Role of interleukin-8 and growth-regulated oncogene-alpha in the chemotactic migration of all-trans retinoic acid-treated promyelocytic leukemic cells toward alveolar epithelial cells.

OBJECTIVE: Although all-trans retinoic acid (ATRA) can treat acute promyelocytic leukemia (APL), it also causes retinoic acid syndrome with presentations similar to acute respiratory distress syndrome. We investigated the role of interleukin (IL)-8 and growth-regulated oncogene (GRO)-alpha in the chemotactic transmigration of ATRA-treated NB4 (ATRA-NB4) APL cells toward A549 alveolar epithelial cells. DESIGN: An in vitro human cell culture study. SETTING: University hospital research laboratories. SUBJECTS: NB4 and A549 cells. INTERVENTIONS: NB4 and A549 cells were separately cultured with ATRA and/or dexamethasone for 1-3 days. NB4 or ATRA-NB4 cells were then placed in an upper insert and co-incubated with A549 cells or their conditioned medium located in a lower plate. MEASUREMENTS AND MAIN RESULTS: ATRA stimulated NB4 cells to transmigrate toward the A549 cells in a time- and dose-dependent manner. Replacement of A459 condition medium by its original medium abrogated this transmigration. Only A549 cells constitutively secreted GRO-alpha, and both A549 and NB4 cells constitutively secreted IL-8, which was enhanced by ATRA. Exogenous administration of IL-8 or GRO-alpha also promoted the ATRA-NB4 transmigration. The binding assay demonstrated that ATRA-NB4 cells bound IL-8, but not GRO-alpha, more avidly. Pretreatment with antibodies directed against IL-8 and GRO-alpha receptors reduced ATRA-NB4 transmigration by about 60%. Dexamethasone did not suppress their IL-8 secretion and transmigration in ATRA-NB4 cells, but when applied to A549 cells, IL-8 secretion was suppressed but not GRO-alpha secretion, and there was attenuation of ATRA-NB4 transmigration. CONCLUSIONS: IL-8 and GRO-alpha secreted from alveolar epithelial cells play an important role in the cell-cell interaction involved in the chemotactic transmigration of ATRA-treated APL cells toward alveolar epithelial cells.

Effect of ingestion of cow's milk protein hydrolysate formulas on alpha-casein-specific immunoglobulin E and G1 antibody responses in naïve and sensitized mice.

OBJECTIVES: Cow's milk protein hydrolysate formulas are widely used for genetically predisposed atopic infants. Whether hydrolysate formulas can induce oral tolerance to alpha-casein was studied for the first time in naive and sensitized mice. METHODS: Using immunoblotting, residual antigenicity to alpha-casein was examined for in animals fed hydrolysate formulas. Naïve mice fed hydrolysate formulas for 1 to 4 weeks were later sensitized with alpha-casein. Another group of mice sensitized first with alpha-casein were then fed hydrolysate formulas continually for 12 weeks. RESULTS: Oral tolerance measured by immunoglobulin (Ig)E and IgG1 antibody responses to alpha-casein was induced in naïve mice fed NAN for 1 week or NAN-HA for 4 weeks. IgE responses to alpha-casein were suppressed in mice fed NAN-HA for 1 week or Neoangelac FL for 4 weeks. In contrast, mice fed Alfare, Pepti-Junior, or Pregestimil for 1 to 4 weeks did not develop tolerance to alpha-casein. Antibody responses to alpha-casein were not significantly suppressed in sensitized mice fed NAN or hydrolysate formulas for 12 weeks. CONCLUSIONS: Primary IgE responses to alpha-casein are readily suppressed in naïve mice first fed cow's milk formula or partially hydrolyzed formula for 1 week. Conversely, ongoing IgE, IgG1, and IgG antibody responses to alpha-casein are poorly suppressed in previously sensitized mice even after prolonged feeding of cow's milk formula or hydrolysate formulas.

Increased seroprevalence of human herpesvirus 8 in patients with hematological disorders.

