Genetic basis of lineage-specific evolution of fruit traits in hexaploid persimmon.

Frequent polyploidization events in plants have led to the establishment of many lineage-specific traits representing each species. Little is known about the genetic bases for these specific traits in polyploids, presumably due to plant genomic complexity and their difficulties in applying genetic approaches. Hexaploid Oriental persimmon (Diospyros kaki) has evolved specific fruit characteristics, including wide variations in fruit shapes and astringency. In this study, using whole-genome diploidized/quantitative genotypes from ddRAD-Seq data of 173 persimmon cultivars, we examined their population structures and potential correlations between their structural transitions and variations in nine fruit traits. The population structures of persimmon cultivars were highly randomized and not substantially correlated with the representative fruit traits focused on in this study, except for fruit astringency. With genome-wide association analytic tools considering polyploid alleles, we identified the loci associated with the nine fruit traits; we mainly focused on fruit-shape variations, which have been numerically characterized by principal component analysis of elliptic Fourier descriptors. The genomic regions that putatively underwent selective sweep exhibited no overlap with the loci associated with these persimmon-specific fruit traits. These insights will contribute to understanding the genetic mechanisms by which fruit traits are independently established, possibly due to polyploidization events.

Reinvention of hermaphroditism via activation of a RADIALIS-like gene in hexaploid persimmon.

In flowering plants, different lineages have independently transitioned from the ancestral hermaphroditic state into and out of various sexual systems1. Polyploidizations are often associated with this plasticity in sexual systems2,3. Persimmons (the genus Diospyros) have evolved dioecy via lineage-specific palaeoploidizations. More recently, hexaploid D. kaki has established monoecy and also exhibits reversions from male to hermaphrodite flowers in response to natural environmental signals (natural hermaphroditism, NH), or to artificial cytokinin treatment (artificial hermaphroditism, AH). We sought to identify the molecular pathways underlying these polyploid-specific reversions to hermaphroditism. Co-expression network analyses identified regulatory pathways specific to NH or AH transitions. Surprisingly, the two pathways appeared to be antagonistic, with abscisic acid and cytokinin signalling for NH and AH, respectively. Among the genes common to both pathways leading to hermaphroditic flowers, we identified a small-Myb RADIALIS-like gene, named DkRAD, which is specifically activated in hexaploid D. kaki. Consistently, ectopic overexpression of DkRAD in two model plants resulted in hypergrowth of the gynoecium. These results suggest that production of hermaphrodite flowers via polyploidization depends on DkRAD activation, which is not associated with a loss-of-function within the existing sex determination pathway, but rather represents a new path to (or reinvention of) hermaphroditism.

Physiological Role of Aerobic Fermentation Constitutively Expressed in an Aluminum-Tolerant Cell Line of Tobacco (Nicotiana tabacum).

Aluminum (Al)-tolerant tobacco cell line ALT301 derived from SL (wild-type) hardly exhibits Al-triggered reactive oxygen species (ROS) compared with SL. Molecular mechanism leading to this phenotype was investigated comparatively with SL. Under normal growth condition, metabolome data suggested the activation of glycolysis and lactate fermentation but the repression of the tricarboxylic acid (TCA) cycle in ALT301, namely aerobic fermentation, which seemed to be transcriptionally controlled partly by higher expression of genes encoding lactate dehydrogenase and pyruvate dehydrogenase kinase. Microarray and gene ontology analyses revealed the upregulation of the gene encoding related to APETALA2.3 (RAP2.3)-like protein, one of the group VII ethylene response factors (ERFVIIs), in ALT301. ERFVII transcription factors are known to be key regulators for hypoxia response that promotes substrate-level ATP production by glycolysis and fermentation. ERFVIIs are degraded under normoxia by the N-end rule pathway of proteolysis depending on both oxygen and nitric oxide (NO), and NO is produced mainly by nitrate reductase (NR) in plants. In ALT301, levels of the NR gene expression (NIA2), NR activity and NO production were all lower compared with SL. Consistently, the known effects of NO on respiratory pathways were also repressed in ALT301. Under Al-treatment condition, NO level increased in both lines but was lower in ALT301. These results suggest that the upregulation of the RAP2.3-like gene and the downregulation of the NIA2 gene and resultant NO depletion in ALT301 coordinately enhance aerobic fermentation, which seems to be related to a higher capacity to prevent ROS production in mitochondria under Al stress.

