CD79B mutations in primary vitreoretinal lymphoma: Diagnostic and prognostic potential.

OBJECTIVE: Primary vitreoretinal lymphoma (PVRL) is a rare type of lymphoma wherein the lesions are limited to the eyes. PVRL is difficult to diagnose because of the challenges related to obtaining sufficient samples for biopsy. Moreover, PVRL has poor outcomes and often leads to the development of central nervous system (CNS) lesions during its course. Two studies recently reported that approximately 70%-80% of patients with vitreoretinal lymphoma have MYD88L265P , which is frequently mutated in primary CNS lymphoma (PCNSL). PCNSL is closely associated with PVRL. The mutation of CD79BY196 has been also frequently detected in PCNSL. Thus, we examined the mutation in PVRL to clarify its diagnostic and prognostic potential. METHOD: By using direct sequencing and allele-specific polymerase chain reaction, we examined the mutation of CD79BY196 and MYD88L265P in the DNA extracted from the vitreous fluid of 17 patients with PVRL upon diagnosis. We also retrospectively analyzed their prognostic potential for PVRL. RESULTS: Among the included patients, six patients (35%) were found with CD79BY196 mutations. Twelve (71%) patients were positive for MYD88L265P , and six samples from patients with benign uveitis were negative for both mutations. Interestingly, six patients with CD79BY196 mutations developed CNS diseases significantly earlier (16.5 months) than 11 patients with CD79BWT (67 months; P = 0.0135). CONCLUSION: Detecting CD79BY196 in vitreous DNA may contribute to the confirmation of the diagnosis and may have a prognostic potential for patients with PVRL.

High-dose methotrexate following intravitreal methotrexate administration in preventing central nervous system involvement of primary intraocular lymphoma.

In order to prevent central nervous system (CNS) involvement and improve the prognosis of primary intraocular lymphoma (PIOL), we prospectively evaluated the efficacy of combined therapy using intravitreal methotrexate (MTX) and systemic high-dose MTX on treatment-naïve PIOL. Patients with newly diagnosed PIOL whose lymphoma was limited to the eyes were enrolled. The patients were treated with weekly intravitreal MTX until the ocular lesions were resolved, followed by five cycles of systemic high-dose MTX (3.5 g/m2 ) every other week. Ten patients were enrolled in this study and completed the treatment. All patients achieved complete response for their ocular lesions with rapid decrease of intravitreal interleukin-10 concentration. Adverse events of intravitreal and systemic high-dose MTX were mild and tolerable. With a median follow-up of 29.5 months, four patients (40%) experienced the CNS disease development and the mean CNS lymphoma-free survival (CLFS) time was 51.1 months. Two-year CLFS, which was the primary end-point of the study, was 58.3% (95% confidence interval, 23.0-82.1%). In contrast, eight patients were treated with intravitreal MTX alone in our institute, and their 2-year CLFS was 37.5% (95% confidence interval, 8.7-67.4%). In conclusion, systemic high-dose MTX following intravitreal MTX is feasible and might be effective in preventing CNS involvement of PIOL. Further arrangements are worth considering in order to improve the effects. This study was registered with UMIN Clinical Trials Registry (UMIN000003921).

[Fulminant visceral disseminated varicella-zoster virus infection without skin involvement in a patient with autoimmune hemolytic anemia on prednisolone therapy].

An 80-year-old man with autoimmune hemolytic anemia (AIHA) received immunosuppressive therapy with prednisolone (1 mg/kg). One month later, his hemoglobin level had normalized, and the prednisolone dose was tapered. The next day, he complained of acute and progressive back pain. He was admitted to our hospital for further examination approximately 24 h after the pain had started. Computed tomography revealed only localized pneumonia. However, he showed signs of severe disseminated intravascular coagulation (DIC), liver dysfunction, and respiratory failure. Empiric broad-spectrum antibacterial therapy was started with a presumptive diagnosis of severe bacterial infection. However, his condition rapidly deteriorated, and he died 17 h after admission. Varicella-zoster virus (VZV) was detected by quantitative PCR in the peripheral blood sample and by immunohistochemistry in all organs except for the brain at autopsy. Visceral VZV infection is a severe disease with a high mortality rate. Although appropriate diagnosis and treatment is crucial, in cases without the characteristic skin rash the diagnosis is difficult. The possibility of visceral VZV infection should be taken into consideration when administering prednisolone to patients with AIHA.

