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. 2016 Feb 23;5:F1000 Faculty Rev-209. [Version 1] doi: 10.12688/f1000research.7288.1

Figure 3. The dual pathogenesis of paroxysmal nocturnal hemoglobinuria (PNH).

Figure 3.

The diagram shows, on the right-hand side, the presumed pathogenesis of aplastic anemia (AA): a T-cell-mediated autoimmune attack damages hematopoietic stem cells (HSCs). The target of the auto-reactive T cells may be the glycosylphosphatidylinositol (GPI) molecule or another molecule expressed on HSCs. On the left-hand side, an inactivating mutation of the PIG-A gene in a HSC produces a GPI-negative hematopoietic clone. In the absence of the PIG-A mutant clone, the autoimmune attack, even if GPI is targeted, produces AA. In the absence of the autoimmune attack, a PIG-A mutant clone will be of no consequence (subclinical). Only if both a PIG-A mutant clone and a GPI-targeted autoimmune attack co-exist will the mutant clone expand and cause clinical PNH.