Michele Merli

A prospective study of 338 patients with polycythemia vera: the impact of JAK2 (V617F) allele burden and leukocytosis on fibrotic or leukemic disease transformation and vascular complications

We studied the relationship between JAK2 (V617F) mutant allele burden and clinical phenotype, disease progression and survival in patients with polycythemia vera (PV). The percentage of granulocyte mutant alleles was evaluated using a quantitative real-time polymerase chain reaction-based allelic discrimination assay. Of the 338 patients enrolled in this prospective study, 320 (94.7%) carried the JAK2 (V617F) mutation. Direct relationships were found between mutant allele burden and hemoglobin concentration (P=0.001), white blood cell count (P=0.001), spleen size (P=0.001) and age-adjusted bone marrow cellularity (P=0.002), while an inverse relationship was found with platelet count (P<0.001). During the study period, eight patients progressed to post-PV myelofibrosis (MF) (all carrying >50% mutant alleles), while 10 patients developed acute myeloid leukemia (AML). The mutant allele burden was significantly related to the risk of developing myelofibrosis (P=0.029) and retained its significant effect also in multivariable analysis (P=0.03). By contrast, the risk of developing AML as well as that of thrombosis was not significantly related to mutant allele burden. Leukocytosis did not affect thrombosis, MF, leukemia or survival. In conclusion, a JAK2 (V617F) allele burden >50% represents a risk factor for progression to MF in PV.

The BRAF V600E mutation in hairy cell leukemia and other mature B-cell neoplasms

The somatically acquired V600E mutation of the BRAF gene has been recently described as a molecular marker of hairy cell leukemia (HCL). We developed an allele-specific PCR for this mutation and studied 62 patients with HCL, 1 with HCL variant, 91 with splenic marginal zone lymphoma, 29 with Waldenström macroglobulinemia, and 57 with B-cell chronic lymphoproliferative disorders. The BRAF V600E mutation was detected in all HCL cases and in only 2 of the remaining 178 patients. These 2 subjects had B-cell chronic lymphoproliferative disorders that did not fulfill the diagnostic criteria for HCL. Despite the positive PCR finding, the mutation could not be detected by Sanger sequencing in these 2 cases, suggesting that it was associated with a small subclone. We conclude that the BRAF V600E mutation is present in all patients with HCL and that, in combination with clinical and morphologic features, represents a reliable molecular marker for this condition.

Bone marrow histology in marginal zone B-cell lymphomas: correlation with clinical parameters and flow cytometry in 120 patients

BACKGROUND Among marginal zone lymphomas (MZLs), bone marrow (BM) involvement features are well established in the splenic marginal zone lymphoma (SMZL); few data are available for extranodal marginal zone lymphoma (EMZL) and nodal marginal zone lymphoma (NMZL). PATIENTS AND METHODS Incidence and patterns of histologic BM involvement are studied in 120 MZL patients (48 SMZL, 59 EMZL, 13 NMZL) at onset and during follow-up; relationships between clinical features, BM histology and flow cytometry (FC) are analyzed. RESULTS At diagnosis, BM involvement occurs in 90% SMZL, 22% EMZL and 54% NMZL (P<0.0001); at reevaluation, incidence raises to 96% in SMZL and 34% in EMZL. Concordance between histology and FC is found in 87% of cases; most discordant cases have positive histology but negative FC. SMZL and EMZL show a nodular BM infiltration; the interstitial pattern is frequent in NMZL (P<0.0001); sinusoidal localization is typical of SMZL, frequent in NMZL and occasional in EMZL (P=0.0001). Stage, leukemic disease, B symptoms, more than one extranodal involved site, splenomegaly, elevated beta2-microglobulin, serum monoclonal component, International Prognostic Index (IPI) and age-adjusted IPI are directly related to BM infiltration. CONCLUSIONS The different prevalence of BM involvement in MZL subtypes reflects their heterogeneous dissemination modalities; histology seems more sensible than FC to detect BM infiltration; development of BM involvement during follow-up is typical of EMZL.

Impact of treatment-related liver toxicity on the outcome of HCV-positive non-Hodgkin's lymphomas.

We studied 160 Hepatitis C virus (HCV)‐positive patients with NHL (59 indolent NHL, 101 aggressive). Median age was 67 years. HCV‐RNA was present in 146. HBsAg was positive in seven patients. At diagnosis, ALT value was above UNL in 67 patients. One hundred and twenty patients received an anthracycline‐based therapy, alkylators, 28 received chemotherapy plus rituximab. Cytotoxic drugs dose was reduced in 63 patients. Among 93 patients with normal ALT at presentation, 16 patients developed WHO grade II–III liver toxicity. Among 67 patients with abnormal ALT, eight patients had a 3.5 times elevation during treatment. Among 28 patients treated with rituximab and chemotherapy, five patients (18%) developed liver toxicity. Thirty four patients (21%) did not complete treatment (eight for liver toxicity). Median progression‐free survival (PFS) for patients who experienced liver toxicity is significantly shorter than median PFS of patients without toxicity (respectively, 2 years and 3.7 years, P = 0.03). After a median F‐UP of 2 years, 32 patients died (three for hepatic failure). A significant proportion of patients with HCV+ NHL develop liver toxicity often leading to interruption of treatment. This could be a limit to the application of immunochemotherapy programs. HCV+ lymphomas represent a distinct clinical subset of NHL that deserves specific clinical approach to limit liver toxicity and ameliorate survival. Am. J. Hematol., 2010.