A novel variant form of MLL-ELL fusion transcript with t(11;19)(q23;p13.1) in chronic myelomonocytic leukemia transforming to acute myeloid leukemia.

MLL located at 11q23 is fused with a variety of partner genes by recurrent chromosomal translocations in acute leukemias. ELL, the MLL partner gene located on chromosome 19p13.1, encodes an RNA polymerase II transcriptional elongation factor, which also possesses the N-terminal region involved in the inhibition of transcription initiation. Here we report a case of chronic myelomonocytic leukemia (CMML) with a 46,XY,t(11;19)(q23;p13.1) karyotype that transformed to acute myeloid leukemia (AML) without showing any karyotypic evolution. Interphase fluorescent in situ hybridization analysis showed the split MLL signals in 95% of bone marrow cells when the diagnosis of CMML was made and the percentage of blasts was 1.2%. Sequence analysis of reverse-transcriptional polymerase chain reaction product revealed a novel variant form of MLL-ELL transcript in which MLL exon 10 was fused to ELL exon 3. MLL has been fused to ELL exon 2 in all the previously reported MLL-ELL transcripts, which have always been associated with AML. It is deduced that the variant form of MLL-ELL may be defective not only in inhibition of transcription initiation, but also in transcriptional elongation. Thus, a possibility is raised that the unique clinical presentation of the present case with t(11;19)(q23;p13.1) might be related to the variant form of MLL-ELL.

A variant-type MLL/SEPT9 fusion transcript in adult de novo acute monocytic leukemia (M5b) with t(11;17)(q23;q25).

As a result of recurrent chromosomal translocations in acute leukemias, the mixed-lineage-leukemia (MLL) gene fuses with a variety of partner genes, which include several members of the septin gene family. SEPT9 is a very rare but recurrent fusion partner of MLL, and has recently been implicated in the oncogenesis of various malignancies. Herein, we report a case of de novo acute monocytic leukemia (M5b) with t(11;17)(q23;q25). MLL involvement was revealed by fluorescent in situ hybridization (FISH) analysis, and an MLL/SEP9 fusion transcript was detected by RT-PCR. Sequencing analysis further showed that, in contrast to originally reported cases, MLL exon 8 was fused not with SEPT9 exon 3 but with exon 2, which codes for the unique N-terminal region of the SEPT9_v1 isoform, the region implicated in the regulation of gene expression and cell proliferation. We did not detect any mutation of FLT3, which was expressed at a relatively low level in the leukemic cells. Relapsing after a very short complete remission, the leukemia progressed rapidly and became fatal in spite of intensive therapies including hematopoietic stem cell transplantation. It is thus suggested that, in common with the original MLL/SEPT9 cases, monocytic differentiation and a poor prognosis may also be associated with acute myeloid leukemia with the variant MLL/SEPT9 fusion transcript.

IRF4 negatively regulates proliferation of germinal center B cell-derived Burkitt's lymphoma cell lines and induces differentiation toward plasma cells.

To investigate the roles of interferon regulatory factor 4 (IRF4) in B-cell development, we established germinal center B cell-derived Burkitt's lymphoma cell lines that exogenously express IRF4. Daudi-IRF4 expressed IRF4 in the presence of doxycycline (inducible expression), and Raji-IRF4 constitutively expressed an IRF4-estrogen receptor chimeric protein, which was activated by 4-hydroxytamoxifen. Expression or activation of IRF4 resulted in growth inhibition accompanied by accumulation of cells in G0/G1. Upregulation of the plasma cell markers CD38 and CD138 and downregulation of the germinal center cell marker B-cell lymphoma 6 (BCL6) were also observed. Furthermore, mRNAs for BCL6 and paired box gene 5 (PAX5) were decreased and those for B-lymphocyte-induced maturation protein-1 (BLIMP1)/PR domain containing 1 (PRDM1) and X-box binding protein 1 (XBP1) were increased, which corresponds to the characteristic changes in transcription factor expression in B cells differentiating toward plasma cells. Impairment in proliferation and differentiation toward plasma cells induced by IRF4 were not inhibited by enforced expression of BCL6. These results suggest that IRF4 inhibits cell cycle progression of germinal center B cell-derived Burkitt's lymphoma cells and induces terminal differentiation toward plasma cells through mechanisms independent of BCL6 downregulation.

