Abstract: The clinical characteristics of the  pathogenesis of primary myelofibrosis (PMF) with paroxysmal nocturnal hemoglobinuria (PNH) were analyzed. Bone marrow imaging and bone marrow pathology were carried out  by means of cytochemical staining and silver staining. Flow cytometry(FCM) was used to detect CD55 and CD59 on the surface of erythrocytes and granulocytes. And the granulocytes and monocytes were detected by FLAER.For further diagnosis,  highthroughput sequencing technology(also known as the second generation sequencing)was used for genetic testing.The patient was clinically characterized by severe splenomegaly and anemia, which might be diagnosed with PMF by bone marrow examination.However, bone marrow pathology showed myelofibrosis (MF) grade 3. Genetic testing showed that BCR/ABL fusion gene was negative and JAK2 V617F positive. Therefore, the patient was diagnosed with PMF.Then, the patient was treated with danazol, testosterone undecanoate, erythropoietin(EPO),  thalidomide, and blood product  support.While the blood product infusion was ineffective during treatment and brown urine appeared,  but the relevant examination was improved.The blood routine test showed that high reticulocyte,  direct bilirubin,  indirect bilirubin were  high,  the Coombs test was  negative for twice, FCM showed the reduction of  CD55 and CD59,   and FLAER presented the expression defect of granulocytes and monocytes. And PIGA gene mutation was found positive.Therefore, the patient was diagnosed as PMF with PNH.

Key words: primary myelofibrosis；hemoglobinuria, , paroxysmal； pathogenesis, gene mutation