Red blood cell transfusion-dependency implies a poor survival in primary myelofibrosis irrespective of IPSS and DIPSS

Risk stratification in primary myelofibrosis is currently based on two international prognostic scoring systems, neither of which takes into consideration red blood cell transfusion-dependency. In 288 consecutive patients with primary myelofibrosis, red blood cell transfusion-dependency at diagnosis affects survival independently of the International Prognostic Scoring System (P<0.001). To evaluate the dynamic impact on survival of red blood cell transfusion-dependency, we performed a Cox’s regression analysis with transfusion status as time-dependent covariate in 220 regularly followed patients with primary myelofibrosis. Patients who begin red blood cell transfusions anytime (n=80, 36%) have a significantly worse survival compared to those who continue follow up without transfusions (HR: 7.8, 95%CI: 5.1–11.9; P<0.001). Adjusting for Dynamic International Prognostic Scoring System in a multivariate analysis, red blood cell transfusion-dependency retained an independent prognostic impact on survival. This study suggests that red blood cell transfusion-dependency should be considered to improve risk stratification of primary myelofibrosis during follow up.

Indolent B-Cell lymphomas associated with HCV infection: Clinical and virological features and role of antiviral therapy

The association between hepatitis C virus (HCV) infection and B-cell non-Hodgkins lymphomas (NHL) has been demonstrated by epidemiological studies, in particular in highly endemic geographical areas such as Italy, Japan, and southern parts of United States. In these countries, together with diffuse large B-cell lymphomas, marginal zone lymphomas are the histotypes most frequently associated with HCV infection; in Italy around 20–30% cases of marginal zone lymphomas are HCV positive. Recently, antiviral treatment with interferon with or without ribavirin has been proved to be effective in the treatment of HCV-positive patients affected by indolent lymphoma, prevalently of marginal zone origin. An increasing number of experiences confirmed the validity of this approach in marginal zone lymphomas and in other indolent NHL subtypes like lymphoplasmacytic lymphoma. Across different studies, overall response rate was approximately 75%. Hematological responses resulted significantly associated with the eradication of the virus. This is the strongest evidence of a causative link between HCV and lymphomas. The aim of this paper is to illustrate the relationship between HCV infection and different subtypes of indolent B-cell lymphomas and to systematically summarize the data from the therapeutic studies that reported the use of antiviral treatment as hematological therapy in patients with HCV-associated indolent lymphomas.

Immunochemotherapy with in vivo purging and autotransplant induces long clinical and molecular remission in advanced relapsed and refractory follicular lymphoma

BACKGROUND To evaluate the clinical outcome of patients with relapsed or refractory follicular lymphoma treated with immunochemotherapy, in vivo purging and high-dose therapy with autotransplant. PATIENTS AND METHODS Sixty-four patients were enrolled in the trial. Primary end point was progression-free survival (PFS). Secondary end points were the in vivo purging effect on stem-cell harvest and the impact of molecular response on the outcome. RESULTS At enrollment, 59% of patients were PCR+ for bcl-2 rearrangement in bone marrow (PCR-informative). After the immunochemotherapy, before mobilization, 97% obtained complete response or partial response and 87% of patients informative for bcl-2 were molecularly negative. Sixty-one patients proceeded to in vivo purging and peripheral blood stem cell (PBSC) mobilization with rituximab and high-dose AraC. The median number of CD34+ cells collected was 16.6 x 10(6)/kg. Of 33 PCR-informative patients, the harvests resulted in PCR- in all. Fifty-eight patients received high-dose therapy and autotransplant of in vivo purged PBSC. After a median follow-up of 3.5 years, 41 patients are in complete remission. Five-year PFS is 59%. CONCLUSION This study demonstrates that patients with advanced relapsed or refractory follicular lymphoma treated with immunochemotherapy, in vivo purging and autotransplant may obtain long-lasting PFS. In bcl-2-positive patients, in vivo purging allows the harvest of lymphoma-free PBSC. Absence of the bcl-2 rearrangement after autotransplant is associated with persistent clinical remission.

