Dasatinib-induced colitis: clinical, endoscopic and histological findings.

BACKGROUND: Dasatinib, a second-generation tyrosine kinase inhibitor, is widely used in patients with haematological malignancies. The main side effects of dasatinib are myelosuppression and pleural effusion; however, colitis, such as haemorrhagic colitis and cytomegalovirus (CMV) colitis, have been reported as rare side effects. There are only a few studies conducted on dasatinib-induced colitis. AIMS: This study aimed to clarify the clinical, endoscopic and pathological features of dasatinib-induced colitis. METHODS: This retrospective study included 51 consecutive patients who received dasatinib therapy between June 2009 and July 2020. Dasatinib-induced colitis was defined as the presence of colitis symptoms, exclusion of other diseases that could cause colitis, and improvement in symptoms after dasatinib withdrawal or dose reduction. CMV positivity was determined based on the positive result of CMV immunostaining. RESULTS: Dasatinib-induced colitis was diagnosed in nine of 51 patients (17.6%), and most of the symptoms were mild diarrhoea and bloody stools. The endoscopic findings were characterised by loss of vascular pattern (100%) and multiple small erosions (83.3%) which were mainly found in the transverse and descending colon. In a patient who underwent follow-up colonoscopy once a year while taking dasatinib, endoscopic findings changed from initial erythematous spots to multiple erosions, and finally to multiple small round elevations with erosion on the top that disappeared after discontinuation of dasatinib. Anti-CMV therapy was administered to one patient, but the treatment failed. All patients with dasatinib-induced colitis were cured after the discontinuation of dasatinib. CONCLUSION: Physicians should consider CMV reactivation to manage dasatinib-induced colitis.

[Effective treatment with rituximab for primary thrombotic thrombocytopenic purpura complicated with multiple cerebral infarctions].

A 22-year-old woman was diagnosed with thrombotic thrombocytopenic purpura (TTP). She had a high fever and disorientation without renal dysfunction. She immediately underwent plasma exchange and prednisolone treatment, but they proved ineffective. She subsequently suffered from left major cerebral infarction with right-side hemiplegia. Therefore, 375 mg/m(2) of rituximab was administered weekly from day 14 with informed consent. Immediate improvements were noted in not only the hematological and biochemical parameters such as platelet count, hemoglobin level, rate of fragmented red cells, and serum LDH level but also the neurological symptoms and MRI findings. The universal histopathologic findings of TTP are characterized by hyaline thrombi formed by the aggregation of platelets, mostly in small arterioles and capillaries. Therefore, abnormal findings are rarely detected by imaging modalities such as CT and MRI. Moreover, TTP with major stroke is an extremely rare occurrence. In conclusion, we present a patient with refractory TTP with major cerebral infarction, who was effectively treated with rituximab.

Treatment outcomes of chronic-phase chronic myeloid leukemia with resistance and/or intolerance to a 1st-line tyrosine kinase inhibitor in Japan: the results of the New TARGET study 2nd-line.

We herein report the results of the New TARGET study 2nd-line, which collected data on patients with chronic-phase (CP) chronic myeloid leukemia (CML) who received a 2nd-line tyrosine kinase inhibitor (TKI) because of resistance and/or to a 1st-line TKI. A total of 98 patients were enrolled intolerance between April 2010 and March 2013, and 82 patients were analyzed. The median age was 54 years (range 22-88 years). Seventy-six patients (93%) received imatinib as the 1st-line TKI. Forty-five (55%) and 37 (45%) patients began nilotinib and dasatinib treatments at entry, respectively. First-line TKI treatment achieved complete hematological response in 79 patients (96%) and complete cytogenetic response (CCyR) in 49 patients (60%), respectively. Nine patients (11%) had BCR-ABL1 kinase domain point mutations at enrollment. The estimated 3-year progression-free-survival rate after enrollment was 98.7% (95% CI 91.1-99.8%). Overall, the probabilities of achieving CCyR and a major molecular response were 89.3% (95% CI 81.4-94.8%) and 87.2% (95% CI 78.1-93.8%), respectively. There were no new safety issues. This study demonstrated that CML-CP patients in Japan who are resistant and/or intolerant to a 1st-line TKI can achieve an extremely good outcome by 2nd-line TKI treatment.