[Bortezomib-induced tumor lysis syndrome with a remarkable elevation of LDH in a case of relapsed and therapy-resistant multiple myeloma].

A 60-year-old female patient with a therapy-resistant Bence-Jones (BJ) lambda-type multiple myeloma was treated with bortezomib. She had been treated with tandem autologous stem cell transplantations and achieved complete remission before her disease relapsed. Sixteen hours after the first administration of bortezomib, an episode of fever, slight consciousness disturbance and vomiting occurred, which was accompanied by a remarkable elevation of LDH (3608 IU/l). Serum levels of creatinine, uric acid, and AST were also transiently elevated. Serum interleukin-6 level was also increased after the administration of bortezomib. The symptoms disappeared rapidly within 48 hours. Bortezomib at a 25%-reduced dose was administered again along with dexamethasone 26 days later, which caused a moderate increase in LDH levels, but no other symptoms. Further treatment caused no increase in LDH. The treatment was very effective and eradicated both urinary BJ protein and bone marrow myeloma cells after 8 sessions of bortezomib administration. These findings suggest that a bortezomib-induced rapid reduction in tumor burden led to tumor lysis syndrome, for which caution is needed when treating myeloma patients with this very effective agent.

[Ischemic colitis following the treatment of acute hemorrhage in a patient with acquired hemophilia A].

A 66-year-old man with hypertension and hyperlipidemia developed a hemorrhagic stomal ulcer and massive hematoma of the face at 4 and 7 months, respectively, after fundusectomy for early gastric cancer. The diagnosis of acquired hemophilia A was made based on the marked prolongation of activated partial thromboplastin time, an extremely low factor VIII activity, and a very high-titer factor VIII inhibitor. After admission, oral prednisolone and cyclophosphamide were started. In addition, activated prothrombin complex concentrates and recombinant activated factor VII were intravenously administered which successfully controlled his hemorrhage. Only 1 week after the episode of bleeding, however, he complained of abdominal pain accompanied by watery stool with fresh blood. The diagnosis of ischemic colitis was made based on the clinical course and the findings on both CT-scan and colon fiberoscopy. The colitis spontaneously and quickly resolved with conservative observation. To the best of our knowledge, this is the first reported case of ischemic colitis that occurred in an acquired hemophilia patient without simultaneous administration of coagulation factors or antifibrinolytic agents. We should thus pay attention to the possible occurrence of thrombotic events even in acquired hemophilia patients in the presence of risk factors for thrombosis.

[Successful treatment with drainage of hematoma and chemotherapy in a case of Burkitt leukemia presenting with subdural hematoma].

A 53-year-old male was admitted because of pancytopenia and chronic subdural hematoma. Bone marrow was hypercellular with 97% blasts, which expressed CD10, CD19, CD20, and immunoglobulin mu and gamma chains on the cell surface and had chromosomal abnormalities including t(8 ; 22)(q24 ; q11). The patient was diagnosed as having Burkitt leukemia. Because hemiplegia and disturbance of consciousness developed rapidly, the patient was treated with an emergency drainage operation followed by Hyper-CVAD therapy and achieved a sustained complete remission. Dural infiltration of leukemic cells as well as thrombocytopenia was implicated in the pathogenesis of the subdural hematoma, which contained numerous blasts.

[An abdominal follicular dendritic cell tumor in Castleman's disease].

A 57-year-old man was referred to our hospital because of elevated ALP. CT and MRI scans together with abdominal angiography showed multiple masses in his abdomen and portal vein obstruction. A diagnostic laparoscopic examination revealed a tumor of 3 cm x 3 cm near the portal vein and para-aortic lymphadenopathy. Histopathological examination of the tumor showed abnormal follicles with poorly formed germinal centers, scattered large spindle cells with proliferation of small lymphocytes, and hypervascular interfollicular tissue. The spindle cells were positive for follicular dendritic cell markers CD21, CD35, and epithelial membrane antigen. The diagnosis was made of a follicular dendritic cell (FDC) tumor in Castleman's disease (CD) of the hyaline-vascular type. Although the portal vein was obstructed by the FDC tumor, blood flow to the liver was retained by collateral vein. The patient did not show any response to four courses of CHOP therapy and died of obstructive jaundice, biliary tract infection and sepsis. So far, 17 cases of FDC tumor complicating CD have been reported, with a poor prognosis in all cases.