The NOTCH pathway is recurrently mutated in diffuse large B cell lymphoma associated with hepatitis C virus infection

Hepatitis C virus has been found to be associated with B-cell non-Hodgkin lymphomas, mostly marginal zone lymphomas and diffuse large B-cell lymphoma. Deregulation of signaling pathways involved in normal marginal zone development (NOTCH pathway, NF-κB, and BCR signaling) has been demonstrated in splenic marginal zone lymphoma. We studied mutations of NOTCH pathway signaling in 46 patients with hepatitis C virus-positive diffuse large B-cell lymphoma and in 64 patients with diffuse large B-cell lymphoma unrelated to HCV. NOTCH2 mutations were detected in 9 of 46 (20%) hepatitis C virus-positive patients, and NOTCH1 mutations in 2 of 46 (4%). By contrast, only one of 64 HCV-negative patients had a NOTCH1 or NOTCH2 mutation. The frequency of the NOTCH pathway lesions was significantly higher in hepatitis C virus-positive patients (P=0.002). The 5-year overall survival was 27% (95%CI: 5%–56%) for hepatitis C virus-positive diffuse large B-cell lymphoma patients carrying a NOTCH pathway mutation versus 62% (95%CI: 42%–77%) for those without these genetic lesions. By univariate analysis, age over 60 years, NOTCH2 mutation, and any mutation of the NOTCH pathway (NOTCH2, NOTCH1, SPEN) were associated with shorter overall survival. Mutation of the NOTCH pathway retained an independent significance (P=0.029). In conclusion, a subset of patients with hepatitis C virus-positive diffuse large B-cell lymphoma displays a molecular signature of splenic marginal zone and has a worse clinical outcome.

Outcome prediction of diffuse large B-cell lymphomas associated with hepatitis C virus infection: a study on behalf of the Fondazione Italiana Linfomi

A specific prognostication score for hepatitis C virus-positive diffuse large B-cell lymphomas is not available. For this purpose, the Fondazione Italiana Linfomi (FIL, Italian Lymphoma Foundation) carried out a multicenter retrospective study on a large consecutive series of patients with hepatitis C virus-associated diffuse large B-cell lymphoma to evaluate the prognostic impact of clinical and virological features and to develop a specific prognostic score for this subset of patients. All prognostic evaluations were performed on 535 patients treated with an anthracycline-based induction regimen (with rituximab in 255 cases). Severe hepatotoxicity was observed in 14% of patients. The use of rituximab was not associated with increased rate of severe hepatotoxicity. Three-year overall survival and progression-free survival were 71% and 55%, respectively. At multivariate analysis, ECOG performance status of 2 or over, serum albumin below 3.5 g/dL and HCV-RNA viral load over 1000 KIU/mL retained prognostic significance. We combined these 3 factors in a new “HCV Prognostic Score” able to discriminate 3 risk categories with different overall and progression-free survival (low=0; intermediate=1; high-risk ≥2 factors; P<0.001). This score retained prognostic value in the subgroups of patients treated with and without rituximab (P<0.001). The new score performed better than the International Prognostic Index at multivariate analysis and Harrel C-statistic. With the use of three readily available factors (performance status, albumin level and HCV-RNA viral load), the new “HCV Prognostic Score” is able to identify 3 risk categories with different survival, and may be a useful tool to predict the outcome of hepatitis C virus-associated diffuse large B-cell lymphomas.

Splenic marginal zone lymphoma: Clinical clustering of immunoglobulin heavy chain repertoires

Immunoglobulin gene usage and somatic mutation patterns were studied in 59 patients with splenic marginal zone lymphoma and were correlated with clinical characteristics. Fifty-nine IGHV rearrangements were amplified. IGHV1, IGHV3, and IGHV4 subgroups accounted for 30%, 56%, and 14% of sequences, respectively. IGHV genes most frequently used were IGHV1-2 (n=12), IGHV3-23 (n=15), IGHV3-30 (n=7) and IGHV4-34 (n=5). IGHV was unmutated in 25%. Villous lymphocytes >10% were detected in 50% of patients belonging to the IGHV1-2 group, in 21% of the IGHV3-23 group, and in no patient of the IGHV3-30 group (p=0.05). Liver involvement was present in 50% of the IGHV3-30 group, in 9% of the IGHV3-23 group, and in no patient of the IGHV1-2 group (p=0.04). HCV-serology was positive in 50% of the IGHV3-30 group, in 7% of the IGHV3-23 group, and in 17% of the IGHV1-2 group (p=0.04). The proportion of intermediate and high risk patients according to the SMZL score was higher in the unmutated respect to the mutated group (69% vs 32%, p=0.05). In conclusion, IGHV rearrangement analysis in splenic marginal zone B-cell lymphoma reveals a non-random preference for use of IGHV1-2, IGHV3-23 and IGHV3-30 genes, whose presence differs according to clinical features and prognostic category.