[Long-term remission of non-Hodgkin lymphoma secondary to the treatment for essential thrombocythemia].

A 45-year-old woman was diagnosed with essential thrombocythemia (ET) in August 1987 and received treatment with alkylating agents (total administration dose, busulfan 378 mg, MCNU 700 mg) because of a history of myocardial infarction. In June 2000, anemia gradually progressed. A few blast cells were detected in the peripheral blood at that time. Since bone marrow biopsy revealed myelofibrosis, she received anabolic hormone therapy. She was admitted to our hospital for an evaluation of abdominal distension in February 2003. Swelling of a large paraaortic lymph node of 6 cm in diameter was detected by CT scan. Lymph node biopsy revealed diffuse large B-cell lymphoma. Lymphoma cells were positive for CD10, CD19, CD20 and kappa-chain. The clinical stage was I. Complete remission has been achieved for 57 months after treatment with combination chemotherapy combined with rituximab followed by local radiation therapy. Non-Hodgkin lymphoma secondary to ET is a rare event. Such cases should therefore be accumulated to evaluate the mechanism of onset and clinical characteristics of lymphoma secondary to ET.

[Sub-classification of diffuse large B-cell lymphoma by semi-quantification of the CD5 expression with flow cytometric analysis].

CD5+ diffuse large B-cell lymphoma(CD5+DLBCL) is known to have different characteristics than CD5-DLBCL and mantle cell lymphoma(MCL). 9 patients with CD5+DLBCL were reviewed, and the results were compared with those of 8 CD5-DLBCL and 3 cyclin D1+MCL patients. CD5+DLBCL was more closely related to many aggressive clinical features or parameters than CD5-DLBCL: 67% of the patients were older than 60 years, 67% with performance status > or = 2, 89% with serum lactate dehydrogenase level higher than normal, 78% with stage III/IV disease at diagnosis, and 78% with more than one extranodal lesion. The overall International Prognostic Index score for the patients with CD5+DLBCL was thus significantly higher than that for those with CD5-DLBCL. Immunophenotypically, CD5+DLBCL was characterized by CD5+CD10-CD19+CD20+CD21-CD23-cyclin D1-phenotype and the predominant expression of surface IgM. Of particular interest is that the survival rate of CD5+DLBCL patients was significantly inferior to that of patients with CD5-DLBCL. To further characterize CD5+DLBCL, we semi-quantified the CD5 expression in DLBCL cells. Our findings suggest that CD5+DLBCL may constitute a unique subgroup of DLBCL and, moreover, CD5+DLBCL may consist of several subgroups.

Tyrosine phosphorylation of a novel 100-kDa protein coupled to CD28 in resting human T cells is enhanced by a signal through TCR/CD3 complex.

For T cell activation, two signals are required, i.e., a T cell receptor (TCR)/CD3-mediated main signal and a CD28-mediated costimulatory signal. CD28 binds to its ligand (CD80 or CD86) and transduces the most important costimulatory signal. The cytoplasmic domain of the CD28 molecule, composed of 41 amino acids, does not contain any intrinsic enzyme activity. The cytoplasmic domain of CD28 is remarkably conserved among species and is associated with a number of signaling molecules that affect the main signal. We report here that a tyrosine phosphorylated 100-kDa protein (ppl00) was coupled to the CD28 cytoplasmic domain in Jurkat and human peripheral T cells. The pp100 was distinguished from other CD28 associated molecules such as Vav, STAT5, PI 3-kinase, Valosin-containing protein (VCP), Nucleolin, Gab2 (Grb2-associated binding protein 2), and STAT6. The tyrosine phosphorylation of pp100 coprecipitated with CD28 was enhanced by CD3 stimulation by the specific antibody, tyrosine phosphatase inhibitor and PKC activator. Tyrosine phosphorylation of pp100 was attenuated by the prior addition of PKC inhibitor. These findings indicate that pp100 is a novel tyrosine phosphorylated protein coupled to CD28 under continuous control of tyrosine phosphatases and might play a role in T cell activation augmented by a TCR/CD3-mediated main signal.