Distinct Functions of Ethylene and ACC in the Basal Land Plant Marchantia polymorpha.

Ethylene is a gaseous phytohormone involved in various physiological processes, including fruit ripening, senescence, root hair development and stress responses. Recent genomics studies have suggested that most homologous genes of ethylene biosynthesis and signaling are conserved from algae to angiosperms, whereas the function and biosynthesis of ethylene remain unknown in basal plants. Here, we examined the physiological effects of ethylene, an ethylene precursor, 1-aminocyclopropane-1-carboxylic acid (ACC) and an inhibitor of ethylene perception, silver thiosulfate (STS), in a basal land plant, Marchantia polymorpha. M. polymorpha plants biosynthesized ethylene, and treatment with high concentrations of ACC slightly promoted ethylene production. ACC remarkably suppressed the growth of thalli (vegetative organs) and rhizoids (root-hair-like cells), whereas exogenous ethylene slightly promoted thallus growth. STS suppressed thallus growth and induced ectopic rhizoid formation on the dorsal surface of thalli. Thus, ACC and ethylene have different effects on the vegetative growth of M. polymorpha. We generated single and double mutants of ACC synthase-like (ACSL) genes, MpACSL1 and MpACSL2. The mutants did not show obvious defects in thallus growth, ACC content and ethylene production, indicating that MpACSL genes are not essential for the vegetative growth and biosynthesis of ACC and ethylene. Gene expression analysis suggested the involvement of MpACSL1 and MpACSL2 in stress responses. Collectively, our results imply ethylene-independent function of ACC and the absence of ACC-mediated ethylene biosynthesis in M. polymorpha.

Genome-wide study on the polysomic genetic factors conferring plasticity of flower sexuality in hexaploid persimmon.

Sexuality is one of the fundamental mechanisms that work towards maintaining genetic diversity within a species. In diploid persimmons (Diospyros spp.), separated sexuality, the presence of separate male and female individuals (dioecy), is controlled by the Y chromosome-encoded small-RNA gene, OGI. On the other hand, sexuality in hexaploid Oriental persimmon (Diospyros kaki) is more plastic, with OGI-bearing genetically male individuals, able to produce both male and female flowers (monoecy). This is thought to be linked to the partial inactivation of OGI by a retrotransposon insertion, resulting in DNA methylation of the OGI promoter region. To identify the genetic factors regulating branch sexual conversion, genome-wide correlation/association analyses were conducted using ddRAD-Seq data from an F1 segregating population, and using both quantitative and diploidized genotypes, respectively. We found that allelic ratio at the Y-chromosomal region, including OGI, was correlated with male conversion based on quantitative genotypes, suggesting that OGI can be activated in cis in a dosage-dependent manner. Genome-wide association analysis based on diploidized genotypes, normalized for the effect of OGI allele dosage, detected three fundamental loci associated with male conversion. These loci underlie candidate genes, which could potentially act epigenetically for the activation of OGI expression.

Low temperature modulates natural peel degreening in lemon fruit independently of endogenous ethylene.

Peel degreening is an important aspect of fruit ripening in many citrus fruit, and previous studies have shown that it can be advanced by ethylene treatment or by low-temperature storage. However, the important regulators and pathways involved in natural peel degreening remain largely unknown. To determine how natural peel degreening is regulated in lemon fruit (Citrus limon), we studied transcriptome and physiochemical changes in the flavedo in response to ethylene treatment and low temperatures. Treatment with ethylene induced rapid peel degreening, which was strongly inhibited by the ethylene antagonist, 1-methylcyclopropene (1-MCP). Compared with 25 ºC, moderately low storage temperatures of 5-20 °C also triggered peel degreening. Surprisingly, repeated 1-MCP treatments failed to inhibit the peel degreening induced by low temperature. Transcriptome analysis revealed that low temperature and ethylene independently regulated genes associated with chlorophyll degradation, carotenoid metabolism, photosystem proteins, phytohormone biosynthesis and signalling, and transcription factors. Peel degreening of fruit on trees occurred in association with drops in ambient temperature, and it coincided with the differential expression of low temperature-regulated genes. In contrast, genes that were uniquely regulated by ethylene showed no significant expression changes during on-tree peel degreening. Based on these findings, we hypothesize that low temperature plays a prominent role in regulating natural peel degreening independently of ethylene in citrus fruit.

