Case report: persistent anemia after eculizumab in paroxysmal nocturnal hemoglobinuria: non-dominantly active intravascular hemolysis.
Baozhi Fang, Xiao Yu, Yifei Zhou et al.
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Case in brief
A patient with paroxysmal nocturnal hemoglobinuria initially responded to eculizumab but developed recurrent hemoglobin decline and transfusion dependence after 24 weeks. LDH did not rise significantly, and the anti-C3d direct antiglobulin test was only weakly positive. However, changes in free hemoglobin, haptoglobin, and type III red blood cells supported ongoing, subclinical intravascular hemolysis. After six weeks of iptacopan monotherapy, these laboratory markers normalized, transfusions were no longer needed, and type III red blood cells increased to 57.3%.
What made this case unusual
Persistent anemia and transfusion dependence occurred despite no significant LDH increase, making the residual intravascular hemolysis clinically subtle; other biomarkers and red-cell phenotype changes indicated ongoing activity.
Diagnostic / clinical pearl
In PNH with persistent anemia after C5 inhibition, a non-elevated LDH does not exclude active intravascular hemolysis; interpret it alongside free hemoglobin, haptoglobin, and red-cell phenotype.