Paroxysmal nocturnal haemoglobinuria ( PNH) is a clonal hematopoietic stem cell disease characterized by intravascular hemolytic anemia , pancytopenia and thrombosis .Although PNH is an non-malignant disease , its complications have very negative impacts on patient's quality of life .The most common serious complication is thrombosis formation .

A 57-year-old man was admitted to hospital with diarrhea for 10 months and dizziness for 4 months. The patient had 1-2 liters watery stool per day, without pyogenic blood or abnormality in gastroenteroscopy examination. The level of hemoglobin and albumin was generally normal, and fasting test was positive. At the same time, he was accompanied with hyperalgesia of lower limbs and orthostatic hypotension. After the discussion of multiple disciplinary teams, the patient was diagnosed with amyloidosis by sural nerve biopsy, myocardial MRI, and the assays of urine immunoelectrophoresis and serum free light chain. Light chain amyloidosis was confirmed after excluded the diagnosis of familial amyloidosis. The patient was improved after courses of chemotherapy with melphalan and dexamethasone.

OBJECTIVETo explore the high risk factors of thrombosis in paroxysmal nocturnal hemoglobinuria (PNH). It has been reported that in Chinese patients with venous thrombosis, the mutation frequency in PROC c.574_576 del (rs199469469), PROC c.565C>T (rs146922325) and THBD c.-151G>T (rs1698852) was higher than that of normal controls, indicating its importance in thrombophilia pathogenesis.

METHODS142 patients with PNH diagnosed between 2009 and 2015 were enrolled in the study. Clinical data were analyzed and thrombophilia risk factors, such as the level of protein C, protein S, antithrombin III, APC resistance, blood fat, phospholipid antibody, were evaluated. Samples from patients and 100 normal controls were detected for the mutations of PROC c.574_576 del (rs199469469), PROC c.565C>T (rs146922325) and THBD c.-151G>T (rs1698852) by Sanger sequence.

RESULTSOf the 142 PNH patients, 21 (14.8%) patients had at least 1 episode of thrombotic event. Only 2 patients had arterial thrombosis and 19 patients had venous thrombosis. The median age of patients with thrombosis was 35 years old, similar to those without episode (40 years old, P=0.687). The ratios of males and females were 1.33 in thrombosis group and 1.57 in non-thrombosis group (P=0.728) , respectively. Patients with thrombosis had the same disease pattern compared with those without episode. Although there was no difference in the level of hemoglobin, WBC and PLT count, and LDH level between patients with thrombosis and those without episode, patients with thrombosis showed higher RBC, higher percentage of CD59(-) granulocytes and RBC, and Flaer(-) granulocytes compared with those without episode. The routine thrombophilia screening tests did not show any difference either between PNH patients and normal controls, or between patients with or without thrombosis. There were two mutations in rs199469469 and rs16984852 sites in patients with PNH, but the mutated patients did not have any thrombosis. Mutation rs146922325 was found in PNH patients. The mutation rate was similar between PNH patients and normal controls, thrombotic PNH and non-thrombotic PNH (P>0.05).

CONCLUSIONSCompared with non-thrombotic patients, PNH thrombotic patients have bigger PNH clone and higher RBC count. There are no differences among the routine thrombophilia factors and the three known venous eligible genes either between PNH patients and normal controls or between thrombotic and non-thrombotic PNH patients.

Adult ; Antithrombin III ; metabolism ; Case-Control Studies ; Clone Cells ; cytology ; Female ; Granulocytes ; cytology ; Hemoglobinuria, Paroxysmal ; genetics ; physiopathology ; Humans ; Leukocyte Count ; Male ; Protein C ; metabolism ; Protein S ; metabolism ; Risk Factors ; Thrombosis ; genetics ; physiopathology

Objective: To improve the understanding of the rare clinical presentation and management of purpura fulminans (PF) in patients with paroxysmal nocturnal haemoglobinuria (PNH). Methods: A case of PF occurring in PNH is reported, while the related literature review is conducted. Results: A 49-year-old male patient suffered from one-week history of fever, greenish-brown colour urine, multiple well demarcated and painful purpura of the head and neck. He had been reported to have two thromboembolic events during the 22-year course of PNH. Skin biopsy displayed classic PF features. Laboratory testing showed a high PNH clone, intravascular hemolysis and coagulation system changes. After sufficient anticoagulation and short course of glucocorticoid therapy, the clinical conditions were improved correspondingly. During a follow-up period of 6 month, there was no recurrence of thrombosis. Conclusion PF should be considered in PNH patients with unexplained, quickly developed painful purpura. Extensive work-up should be performed to find out other potential thrombophilic risk factors after diagnosis of PF. Early diagnosis, adequate anticoagulation therapy and control hemolysis were essential to PF treatment occurring in PNH. The survival of patients and the qualities of life can be improved. The PNH clone detection is needed to evaluate the status of procoagulation and predict the risk of recurrent thrombosis.

Objective: To understand the effect of sirolimus on the erythropoiesis of K562 cell line and bone marrow cells from pure red cell aplasia (PRCA) patients and normal controls. Methods: Different concentrations (10, 100, 1 000 nmol/L) of sirolimus were added to the K562 cell line or bone marrow cells from PRCA patients or normal controls and cultured 14 days for BFU-E formation. Meanwhile, sirolimus was also added to the serum treated PRCA bone marrow cells to cultivate for the same priod of time. Results: Neither K562 cells, bone marrow cells from PRCA patients or normal controls showed any difference when sirolimus was added to the culture system for BFU-E. However, BFU-E formation decreased after serum was added in PRCA patients (76.40±22.48 vs 136.33±12.58, t=-4.329, P=0.001) and this suppression of BFU-E was partly corrected by 1 000 nmol/L sirolimus treatment (97.14±15.83 vs 76.40±22.48, P=0.038). Conclusions Sirolimus may modulate the suppression of erythropoiesis by serum instead of directly stimulate the growth of red blood cells in PRCA patients.