Paroxysmal nocturnal hemoglobinuria (PNH) is a complex, acquired blood disorder characterized by hemolytic anemia, bone marrow failure, and a predisposition to thrombosis. While these clinical features are indicative, a definitive Pnh Diagnosis requires sophisticated laboratory investigations, primarily flow cytometry, to characterize the deficiency of glycosyl phosphatidylinositol (GPI)-anchored proteins on blood cells. Accurate diagnosis is paramount for effective management and to understand the contributions of hemolysis and marrow failure to the patient’s condition. This article will delve into the essential aspects of PNH diagnosis, expanding on current knowledge and providing a robust, SEO-optimized resource for those seeking in-depth information.
Definition and Diagnostic Criteria
Definition
PNH arises from the clonal expansion of hematopoietic stem cells harboring a somatic mutation in the PIGA gene. This mutation leads to a deficiency in GPI-anchored proteins (GPI-APs) on the surface of blood cells. Crucially, the lack of GPI-linked complement regulatory proteins, CD55 and CD59, renders red blood cells susceptible to complement-mediated destruction, resulting in intravascular hemolysis, the hallmark of classic PNH. It is important to note that PNH frequently co-occurs with bone marrow failure syndromes, most notably aplastic anemia, and thrombophilia represents a significant cause of morbidity and mortality.
Classification
To better understand the variable clinical presentations and disease courses of PNH, a classification system has been developed, categorizing PNH into three main subtypes (Table 1). This classification is a dynamic framework, subject to refinement as research progresses, but currently serves as a valuable tool for standardized communication and clinical management.
Table 1. Classification of PNH
| Category | Description
