its more at night because: (a)Increased hemolysis in night due to respiratory acidosis(Shallow breathing).
(b)Overnight concentration of urine is more and hemoglobinuria is clearly evident.
6)Diagnosis:(a)Flow cytometry- decrease CD55 and CD59 levels.
(b)HAM test-confirmatory.
(c)Direct coombs test-Negative (Helps to differentiate PNH and AIHA- its positive in AIHA)
7)Treatment:
-Srikar Sama
SOURCE: UpToDate, Uworld.