Molecular Mechanism Underlying Derepressed Male Production in Hexaploid Persimmon.

Sex expression in plants is often flexible and contributes to the maintenance of genetic diversity within a species. In diploid persimmons (the genus Diospyros), the sexuality is controlled by the Y chromosome-encoded small-RNA gene, OGI, and its autosomal counterpart, MeGI. Hexaploid Oriental persimmon (Diospyros kaki) evolved more flexible sex expression, where genetically male individuals carrying OGI can produce both male and female flowers (monoecy). This is due to (semi-)inactivation of OGI by the Kali-SINE retrotransposon insertion on the promoter region and the resultant DNA methylations. Instead, flower sex determination in Oriental persimmon is also dependent on DNA methylation states of MeGI. Here, we focused on a cultivar, Kumemaru, which shows stable male flower production. Our results demonstrated that cv. Kumemaru carries OGI with Kali-SINE, which was highly methylated as well as in other monoecious cultivars; nevertheless, OGI gene could have a basal expression level. Transcriptomic analysis between cv. Kumemaru and 14 cultivars that predominantly produce female flowers showed differentially expressed genes (DEGs) specific to cv. Kumemaru, which is mainly involved in stress responses. Co-expression gene networks focusing on the DEGs also suggested the involvement of stress signals, mainly via gibberellin (GA), salicylic acid (SA), and especially jasmonic acid (JA) signal pathways. We also identified potential regulators of this co-expression module, represented by the TCP4 transcription factor. Furthermore, we attempted to identify cv. Kumemaru-specific transcript polymorphisms potentially contributing to derepressed OGI expression by cataloging subsequences (k-mers) in the transcriptomic reads from cv. Kumemaru and the other 14 female cultivars. Overall, although the direct genetic factor to activate OGI remains to be solved, our results implied the involvement of stress signals in the release of silenced OGI and the resultant continuous male production.

Low Temperature Storage Stimulates Fruit Softening and Sugar Accumulation Without Ethylene and Aroma Volatile Production in Kiwifruit.

Fruit ripening in response to propylene (an ethylene analog), 1-methylcyclopropene (1-MCP, an ethylene action inhibitor), and low temperature (5°C) treatments was characterized in "Kosui" kiwifruit (Actinidia rufa × A. chinensis). Propylene treatment induced ethylene production, with increased expression levels of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase 1 (AcACS1) and ACC oxidase 2 (AcACO2), and rapid fruit softening together with increased expression levels of polygalacturonase (AcPG) and expansin 1 (AcEXP1) within 5 days (d). Fruit soluble solids concentration (SSC) and contents of sucrose, glucose, and fructose together with the expression levels of ß-amylase 1 (Acß-AMY1), Acß-AMY2, and invertase (AcINV3-1) increased rapidly after 5 d exposure to propylene. Furthermore, propylene exposure for 5 d was sufficient to induce the production of key aroma volatile compounds, ethyl- and methyl butanoate, accompanied with increased expression levels of alcohol acyl transferase (AcAAT). Application of 1-MCP at the start of the experiment, followed by continuous exposure to propylene, significantly delayed fruit softening, changes in SSC and sugars, and strongly suppressed the production of ethylene, aroma volatiles, and expression of associated genes. During storage, fruit softening, SSC and sugar increase, and increased expression of genes associated with cell wall modification and carbohydrate metabolism were registered without detectable ethylene production; however, these changes occurred faster at 5°C compared to 22°C. Interestingly, ethyl and methyl butanoate as well as AcAAT expression were undetectable in kiwifruit during storage, while they were rescued by post-storage propylene exposure, indicating that the production of aroma volatile compounds is strongly ethylene-dependent. Transcript levels of a NAC-related transcription factor (TF), AcNAC3, increased in response to both propylene and low temperature treatments, while AcNAC5 was exclusively up-regulated by propylene. By contrast, transcript levels of a MADS-box TF, AcMADS2, exclusively increased in response to low temperature. The above findings indicate that kiwifruit ripening is inducible by either ethylene or low temperature signals. However, fruit ripened by low temperature were deficient in ethylene-dependent aroma volatiles, suggesting that ethylene signaling is non-functional during low temperature-modulated ripening in kiwifruit. These data provide further evidence that ethylene-dependent and low temperature-modulated ripening in kiwifruit involve different regulatory mechanisms.

