From the Research
Yes, PNH (Paroxysmal Nocturnal Hemoglobinuria) can cause bone marrow aplasia without evidence of hemolysis, as it is a clonal disorder affecting hematopoietic stem cells, which can impair normal blood cell production independently of the hemolytic process 1.
Key Points to Consider
- PNH can present as a hemolytic anemia, a form of bone marrow failure, a thrombophilia, or any combination of the above 1.
- The absence of hemolysis doesn't rule out PNH, and patients with bone marrow failure should still be evaluated for PNH even if they don't exhibit classic hemolytic symptoms.
- Diagnosis in such cases would rely on flow cytometry to detect PNH clones rather than markers of active hemolysis.
- Terminal complement inhibition is highly effective for treating intravascular hemolysis from PNH and virtually eliminates the risk of thrombosis, but is not effective for treating bone marrow failure 1.
Implications for Clinical Practice
- Patients with bone marrow failure should be evaluated for PNH, even in the absence of hemolysis.
- Flow cytometry is a sensitive and quantitative method for detecting PNH clones, and can be used to diagnose PNH in patients with bone marrow failure 2, 3.
- The presence of PNH clones in patients with myelodysplastic syndromes and related bone marrow diseases has prognostic and therapeutic implications 3.
- Anticoagulant treatment is recommended after a thromboembolic event, but has no place in primary prophylaxis 4.
Recent Findings
- A recent study found that PNH clones can disappear in patients with myelodysplastic syndrome, highlighting the complex link between MDS and PNH 5.
- The distinction between MDS and PNH may be difficult in some cases, and the clinical phenotype may be the leading feature for treatment decisions in the era of complement inhibition 5.