Some epidemiologic studies suggest a link between hepatitis C virus (HCV) infection and some B-cell non-Hodgkin's lymphomas. We undertook this study after a patient with splenic lymphoma with villous lymphocytes had a hematologic response after antiviral treatment of HCV infection. Nine patients who had splenic lymphoma with villous lymphocytes and HCV infection were treated with interferon alfa-2b (3 million IU three times per week) alone or in combination with ribavirin (1000 to 1200 mg per day). The outcomes were compared with those of six similarly treated patients with splenic lymphoma with villous lymphocytes who tested negative for HCV infection. Of the nine patients with HCV infection who received interferon alfa, seven had a complete remission after the loss of detectable HCV RNA. The other two patients had a partial and a complete remission after the addition of ribavirin and the loss of detectable HCV RNA. One patient had a relapse when the HCV RNA load again became detectable in blood. In contrast, none of the six HCV-negative patients had a response to interferon therapy. In patients with splenic lymphoma with villous lymphocytes who are infected with HCV, treatment with interferon can lead to regression of the lymphoma.

Although a classification for mastocytosis and diagnostic criteria are available, there remains a need to define standards for the application of diagnostic tests, clinical evaluations, and treatment responses. To address these demands, leading experts discussed current issues and standards in mastocytosis in a Working Conference. The present article provides the resulting outcome with consensus statements, which focus on the appropriate application of clinical and laboratory tests, patient selection for interventional therapy, and the selection of appropriate drugs. In addition, treatment response criteria for the various clinical conditions, disease‐specific symptoms, and specific pathologies are provided. Resulting recommendations and algorithms should greatly facilitate the management of patients with mastocytosis in clinical practice, selection of patients for therapies, and the conduct of clinical trials.

Coronavirus disease 2019 (COVID-19) is a respiratory disease induced by a novel coronavirus (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) causing substantial morbidity and mortality.^1-4 Most people with COVID-19 have only mild or uncomplicated symptoms, but approximately 10% to 15% have moderate or severe disease that requires hospitalization and oxygen support, and 3% to 5% require admission to an intensive care unit (ICU).⁵ In severe cases, COVID-19 can be complicated by acute respiratory distress syndrome (ARDS). Older age, male sex, and comorbid diseases are risk factors for death.^6-8

Adult T-cell leukemia-lymphoma (ATL) is a distinct peripheral T-lymphocytic malignancy associated with a retrovirus designated human T-cell lymphotropic virus type I (HTLV-1). The diversity in clinical features and prognosis of patients with this disease has led to its subclassification into the following four categories: acute, lymphoma, chronic, and smoldering types. The chronic and smoldering subtypes are considered indolent and are usually managed with watchful waiting until disease progression, analogous to the management of some patients with chronic lymphoid leukemia (CLL) or other indolent histology lymphomas. Patients with aggressive ATL generally have a poor prognosis because of multidrug resistance of malignant cells, a large tumor burden with multiorgan failure, hypercalcemia, and/or frequent infectious complications as a result of a profound T-cell immunodeficiency. Under the sponsorship of the 13th International Conference on Human Retrovirology: HTLV, a group of ATL researchers joined to form a consensus statement based on established data to define prognostic factors, clinical subclassifications, and treatment strategies. A set of response criteria specific for ATL reflecting a combination of those for lymphoma and CLL was proposed. Clinical subclassification is useful but is limited because of the diverse prognosis among each subtype. Molecular abnormalities within the host genome, such as tumor suppressor genes, may account for these diversities. A treatment strategy based on the clinical subclassification and prognostic factors is suggested, including watchful waiting approach, chemotherapy, antiviral therapy, allogeneic hematopoietic stem-cell transplantation (alloHSCT), and targeted therapies.

Advanced systemic mastocytosis comprises rare hematologic neoplasms that are associated with a poor prognosis and lack effective treatment options. The multikinase inhibitor midostaurin inhibits KIT D816V, a primary driver of disease pathogenesis. We conducted an open-label study of oral midostaurin at a dose of 100 mg twice daily in 116 patients, of whom 89 with mastocytosis-related organ damage were eligible for inclusion in the primary efficacy population; 16 had aggressive systemic mastocytosis, 57 had systemic mastocytosis with an associated hematologic neoplasm, and 16 had mast-cell leukemia. The primary outcome was the best overall response. The overall response rate was 60% (95% confidence interval [CI], 49 to 70); 45% of the patients had a major response, which was defined as complete resolution of at least one type of mastocytosis-related organ damage. Response rates were similar regardless of the subtype of advanced systemic mastocytosis, KIT mutation status, or exposure to previous therapy. The median best percentage changes in bone marrow mast-cell burden and serum tryptase level were −59% and −58%, respectively. The median overall survival was 28.7 months, and the median progression-free survival was 14.1 months. Among the 16 patients with mast-cell leukemia, the median overall survival was 9.4 months (95% CI, 7.5 to not estimated). Dose reduction owing to toxic effects occurred in 56% of the patients; re-escalation to the starting dose was feasible in 32% of those patients. The most frequent adverse events were low-grade nausea, vomiting, and diarrhea. New or worsening grade 3 or 4 neutropenia, anemia, and thrombocytopenia occurred in 24%, 41%, and 29% of the patients, respectively, mostly in those with preexisting cytopenias. In this open-label study, midostaurin showed efficacy in patients with advanced systemic mastocytosis, including the highly fatal variant mast-cell leukemia. (Funded by Novartis Pharmaceuticals and others; ClinicalTrials.gov number, NCT00782067.)