Secondary near-tetraploidy with double der(15)t(15;17) in acute promyelocytic leukemia in relapse.

Tetraploidy or near-tetraploidy is a rare cytogenetic abnormality in acute myelocytic leukemia. We report here a case of acute promyelocytic leukemia that showed near-tetraploidy with double der(15)t(15;17) the leukemia relapsed. At diagnosis, cytogenetic analysis failed to reveal any karyotypic abnormality; however, a promyelocytic leukemia-retinoic acid receptor alpha (PML/RARA) fusion transcript of the bcr3-type was detected with reverse transcriptase-polymerase chain reaction analysis, and a single PML/RARA fusion signal was observed with fluorescence in situ hybridization analysis. At the first relapse, the majority of leukemic cells showed pseudodiploid karyotypes with der(15)t(15;17), as well as additional chromosomal abnormalities, and exhibited a single PML/RARA fusion signal. A small fraction of leukemic cells, however, showed near-tetraploid karyotypes with double der(15)t(15;17), as well as some additional chromosomal abnormalities in common with the pseudodiploid clones, and exhibited double PML/RARA fusion signals. At the second and third relapses, leukemic cells with near-tetraploidy and double PML/RARA fusion signals became predominant. The PML/RARA fusion transcript of the bcr3 type was also observed at each relapse. In addition, Southern blot analysis of the RARA gene at diagnosis and at the second relapse showed a common rearranged band. Notably, giant, bizarre, and hypogranular promyelocytes expressing CD2, CD34, and HLA-DR appeared at the first relapse and became predominant at the second and third relapses. These observations indicate that the APL cells with near-tetraploidy and double der(15)t(15;17) clonally evolved from the pseudodiploid leukemic cells and exhibited the bizarre morphology and aberrant surface immunophenotypes.

T-cell prolymphocytic leukemia with der(11)t(1;11)(q21;q23) and ATM deficiency.

T-cell prolymphocytic leukemia (T-PLL) is a rare mature T-cell malignancy and is similar to a mature T-cell leukemia seen in some patients with ataxia telangiectasia, which is a recessive hereditary chromosomal instability syndrome caused by mutations of the ataxia telangiectasia mutated (ATM) gene located on 11q23. Intriguingly, recent studies have strongly implicated ATM in the pathogenesis of T-PLL as a tumor suppressor gene, because biallelic inactivation of ATM is frequently observed in this disease; however, translocations involving 11q23 have rarely been reported in T-PLL. We report here a case of T-PLL with der(11)t(1;11)(q21;q23). Southern blot analysis did not reveal any abnormality of ATM, nor of MLL, which is also located on 11q23 and is involved in t(1;11)(q21;q23) in acute myelomonocytic leukemia. Northern blot analysis further showed that the ATM transcript of normal size is expressed in the leukemic cells at a level higher than that in normal peripheral blood lymphocytes. Western blot analysis, however, revealed that expression of ATM in the leukemic cells is much lower than that in normal lymphocytes. These results imply that translation of the ATM transcript is impaired or that the ATM protein is highly unstable in the leukemic cells, thus suggesting the presence of nucleotide changes in both alleles.

BCL6 overexpression prevents increase in reactive oxygen species and inhibits apoptosis induced by chemotherapeutic reagents in B-cell lymphoma cells.

Chromosomal translocations and somatic mutations occurring in the 5' noncoding region of the BCL6 gene, encoding a transcriptional repressor, are most frequent genetic abnormalities associated with non-Hodgkin B-cell lymphoma and result in deregulated expression of BCL6. However, the significance of deregulated expression of BCL6 in lymphomagenesis and its effect on clinical outcomes of lymphoma patients have remained elusive. In the present study, we established Daudi and Raji B-cell lymphoma cell lines that overexpress BCL6 or its mutant, BCL6-Ala333/343, in which serine residues required for degradation through the proteasome pathway in B-cell receptor-stimulated cells are mutated. BCL6 overexpression did not have any significant effect on cell proliferation, but significantly inhibited apoptosis caused by etoposide, which induced a proteasome-dependent degradation of BCL6. BCL6-Ala333/343 was not degraded after etoposide treatment and strongly inhibited apoptosis. In these lymphoma cell lines, etoposide increased the generation of reactive oxygen species (ROS) and reduced mitochondria membrane potential, both of which were inhibited by the antioxidant N-acetyl-L-cysteine (NAC). NAC also inhibited apoptosis. Furthermore, BCL6 overexpression was found to inhibit the increase in ROS levels and apoptosis in response to etoposide and other chemotherapeutic reagents. These results raise the possibility that deregulated expression of BCL6 may endow lymphoma cells with resistance to chemotherapeutic reagents, most likely by enhancing the antioxidant defense systems.

