A reference guide for paroxysmal nocturnal hemoglobinuria: recent updates and points of medical treatment

Abstract

Paroxysmal nocturnal hemoglobinuria (PNH) causes clonal expansion of hematopoietic stem cells with abnormal GPI-anchor biosynthesis. The major pathological condition of PNH is that the erythrocytes lacking the complement regulatory factors CD55 and CD59, which are GPI-anchored proteins, lead to intravascular hemolysis through complement activation. Clonal expansion has been assumed to be involved in an immunological attack on hematopoietic stem cells, and the bone marrow failure associated therewith modifies the pathology to varying degrees. The introduction of eculizumab made complement control possible; however, the problems associated with it became apparent as the treatment progressed. Additionally, the PNH Reference Guide was significantly revised in 2016, partly because PNH was designated as a Japanese medical subsidy. With the revised edition of 2020, minor revisions have been added to reflect further advances in treatment and understanding of the disease, while mainly dealing with the clinical introduction of eculizumab derivative, ravulizumab, which uses recycling antibody technology. This review outlines the points of the 2020 revision, including the important points of the previous revision.