SETD2 and histone H3 lysine 36 methylation deficiency in advanced systemic mastocytosis.

The molecular basis of advanced systemic mastocytosis (SM) is not fully understood and despite novel therapies the prognosis remains dismal. Exome sequencing of an index-patient with mast cell leukemia (MCL) uncovered biallelic loss-of-function mutations in the SETD2 histone methyltransferase gene. Copy-neutral loss-of-heterozygosity at 3p21.3 (where SETD2 maps) was subsequently found in SM patients and prompted us to undertake an in-depth analysis of SETD2 copy number, mutation status, transcript expression and methylation levels, as well as functional studies in the HMC-1 cell line and in a validation cohort of 57 additional cases with SM, including MCL, aggressive SM and indolent SM. Reduced or no SETD2 protein expression-and consequently, H3K36 trimethylation-was found in all cases and inversely correlated with disease aggressiveness. Proteasome inhibition rescued SETD2 expression and H3K36 trimethylation and resulted in marked accumulation of ubiquitinated SETD2 in SETD2-deficient patients but not in patients with near-normal SETD2 expression. Bortezomib and, to a lesser extent, AZD1775 alone or in combination with midostaurin induced apoptosis and reduced clonogenic growth of HMC-1 cells and of neoplastic mast cells from advanced SM patients. Our findings may have implications for prognostication of SM patients and for the development of improved treatment approaches in advanced SM.

Serum total tryptase level confirms itself as a more reliable marker of mast cells burden in mast cell leukaemia (aleukaemic variant).

Mast cell leukemia (MCL) is a very rare form of systemic mastocytosis (SM) with a short median survival of 6 months. We describe a case of a 65-year-old woman with aleukaemic variant of MCL with a very high serum total tryptase level of 2255 µg/L at diagnosis, which occurred following an episode of hypotensive shock. She fulfilled the diagnostic criteria of SM, with a bone marrow smear infiltration of 50-60% of atypical mast cells (MCs). She tested negative for the KIT D816V mutation, without any sign of organ damage (no B- or C-findings) and only few mediator-related symptoms. She was treated with antihistamine alone and then with imatinib for the appearance of anemia. She maintained stable tryptase level and a very indolent clinical course for twenty-two months; then, she suddenly progressed to acute MCL with a serum tryptase level up to 12960 µg/L. The patient died due to haemorrhagic diathesis twenty-four months after diagnosis. This clinical case maybe represents an example of the chronic form of mast cell leukemia, described as unpredictable disease, in which the serum total tryptase level has confirmed itself as a reliable marker of mast cells burden regardless of the presence of other signs or symptoms.

Focal nodular hyperplasia after busulfan treatment.

The case of a 48-year-old woman in whom focal nodular hyperplasia of the liver developed after busulfan therapy was administered for essential thrombocytosis is described. Focal nodular hyperplasia is a reactive disorder related to a circulation disorder. The close temporal relation between the haematological disease, busulfan treatment and the appearance of hyperplastic diseases of the liver in our patient supports the possibility that the association of the events might not be casual.

Occult colon cancer in a patient with an unexplained episode of pulmonary embolism.

The association between venous thromboembolism and cancer has been widely documented and the main factor responsible for cancer-induced venous thromboembolism is considered mostly linked to a hypercoagulation state induced by the cancer itself. There is no consensus on investigative strategies for occult cancer in a patient with a thrombophilic condition. We report a patient who manifested an isolated episode of pulmonary embolism without specific evident sources of venous thromboembolism. The routine clinical and laboratory work-up to detect an occult cancer did not reveal any malignancy. A history of duodenal ulcer in association with a recent slight alteration in bowel habits led us to perform an esophagogastroduodenoscopy which was negative for malignancy, and a barium enema followed by colonoscopy, which revealed the presence of a tumor limited to the large intestine. An unexplained clinically evident hypercoagulation state, even in the presence of mild clinical symptoms, needs more thorough diagnostic strategies when simple methods of screening for occult cancer are negative.

Imbalance in corneal redox state during herpes simplex virus 1-induced keratitis in rabbits. Effectiveness of exogenous glutathione supply.

A significant decrease in the antioxidant glutathione (GSH) was found in the corneal tissue of rabbits with Herpes Simplex 1 (HSV-1)-induced keratitis. Such a decrease was due to a loss of the reduced species, since no increase in its oxidized form was observed. Topical administration of purified GSH was able to reduce the virus titre in corneal tissue and, at the same time, was effective in reducing the severity and progression of keratitis and conjunctivitis. This effect was paralleled by a partial recovery in the corneal GSH content. In vitro experiments performed on HSV-1 infected corneal-derived rabbit cells showed that exogenous GSH reduced virus titre in the supernatant of infected cells. These results are in agreement with our previous findings that an oxidative environment, due to GSH depletion, is necessary for virus replication and suggest that topical GSH treatment could be considered as complementary therapy in HSV-1-induced keratitis.

Increased replication of Sendai virus in morphine-treated epithelial cells: evidence for the involvement of the intracellular levels of glutathione.

This paper shows that morphine increases Sendai virus replication in cultured epithelial cells. The effect was maximal when it was added before viral infection. Morphine also reduced the intracellular level of glutathione, namely, the oxidative and most abundant cell thiol. Altered intracellular redox status has recently been proposed as a factor influencing viral infection. Support for this view was provided by our data showing that inhibition of de novo glutathione synthesis, using L-buthionine sulfoximine, increased virus replication. These findings provide the first evidence that morphine increases the susceptibility to virus infection by altering the intracellular levels of glutathione.

Synthesis, cytotoxic effect and antiviral activity of 1-(beta-D-arabinofuranosyl)-5-bromo-N4-substituted cytosine and 1-(beta-D-arabinofuranosyl)-5-bromo-4-methoxypyrimidin-2(1H)-one derivatives.

A convenient and mild synthesis of 5-bromo-N4-substituted-1-(beta-D-arabinofuranosyl)cytosine and 5-bromo-O4-methyl-1-(beta-D-arabinofuranosyl)pyrimidin-2(1H)-one derivatives by selective oxyfunctionalization of the corresponding 4-thionucleosides with 3,3-dimethyldioxirane is reported. The cytotoxicity and the antiviral activity against parainfluenza 1 (Sendai virus) of all new synthesized products are also reported.

A potent and selective inhibition of parainfluenza 1 (Sendai) virus by new 6-oxiranyl-, 6-methyloxiranyluracils, and 4(3H)-pyrimidinone derivatives.

Several new 6-oxiranyl-, 6-methyloxiranyluracils, and pyrimidinone derivatives, synthesized by the lithiation-alkylation sequence of 1,3,6-trimethyluracil, 1,3-dimethyl-6-chloromethyluracil, and 2-alkoxy-6-methyl-4(3H)-pyrimidinones, showed a potent and selective antiviral activity against the parainfluenza 1(Sendai) virus replication.