[Toxoplasmosis-associated central nervous system vasculitis accompanied by multiple cerebral hemorrhages developing subsequent to cord blood transplantation].

A 57-year-old man with high-risk myelodysplastic syndrome underwent umbilical cord blood transplantation. He began receiving steroids on day 14 for acute graft-versus-host disease, and experienced dizziness on day 75 during gradual dose reduction. Multiple hemorrhages were observed in the cerebrum, cerebellum, and brainstem. His bleeding increased, and he underwent a brain biopsy on day 91. Subsequently, he was diagnosed with central nervous system vasculitis (CNSV) on the basis of the observed aggregation of mature CD3+ lymphocytes around small vessels and vascular wall invasion by lymphocytes and macrophages. After receiving high-dose steroid therapy, cerebral hemorrhage stopped; however, dysphasia occurred on day 113 and the patient died of cerebral edema on day 128. Toxoplasma DNA and tachyzoites were detected in the brain biopsy specimen during additional examinations; therefore, we suspected that the toxoplasmosis was related to the onset of CNSV. CNSV is a rare, rapidly progressing disease that may present as a fatal post-transplantation central nervous system complication. Investigating the causes of CNSV, including CNSV associated with toxoplasmosis, is critically important for improving the prognosis of patients with CNSV.

Comparative transcriptome analysis reveals distinct ethylene-independent regulation of ripening in response to low temperature in kiwifruit.

BACKGROUND: Kiwifruit are classified as climacteric since exogenous ethylene (or its analogue propylene) induces rapid ripening accompanied by ethylene production under positive feedback regulation. However, most of the ripening-associated changes (Phase 1 ripening) in kiwifruit during storage and on-vine occur largely in the absence of any detectable ethylene. This ripening behavior is often attributed to basal levels of system I ethylene, although it is suggested to be modulated by low temperature. RESULTS: To elucidate the mechanisms regulating Phase 1 ripening in kiwifruit, a comparative transcriptome analysis using fruit continuously exposed to propylene (at 20 °C), and during storage at 5 °C and 20 °C was conducted. Propylene exposure induced kiwifruit softening, reduction of titratable acidity (TA), increase in soluble solids content (SSC) and ethylene production within 5 days. During storage, softening and reduction of TA occurred faster in fruit at 5 °C compared to 20 °C although no endogenous ethylene production was detected. Transcriptome analysis revealed 3761 ripening-related differentially expressed genes (DEGs), of which 2742 were up-regulated by propylene while 1058 were up-regulated by low temperature. Propylene exclusively up-regulated 2112 DEGs including those associated with ethylene biosynthesis and ripening such as AcACS1, AcACO2, AcPL1, AcXET1, Acß-GAL, AcAAT, AcERF6 and AcNAC7. Similarly, low temperature exclusively up-regulated 467 DEGS including AcACO3, AcPL2, AcPMEi, AcADH, Acß-AMY2, AcGA2ox2, AcNAC5 and AcbZIP2 among others. A considerable number of DEGs such as AcPG, AcEXP1, AcXET2, Acß-AMY1, AcGA2ox1, AcNAC6, AcMADS1 and AcbZIP1 were up-regulated by either propylene or low temperature. Frequent 1-MCP treatments failed to inhibit the accelerated ripening and up-regulation of associated DEGs by low temperature indicating that the changes were independent of ethylene. On-vine kiwifruit ripening proceeded in the absence of any detectable endogenous ethylene production, and coincided with increased expression of low temperature-responsive DEGs as well as the decrease in environmental temperature. CONCLUSIONS: These results indicate that kiwifruit possess both ethylene-dependent and low temperature-modulated ripening mechanisms that are distinct and independent of each other. The current work provides a foundation for elaborating the control of these two ripening mechanisms in kiwifruit.