[Late appearance of Philadelphia chromosome with the p190 BCR/ABL chimeric transcript in acute myelogenous leukemia progressing from myelodysplastic syndrome].

We report a late appearance of the Philadelphia chromosome (Ph) with the p190 BCR/ABL chimeric transcript in a 69-year-old patient with acute myelogenous leukemia (AML) that had evolved from myelodysplastic syndrome (MDS). In July 1997, the patient was found to have pancytopenia caused by refractory anemia with excess of blasts, which evolved into AML in 4 months. The leukemic cells were positive for CD13, CD14, CD33, and HLA-DR and had a normal karyotype. The patient achieved a complete remission after combination chemotherapy. However, his leukemia relapsed in November 1999, with the appearance of leukemic cells positive for CD7, CD13, CD34, and HLA-DR with a 46, XY, add (18) (p11) karyotype. The patient failed to achieve the second remission after several courses of intensive chemotherapy. When the number of blastic cells, showing the same surface phenotypes, in the peripheral blood increased drastically in April 2000, chromosomal analysis of leukemic cells revealed a 46, XY, t(9;22) (q34;q11), add(18)(p11) karyotype. The fusion of the BCR and ABL genes was confirmed by fluorescence in situ hybridization analysis, and the reverse transcription-polymerase chain reaction analysis further revealed the presence of the p190 BCR/ABL chimeric transcript. The appearance of the Ph chromosome in the course of MDS transforming to AML is very rare and may be correlated to the disease progression.

[Hypercalcemia mediated by parathyroid hormone-related protein in the blastic phase of chronic myelogenous leukemia].

A 45-year-old man with chronic myelogenous leukemia (CML) in the accelerated phase was admitted to our hospital because of lower back pain and hypercalcemia. On admission, he was confused and found to have massive splenomegaly. The hypercalcemia and splenomegaly improved significantly after administration of incadronate, hydroxyurea, vincristine and prednisolone. Splenomegaly recurred after cessation of the chemotherapy, and examination of the peripheral blood showed 31% blasts, positive for both CD13 and CD33, on which basis myeloid blastic transformation was diagnosed. Vindesine, cytarabine and prednisolone were administered, and the splenomegaly improved again. On admission, when the patient's serum calcium level was 16.0 mg/dl, his serum parathyroid hormone-related protein (PTHrP) level was elevated to 118.3 pmol/l. Furthermore, RT-PCR analysis revealed that the patient's CML cells expressed PTHrP mRNA, and a high level of PTHrP was detected in the supernatant of cultured mononuclear cells derived from the patient's peripheral blood. These findings indicated that the hypercalcemia was due to production of PTHrP by the leukemic cells. Several cases of PTHrP. mediated hypercalcemia associated with CML have been reported previously, and are reviewed here.

Cloning and characterization of the human BAZF gene, a homologue of the BCL6 oncogene.

The BAZF gene has recently been identified as a novel homologue of the BCL6 oncogene. Here we cloned the human BAZF gene using murine BAZF as a probe. The predicted amino acid sequence was 91% identical to that of murine BAZF. The BTB/POZ and zinc finger domains were almost completely conserved between human and murine BAZF. Fluorescence in situ hybridization analysis revealed that the human BAZF gene is located on chromosome 17p13.1. Although expression of human BAZF mRNA was ubiquitously detected in human tissues, abundant expression was detected in heart and placenta. BAZF mRNA was expressed in some immature B cell lines and erythroleukemia cell lines. The expression in a human erythroleukemia cell line, HEL cells, was upregulated during megakaryocytic differentiation induced by 12-O-tetradecanoyl-phorbol-13-acetate. These expression patterns of BAZF mRNA suggest that BAZF may regulate differentiation in stages or lineages that are different from those regulated by BCL6.