Idiopathic refractory ascites after allogeneic stem cell transplantation: a previously unrecognized entity.

At our center, we observed a series of patients who developed transudative refractory ascites secondary to noncirrhotic, non-veno-occlusive disease (VOD)-related portal hypertension after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Patients were considered to have idiopathic portal hypertension-related refractory ascites (IRA) if they developed ascites secondary to intrahepatic portal hypertension (serum ascites albumin gradient ≥1.1 g/dL or hepatic venous pressure gradient [HVPG] >5 mm Hg), but did not meet the clinical criteria for classical VOD/sinusoidal obstructive syndrome (SOS) and did not have any alternate etiology of portal hypertension. From our institutional database, we identified 40 patients who developed IRA after allo-HSCT between 2004 and 2018. The patients' median age at the time of allo-HSCT was 54 years (range, 21-73 years). The median time to development of IRA after allo-HSCT was 80 days (range, 16-576 days). The median number of paracentesis was 3 (range, 1-11), and 15 (38%) patients had an intraperitoneal catheter placed for continued drainage of the rapidly accumulating ascites. Portal pressures were measured in 19 patients; 6 (15%) had moderate portal hypertension (HVPG 6-9 mm Hg), and 13 (33%) had severe portal hypertension (HVPG ≥ 10 mm Hg). Liver biopsy was performed in 24 patients. None of the patients met the criteria for classical VOD/SOS (clinical/histological) or cirrhosis (histological). The cumulative incidence of nonrelapse mortality was 63%, and the median survival duration after the development of the IRA was 7 months (range, 0.8-125.6 months). IRA is a poorly understood and often fatal complication of allo-HSCT.

A distinct molecular mutational profile and its clinical impact in essential thrombocythemia and primary myelofibrosis patients.

BACKGROUND: Classical MPNs including ET and PMF have a chronic course and potential for leukaemic transformation. Timely diagnosis is obligatory to ensure appropriate management and positive outcomes. The aim of this study was to determine the mutational profile, clinical characteristics and outcome of ET and PMF patients in Pakistani population. METHODS: This was a prospective observational study conducted between 2012 and 2017 at NIBD. Patients were diagnosed and risk stratified according to international recommendations. Response to treatment was assessed by IWG criteria. RESULTS: Of the total 137 patients analysed, 75 were ET and 62 were PMF. JAK2 positivity was seen in 51 cases (37.2%), CALR in 41 cases (29.9%), while triple-negative in 17 (12.4%) cases. None of the patients in the present study were MPL positive. Overall survival for patients with ET and PMF was 92.5 and 86.0% respectively and leukaemia free survival was 100 and 91.6% respectively, at a median follow-up of 12 months. Leukaemic transformation occurred in 6.5% of MF patients; among them, JAK2 mutation was frequently found. Molecular mutations did not influence the OS in ET whereas in PMF, OS was shortest in the triple-negative PMF group as compared to the JAK2 and CALR positive patient groups. CONCLUSION: This study shows a different spectrum of molecular mutations in ET and PMF patients in Pakistani population as compared to other Asian countries. Similarly, the risk of leukaemic transformation in ET and PMF is relatively lower in our population of patients. The factors responsible for these phenotypic and genotypic differences need to be analysed in large scale studies with longer follow-up of patients.

Coexisting JAK2V617F and CALR Exon 9 Mutation in Essential Thrombocythemia.

Classic "BCR-ABL1-negative" MPN is an operational sub-category of MPN that includes polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) harboring JAK2V617F as the most common mutation. JAK2V617F can be detected in about 95 % of patients with PV while remaining 5 % of PV patients carry a somatic mutation of JAK2 exon 12. Approximately one-third of patients with ET or PMF do not carry any mutation in JAK2 or MPL. In December 2013, mutations were described in calreticulin (CALR) gene in 67-71 and 56-88 % of JAK2V617F and MPL negative patients with ET and PMF, respectively. Since this discovery CALR mutations have been reported to be mutually exclusive with JAK2V617F or MPL mutations. However recently few studies (eleven published reports) reported the coexistence of JAK2V617F and CALR in MPN. In the present study we are reporting JAK2V617F positive ET patient from our center with coexisting CALR exon 9 mutation type c.1214_1225del12 (p.E405_D408del) that was never reported before as a coexisting mutation and describing in detail the clinical outcomes.

Coexisting JAK2V617F and CALR Exon 9 Mutations in Myeloproliferative Neoplasms - Do They Designate a New Subtype?

The classic BCR-ABL1-negative myeloproliferative neoplasm is an operational sub-category of MPNs that includes polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). The JAK2V617F mutation is found in ~ 95% of PV and 50-60% of ET or PMF. In most of the remaining JAK2V617F- negative PV cases, JAK2 exon 12 mutations are present. Amongst the JAK2V617F-negative ET or PMF 5-10% of patients carry mutations in the MPL gene. Prior to 2013, there was no specific molecular marker described in the remaining 30-40% ET and PMF. In December 2013, two research groups independently reported mutations in the gene CALR found specifically in ET (67-71%) and PMF (56-88%) but not in PV. Initially CALR mutations were reported mutually exclusive with JAK2 or MPL. However, co-occurrence of CALR mutations with JAK2V617F has been reported recently in a few MPN cases. Many studies have reported important diagnostic and prognostic significance of CALR mutations in ET and PMF patients and CALR mutation screening has been proposed to be incorporated into WHO diagnostic criteria for MPN. It is suggestive in diagnostic workup of MPN that CALR mutations should not be studied in MPN patients who carry JAK2 or MPL mutations. However JAK2V617F and CALR positive patients might have a different phenotype and clinical course, distinct from the JAK2-positive or CALR-positive subgroups and identification of the true frequency of these patients may be an important factor for defining the prognosis, risk factors and outcomes for MPN patients.