Two Members of the Aluminum-Activated Malate Transporter Family, SlALMT4 and SlALMT5, are Expressed during Fruit Development, and the Overexpression of SlALMT5 Alters Organic Acid Contents in Seeds in Tomato (Solanum lycopersicum).

The aluminum-activated malate transporter (ALMT) family of proteins transports malate and/or inorganic anions across plant membranes. To demonstrate the possible role of ALMT genes in tomato fruit development, we focused on SlALMT4 and SlALMT5, the two major genes expressed during fruit development. Predicted proteins were classified into clade 2 of the family, many members of which localize to endomembranes. Tissue-specific gene expression was determined using transgenic tomato expressing the ß-glucuronidase reporter gene controlled by their own promoters. Both the genes were expressed in vascular bundles connecting to developing seeds in fruit and in the embryo of mature seeds. Further, SlALMT5 was expressed in embryo in developing seeds in fruit. Subcellular localization of both proteins to the endoplasmic reticulum (ER) was established by transiently expressing the green fluorescent protein fusions in plant protoplasts. SlALMT5 probably localized to other endomembranes as well. Localization of SlALMT5 to the ER was also confirmed by immunoblot analysis. The transport function of both SlALMT proteins was investigated electrophysiologically in Xenopus oocytes. SlALMT5 transported malate and inorganic anions such as nitrate and chloride, but not citrate. SlALMT4 also transported malate, but the results were less consistent perhaps because it did not localize strongly to the plasma membrane. To elucidate the physiological role of SlALMT5 further, we overexpressed SlALMT5 in tomato. Compared with the wild type, overexpressors exhibited higher malate and citrate contents in mature seeds, but not in fruit. We conclude that the malate transport function of SlALMT5 expressed in developing fruit influences the organic acid contents in mature seeds.

Low-temperature-modulated fruit ripening is independent of ethylene in 'Sanuki Gold' kiwifruit.

Fruit ripening in response to treatments with propylene, 1-methycyclopropene (1-MCP), and low temperature was characterized in 'Sanuki Gold' kiwifruit, Actinidia chinensis Planch. Propylene treatment immediately induced rapid fruit softening, increased AC-PG (polygalacturonase) and AC-EXP (expansin) mRNA accumulation, and stimulated an increase in the soluble solid concentration (SSC) and a decrease in titratable acidity (TA). After 3 d exposure to propylene, ethylene production and AC-PL (pectate lyase) mRNA accumulation were observed. 1-MCP treatment after 24 h exposure to propylene eliminated AC-PG mRNA accumulation and suppressed continued changes in SSC and TA. Application of 1-MCP at the start of the treatment, followed by continuous propylene exposure, markedly delayed fruit softening, and the expression of the cell wall-modifying genes, and changes in the SSC and TA, indicating that kiwifruit become insensitive to ethylene at least for 3 d following 1-MCP exposure. Surprisingly, significant fruit softening, mRNA accumulation of AC-PG, AC-PL, and AC-EXP, and decreased TA were observed without ethylene production in intact fruit stored at low temperature for 1 month, but not in fruit stored at room temperature. Repeated 1-MCP treatments (twice a week) failed to inhibit the changes that occurred in low temperature storage. These observations indicate that low temperature modulates the ripening of kiwifruit in an ethylene-independent manner, suggesting that kiwifruit ripening is inducible by either ethylene or low temperature signals.

