Anti-i antibodies

[gagpinks]

If a child is found to have anti-i by what mechanism can it cause complement activation bearing in mind all adult cells Are i negative. Does it bind non specifically to the patients red cells? 

Edited February 16, 2017 by gagpinks

[Malcolm Needs ☆]

14 minutes ago, gagpinks said:

If a child is found to have anti-i by what mechanism can it cause complement activation bearing in mind all adult cells Are i negative. Does it bind non specifically to the patients red cells? 

Not all adult red cells are i negative (and I am not talking about the rare adult ii phenotype).  Although adult red cells express large amounts of I, they also express small amounts of i.  This is why all antibodies that have anti-i specificity are auto-antibodies, rather than alloantibodies.

Anti-i, like anti-I, is almost always IgM, and so both will readily activate complement, but it is not non-specific.