Human herpesvirus 8 (HHV8) has been consistently linked to Kaposi's sarcoma and many hematological diseases such as pleural effusion lymphoma, multicentric Castleman's disease, some lymphoproliferative diseases and posttransplantation bone marrow failure. However, whether patients with hematological disorders are at a higher risk of HHV8 infection has not been determined. In this study, indirect immunofluorescence was used to detect antibodies against lytic antigens of HHV8 in 265 patients with hematological disorders. Our data showed that 24.5% of patients (65/265) were seropositive for HHV8 IgG antibody, which was significantly higher than in our general population (p < 0.001). A significantly higher seropositive rate can be found in patients with lymphoma, leukemia, autoimmune cytopenias and myeloproliferative disorders, but not in patients with myeloma or aplastic anemia. No difference in the seropositive rate is associated with gender or age. We conclude that some patients with hematological disorders are at a higher risk of HHV8 infection.

Detection of bcr-abl gene expression at a low level in blood cells of some patients with essential thrombocythemia.

The major bcr-abl fusion gene is seen as a major marker of chronic myeloid leukemia (CML). However, whether the bcr-abl transcript can be detected in patients with essential thrombocythemia (ET) is still a matter of controversy. We detected the messenger RNA expression of the bcr-abl gene using reverse transcription-polymerase chain reaction in peripheral-blood leukocytes (PBLs) from 63 patients with myeloproliferative disorders (including CML, ET, and polycythemia vera [PV]) and 51 normal, healthy volunteers. The bcr-abl transcript was detected in 4 of the 30 ET patients (13.3%), 17 of the 17 CML patients (100%), none of the 16 PV patients (0%), and 1 of the 51 normal subjects (1.9%). Compared with the normal controls, ET patients have a greater tendency to express the bcr-abl transcript in PBLs (P=.06, Fisher's exact test). Further semiquantitative analysis showed that the intensity of bcr-abl transcript expression in 4 ET patients and a normal individual was 10(3) to 10(4) times less than that in the CML patients. We conclude that the bcr-abl transcript can be detected in the PBLs of Philadelphia chromosome (Ph)-negative ET patients but that the level of expression is markedly less than that in CML patients. The clinical significance of this finding merits further investigation.

Moscatilin from the orchid Dendrobrium loddigesii is a potential anticancer agent.

The Dendrobrium species have been commonly used in traditional Chinese medicine as a tonic to nourish the stomach, replenish body fluid, and reduce fever. However, their application as possible therapeutic agents for the treatment of cancers has not been examined. In this study, we want to examine the efficacy of using moscatilin, a natural antiplatelet agent extracted from the stems of Dendrobrium loddigesii, as an anticancer agent. Our results have shown that moscatilin exerts potent cytotoxic effect against cancer cell lines derived from different tissue origins, including those from the placenta, stomach, and lung, but not those from the liver. In addition, we have found that the mechanism of action of moscatilin may be related to its ability to induce a G2 phase arrest in responsive cells. However, unlike some G2 arresting agents, moscatilin has no detectable inhibitory effect on cyclin B-cdc-2 kinase activity. Thus, the precise nature of its cytotoxic mechanism remains to be determined. Our results in this study imply that moscatilin is potentially efficacious for chemoprevention and/or chemotherapy against some types of cancer.

Parvovirus B19 infection in Taiwanese patients with hematological disorders.

Human parvovirus B19 has a strong tissue tropism for erythroid progenitor cells and is a causative agent for anemia. However, it remains unclear whether patients with hematological disorders are at a higher risk of B19 infection. In the present study, we evaluated the prevalence of B19 infection in 278 patients with hematological disorders by indirect antibody capture enzyme-linked immunosorbent assay. Virus inoculation into cell culture (of TF-6, WRL-68, and HL-60) was carried out using serum from patients with positive IgM anti-B19 and was then examined by nested polymerase chain reaction, dot-blot analysis, and sequence analysis. Our data demonstrated that the total seropositive rates of either IgG or IgM were 71.9%. The seropositive rates increase significantly with age (P < 0.001). After adjustment for age, the seropositive rate was significantly higher in our patients than in the general population with standardized rate ratio of 1.56 (95% CI = 1.43-1.68). No significant difference was found among different disease subgroups (P = 0.311). Nine patients (3.2%) had active B19 infection with positive IgM antibody, with four diagnosed as having idiopathic thrombocytopenic purpura (ITP). Viremia of B19 virus could be detected in eight of nine patients, including three patients in serum only, three patients in bone marrow only, and two patients in both serum and bone marrow. We conclude that patients with hematological disease have higher seropositive rates for B19 than occur in normal controls and that study of occult parvovirus B19 infection is recommended in patients with hematological disease.

