Emergence of IgG3 alloantibody after renal transplantation associated with early graft failure.

In this small study, emergence of complement-fixing alloantibody in the early post-operative period was associated with clinical antibody-mediated rejection that required treatment. It appears that IgG3 alloantibody may be a significant determinant of poorer allograft outcome and failure to respond to PE therapy. Intuitively, it is reasonable that IgG3 may escalate the damage to an allograft over IgG1 alone due to its higher affinity for complement fixation. However, the inability to remove IgG3 by PE filtration was unexpected and may promote refractory rejection. On the other hand, the conversion of alloantibody to IgG2 among the Rescued group may be pivotal to their successful reversal of rejection. The clinical consequences of these atypical isotype presentations upon long-term renal allograft survival are unknown and warrant further study.