Paroxysmal Nocturnal Hemoglobinuria
Published: December 2010
Hot Topic Q&A is an opportunity for viewers to submit questions to the Hot Topic presenter. The opportunity to submit questions for this topic is now closed.
The following questions were submitted by viewers and answered by the presenter, Dragan Jevremovic, MD, PhD, Co-Director of the Cell Kinetics Laboratory in the Division of Hematopathology. Questions are presented as submitted (unedited).
What is the flow protocol used (exact gating for the different types of cells) and how do you differentiate between types 1 and 2 PNH + RBC?
For granulocytes: gating on live cells, nonaggregates, forward and side scatter, side scatter/CD45, CD15-positive cells. Then look for the loss of CD16, CD24 and fluorescent-labeled inactive toxin aerolysin (FLAER).
For monocytes: gating on live cells, non-aggregates, forward and side scatter, side scatter/CD45, CD33-positive cells. Then look for the loss of CD14 and FLAER.
For red blood cells (RBCs): gating on live cells, nonaggregates, forward and side scatter, glycophorin-A-positive cells. Then look for the loss of CD59. The gating for partial loss (type II) requires recognition of separate peaks on the CD59 histogram display.
The stated median age for acquiring disease is 30. Do those who have this disease start off with a small amount of hemoglobin in their urine and progress to more hemoglobin as time goes on?
Yes, however the rate of progression can vary and is related to the size of the PNH clone. In fact, only a minority of patients with PNH will have classic bouts of red/brown urine; the majority has no noticeable or only intermittent episodes, not related to the time of the day. Patients with hemoglobinuria are more likely to have a large PNH clone and hypercellular bone marrow, as they are still actively producing PNH clone.