Garcinone E, a xanthone derivative, has potent cytotoxic effect against hepatocellular carcinoma cell lines.

Treatment of hepatocellular carcinomas (HCCs) with chemotherapy has generally been disappointing and it is most desirable to have more effective new drugs. We extracted and purified 6 xanthone compounds from the rinds (peel) of the fruits of Garcinia mangostana L., using partitioned chromatography and then tested the cytotoxic effects of these compounds on a panel of 14 different human cancer cell lines including 6 hepatoma cell lines, based on the MTT method. Several commonly used chemotherapeutic agents were included in the assay to determine the relative potency of the potential new drugs. Our results have shown that one of the xanthone derivatives which could be identified as garcinone E has potent cytotoxic effect on all HCC cell lines as well as on the other gastric and lung cancer cell lines included in the screen. We suggest that garcinone E may be potentially useful for the treatment of certain types of cancer.

Circulating levels of thrombopoietic and inflammatory cytokines in patients with acute myeloblastic leukemia and myelodysplastic syndrome.

BACKGROUND: The regulation of megakaryocytopoiesis and thrombopoiesis appears to be under the control of an array of hematopoietic growth factors. The regulatory mechanism of endogenous cytokines in circulating platelet counts of thrombocytopenic patients with acute myeloblastic leukemia (AML) and myelodysplastic syndrome (MDS) is still not clear. METHODS: We measured the serum levels of both thrombopoietic and inflammatory cytokines in peripheral blood and bone marrow samples collected from 52 patients with either AML or MDS along with 35 normal control samples. The levels of thrombopoietin (TPO), interleukin (IL)-11, IL-6, IL-8 and stem cell factor (SCF) were determined by ELISA. RESULTS: Platelet counts in the AML/MDS patients during initial diagnosis, chemotherapy and complete remission were 71.2 +/- 11.6, 47.2 +/- 6.1 and 181.4 +/- 26.3 x10(9)/l, respectively. The median value of TPO in AML/MDS patients during diagnosis was 150.6 pg/ml and increased significantly during chemotherapy (median: 828 pg/ml; p < 0.05) but then decreased following complete remission (median: 221.4 pg/ml). However, these levels were all significantly higher in patients than in normal subjects (p < 0.05, p < 0.05 and p < 0.05; respectively), and no significant change was noted in the levels of IL-11 and SCF during treatment of patients or in normal controls. The level of IL-6 was not detectable in normal serum samples but was markedly increased in the AML/MDS patients (median level during diagnosis: 6.7 pg/ml; chemotherapy: 25 pg/ml; complete remission: 7 pg/ml). The level of IL-8 in patients with AML and MDS was markedly elevated during diagnosis (median: 27.5 pg/ml; range: 0-1,587 pg/ml), but decreased to the level of the normal controls when patients were under chemotherapy or in complete remission. CONCLUSIONS: The endogenous levels of TPO, IL-6 and IL-8 are elevated in the thrombocytopenic patients with AML and MDS. Our results are consistent with previous mechanistic studies and suggest that TPO and IL-6 may be active mediators of platelet production.

Bone marrow samples from patients with aplastic anemia are not infected with parvovirus B19 and Mycobacterium tuberculosis.

The majority of patients with aplastic anemia (AA) have an idiopathic form of the disease. The aim of this study was to detect the presence of parvovirus B19 DNA and Mycobacterium tuberculosis (MTB) DNA by nested polymerase chain reaction (N-PCR) assays in the bone marrow biopsy samples from 30 patients with idiopathic AA. Serologic assays for parvovirus B19 were based on indirect antibody capture enzyme-linked immunosorbent assay. Our results indicate that neither parvovirus B19 DNA nor MTB DNA could be demonstrated in any of the bone marrow samples by N-PCR. Moreover, IgM antibody against parvovirus B19 also was undetectable in the serum samples of 17 patients. Thus, our results suggest that parvovirus B19 and MTB are not associated with AA and, consequently, do not have a role in the pathogenesis of this disease.