OBJECTIVES: To evaluate whether risk scores used to classify patients with primary myelofibrosis and JAK-2 V617F mutation status can predict clinical outcome. METHODS: A review of clinical and laboratory data from 74 patients with primary myelofibrosis diagnosed between 1992 and 2011. The IPSS and Lille scores were calculated for risk stratification and correlated with overall survival. RESULTS: A V617F JAK2 mutation was detected in 32 cases (47%), with no significant correlation with overall survival. The patients were classified according to the scores: Lille - low, 53 (73.%); intermediate, 13 (18%); and high, 5 (7%); and IPSS- low, 15 (26%); intermediate-1, 23 (32%); intermediate-2, 19 (26%); and high, 15 (31%). Those patients presenting a higher risk according to the IPSS (high and intermediate-2) had a significantly shorter overall survival relative to the low risk groups (intermediate-1 and low) (p = 0.02). CONCLUSIONS: These results emphasize the importance of the IPSS prognostic score for risk assessment in predicting the clinical outcome of primary myelofibrosis patients.

The influence of different Trypanosoma cruzi biodemes on the evolution of the infection and on the histopathological lesions of the heart and skeletal muscles, during the experimental infection of Calomys callosus, was investigated. Three groups of C. callosus were infected, respectively, with parasite strains representative of three different Biodemes: Type I (Y strain), Type II (21 SF strain), and Type III (Colombian strain). For each group, normal C. callosus were also used as controls. Marked differences have been detected in the responses of C. callosus to the infection with the three strains in this model. The strains Types I and II (Y and 21 SF) determined moderate lesions, mostly in the myocardium, with low parasitism, a rapid course, and total regression of the lesions by the 60th day of infection. Differently, Type III strain (Colombian), was more pathogenic for C. callosus and induced necrotic-inflammatory lesions in skeletal muscles and myocardium, in correspondence to intracellular parasitism. Proliferation of fibroblasts and amorphous matrix deposits, followed by interstitial fibrosis were present. Progressive regression of the inflammatory changes and collagen deposits occurred spontaneously. The progression and regression of both inflammation and fibrosis induced by the Colombian strain were further submitted to quantitative evaluation by morphometry. Results of the morphometric studies presented good correlation with the histopathological findings. The results confirm the importance of the different biodemes in the determination of tissue lesions and the peculiarities of response of C. callosus to infection with T. cruzi.