A fraction of unripe kiwi fruit extract regulates adipocyte differentiation and function in 3T3-L1 cells.

Adipocyte dysfunction is strongly associated with the development of insulin resistance and diabetes, and regulation of adipogenesis is important in prevention of diabetes. We prepared a 100% methanol fraction of methanolic extract from unripe kiwi fruit (Actinidia deliciosa), designated KMF (kiwi fruit methanol fraction). When applied to 3T3-L1 preadipocyte cells, KMF promoted adipocyte differentiation, increased glycerol-3-phosphate dehydrogenase (GPDH) activity, and increased triglyceride (TG) content. KMF markedly increased mRNA expression of peroxisome proliferator-activated receptor gamma (PPARgamma)-the master adipogenic transcription factor-and its target genes. Moreover, KMF increased mRNA expression and protein secretion of adiponectin, whereas mRNA expression and secretion of monocyte chemoattractant protein-1 (MCP-1) and interleukin-6 (IL-6) were decreased. Compared with troglitazone, KMF decreased the production of reactive oxygen species (ROS) and nuclear factor-kappaB (NFkappaB) activation. Glucose uptake was stimulated by KMF in differentiated 3T3-L1 adipocytes. Taken together, these results indicate that KMF may exert beneficial effects against diabetes via its ability to regulate adipocyte differentiation and function.

Acute lymphoblastic leukemia (ALL) with t(8;14)(q11.2;q32) in an elderly patient.

Acute lymphoblastic leukemia (ALL) with chromosome aberration t(8;14)(q11.2;q32) mostly affects patients younger than 20 years old. One third of patients with this translocation have been reported to have Down syndrome. This translocation has been reported rarely in patients over the age of 50. Here we report a 71-year-old male ALL patient who carried t(8;14)(q11.2;q32). Fluorescence in situ hybridization (FISH) analysis revealed the involvement of CCAAT enhancer-binding protein delta (CEBPD) gene on chromosome 8, and IgH gene on chromosome 14. This case provides a new aspect for considering this clinical entity.

Ripening-associated ethylene biosynthesis in tomato fruit is autocatalytically and developmentally regulated.

To investigate the regulatory mechanism(s) of ethylene biosynthesis in fruit, transgenic tomatoes with all known LeEIL genes suppressed were produced by RNA interference engineering. The transgenic tomato exhibited ethylene insensitivity phenotypes such as non-ripening and the lack of the triple response and petiole epinasty of seedlings even in the presence of exogenous ethylene. Transgenic fruit exhibited a low but consistent increase in ethylene production beyond 40 days after anthesis (DAA), with limited LeACS2 and LeACS4 expression. 1-Methylcyclopropene (1-MCP), a potent inhibitor of ethylene perception, failed to inhibit the limited increase in ethylene production and expression of the two 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS) genes in the transgenic fruit. These results suggest that ripening-associated ethylene (system 2) in wild-type tomato fruit consists of two parts: a small part regulated by a developmental factor through the ethylene-independent expression of LeACS2 and LeACS4 and a large part regulated by an autocatalytic system due to the ethylene-dependent expression of the same genes. The results further suggest that basal ethylene (system 1) is less likely to be involved in the transition to system 2. Even if the effect of system 1 ethylene is eliminated, fruit can show a small increase in ethylene production due to unknown developmental factors. This increase would be enough for the stimulation of autocatalytic ethylene production, leading to fruit ripening.

[Development of treatment adherence by jellification of itraconazole oral solution].

There have been some reports on the efficacy and tolerability of itraconazole (ITCZ) as prophylaxis for fungal infection after HSCT, and guidelines recommend itraconazole as a standard drug for prophylaxis of fungal infection in HSCT patients. However, it is not uncommon for patients undergoing HSCT to develop anorexia and taste disturbance. There are some cases where the bitter taste of ITCZ oral solution leads to interruption of administration because the patient refuses to take this medicine. Therefore, we investigated the clinical utility and influence on continuing treatment adherence by jellification of ITCZ. Compared with ITCZ oral solution, jellified ITCZ was extremely easy for most patients to take, and it was suggested that jellified ITCZ can make it easier for patients to continue treatment if they have difficulty with administration because of the bitter taste of ITCZ oral solution. Furthermore, it was confirmed that the plasma concentration of ITCZ was suitable for prophylaxis even with jellified ITCZ. This also suggested that the efficacy of ITCZ would be maintained by using jellified formation. For long-term antifungal therapy in patients with a high risk of fungal infection such as those having HSCT, it is very important for successful prophylaxis to maintain good adherence.

Philadelphia chromosome-positive acute myeloid leukemia (Ph + AML) treated with imatinib mesylate (IM): a report with IM plasma concentration and bcr-abl transcripts.

We studied the efficacy and pharmacokinetics of imatinib mesylate (IM) and bcr-abl expression in a Philadelphia chromosome-positive acute myeloid leukemia (Ph + AML) patient, a rare disease with a poor prognosis. Although sufficient IM trough concentrations were maintained, bcr-abl transcripts revealed only one-log reduction with IM monotherapy, suggesting a resistance against IM, and this patient required additional chemotherapy. Despite the resistance against IM at induction therapy, the patient has been in complete molecular response for more than 6 months with IM maintenance monotherapy. Our experience suggests that IM might have a positive role in consolidation and/or maintenance therapy in remission Ph + AML patients.

A peculiar case of acute myeloid leukemia mimicking plasmacytoid dendritic precursor cell leukemia.

Differential diagnosis between plasmacytoid dendritic precursor cell leukemia (pDC leukemia) and acute myeloid leukemia (AML) with monocytic differentiation is difficult due to shared clinicopathological features ; however, such diagnosis is critical because the two leukemias are treated differently. Here we report a peculiar case of AML mimicking pDC leukemia. A 22-year-old man presented with leukocytopenia and bone marrow involvement of atypical plasmacytoid cells with a prominent nucleolus. In spite of positive cytochemical staining for NaF-sensitive naphthyl butyrate esterase, this case was diagnosed as pDC leukemia because the abnormal cells were positive for CD4, CD56, and CD123, and negative for myeloperoxidase and lysozyme. The patient achieved complete remission after 4 courses of combination chemotherapy, but relapsed four months later with leukemic manifestation and skin involvement. The morphology of the leukemia cells became myelomonoblastic, and some were immunohistochemically positive for lysozyme, suggesting AML. Although the patient received allogenic stem cell transplantation twice, he died of progressive disease. This case demonstrates the importance of cytochemical staining for naphthyl butyrate esterase in differential diagnosis between AML and pDC leukemia coexpressing CD4, CD56, and CD123.

Small cell variant of anaplastic large cell lymphoma diagnosed by a novel chromosomal abnormality t(2;5;3)(p23;q35;p21) of bone marrow cells.

Because of the rarity and the morphological variations, small cell variant of anaplastic large cell lymphoma (ALCL) represents a diagnostic challenge. Herein is reported a case of leukemic type of small cell variant of ALCL, in which the diagnosis was established by a cytogenetic analysis. The patient was a 23-year-old woman who presented with fever and leukocytosis with circulatory atypical lymphoid cells. The initial differential diagnosis on bone marrow trephine biopsy sections included viral infection and peripheral T-cell lymphoma unspecified. But a cytogenetic study on bone marrow cells indicated a novel complex translocation, t(2;5;3)(p23;q35;p21), which led to confirmation of anaplastic lymphoma kinase (ALK)-positive pleomorphic small to medium-sized cells scattered in bone marrow cells, on immunohistochemistry. ALK was distributed in both nuclear and cytoplasmic regions of neoplastic cells. The patient achieved complete remission after four courses of combination chemotherapy, and received autologous peripheral stem cell transplantation (auto-PBSCT) after two additional courses of combination chemotherapy, but relapsed 2 months after auto-PBSCT in the bilateral lung. Allogeneic stem cell transplantation led to a second remission. This case demonstrates the diagnostic importance of cytogenetic study for malignant lymphoma involving bone marrow.