[Intelukin-10 expression with immunorreglatory function in the mucosa of patients with ulcerative colitis]. / Expresión de la interleucina (IL-10) con función inmunorreguladora en mucosa de pacientes con colitis ulcerosa crónica idiopática.

BACKGROUND: Interleukin-10 (IL-10) is an important immunoregulatory cytokine that acts on antigen presenting cells by the inhibiting both the synthesis of cytokines, co-stimulatory and HLA class II molecules. OBJECTIVE: To study the gene and protein expression of IL-10 in the mucosa from patients with ulcerative colitis (UC). METHODS: We studied 40 patients with UC and 18 controls without endoscopic evidence of intestinal inflammation. From rectal biopsies was determined the gene expression of IL- 10 by real time polymerase chain reaction (PCR). The detection of the protein in tissue was performed by immunohistochemistry. RESULTS: patients with UC in remission had significantly higher expression of il-10 gene in mucosa compared to the group of patients with active UC (p = 0.01) and the control group (p = 0.05). All patients with active UC had pancolitis, while patients in remission from distal inflammation, 16 had extra-intestinal manifestations and 23 had mild to moderate inflammation with less than one relapse within a year. Patients with UC in remission had significantly higher expression of IL-10 gene in mucosa compared with the group of patients with active UC (p = 0.01) or the control group (p = 0.05). CONCLUSIONS: The expression of IL-10 gene is increased in colonic mucosa from patients with UC in remission, confirming that it is an immunoregulatory cytokine that promotes remission in patients with UC.

RANTES and macrophage inflammatory protein 1 alpha selectively enhance immunoglobulin (IgE) and IgG4 production by human B cells.

We studied the effects of various chemokines including neutrophil-activating peptide 2 (NAP-2), beta-thromboglobulin (beta-TG), platelet factor 4 (PF-4), melanoma growth stimulating activity (GRO), gamma interferon-induced protein (IP-10), regulated on activation, normal T expressed and secreted (RANTES), macrophage inflammatory protein 1 alpha (MIP-1 alpha), MIP-1 beta, and monocyte chemotactic protein 1 (MCP-1) on Immunoglobulin (IgE) and IgG4 production by human B cells. None of these chemokines with or without interleukin (IL-4), anti-CD40 or -CD58 monoclonal antibody (mAb), induced IgE and IgG4 production by B cells from nonatopic donors. However, RANTES and MIP-1 alpha selectively enhanced IgE and IgG4 production induced by IL-4 plus anti-CD40 or -CD58 mAb without affecting production of IgM, IgG1, IgG2, IgG3, IgA1, or IgA2, whereas other chemokines failed to do so. Enhancement of IgE and IgG4 production by RANTES and MIP-1 alpha was specifically blocked by anti-RANTES mAb and anti-MIP-1 alpha antibody (Ab), respectively, whereas anti-IL-5 mAb, anti-IL-6 mAb, anti-IL-10 Ab, anti-IL-13 Ab, and anti-tumor necrosis factor-alpha mAb failed to do so. Purified surface IgE positive (slgE4) and slgG4+ B cells generated either in vitro or in vivo spontaneously produced IgE and IgG4, respectively, whereas sIgE- and sIgG4- B cells failed to do so. RANTES and MIP-1 alpha enhanced spontaneous IgE and IgG4 production in slgE+ and slgG4- B cells, respectively, whereas neither RANTES nor MIP-1 alpha did so in sIgE- or sIgG4- B cells. Purified sIgE4+ and sIgG4+, but not sIgE- or sIgG4- B cells, generated in vitro and in vivo expressed receptors for RANTES and MIP-1 alpha, whereas they failed to express receptors for other chemokines. These findings indicate that RANTES and MIP-1 alpha enhance IgE and IgG4 production by directly stimulating sIgE+ and sIgG4+ B cells.

NADH dehydrogenase deficiency in an apoptosis-resistant mutant isolated from a human HL-60 leukemia cell line.

An apoptosis-resistant mutant (VC-33) was selected from HL-60 by alternating exposure to camptothecin and etoposide. VC-33 cells demonstrated resistance to apoptosis as induced not only by camptothecin and etoposide but by a variety of other agents as well, including 1-beta-D-arabinofuranosylcytosine, hydroxyurea, calcium ionophore (A23187), cycloheximide, and UV irradiation. In an effort to identify the mechanism of such apoptosis resistance, a mRNA differential display analysis was used. Among a total of 12 bands with reduced expression in VC-33 cells, 1 cDNA clone was isolated that was hybridized to the wild-type transcript but not to the VC-33 transcript on Northern blotting. Partial sequence of this gene revealed 98% homology to mitochondrial NADH dehydrogenase subunit 5. When cell growth and intracellular ATP levels under glucose starvation were measured, VC-33 cells were found to be more sensitive than wild-type cells. Thus, NADH dehydrogenase deficiency may contribute, at least in part, to the mechanism of resistance to apoptosis in VC-33 cells.

IgM-mediated B cell apoptosis.

Cross-linking of surface immunoglobulin M (sIgM) on normal mature B cells induces different signaling consequences, including DNA synthesis (positive signaling) and cell cycle arrest and/or death by apoptosis (negative signaling). Presumably, the difference depends on the intensity of sIgM cross-linking: relatively weak cross-linking induces DNA synthesis, moderate cross-linking induces DNA synthesis with cell cycle arrest at the G2/M interphase, and intense cross-linking induces apoptosis. In vivo experiments with transgenic mice have shown that relatively weak cross-linking of sIgM by soluble antigens induces anergy in autoreactive B cells, whereas intense sIgM cross-linking by membrane-bound forms of antigens induces deletion of them. However, it is still unknown whether the different intensities of sIgM cross-linking generate qualitatively different signals responsible for DNA synthesis or cell death or whether they generate qualitatively the same but quantitatively different signals, and the quantitative difference is responsible for the induction of positive or negative signaling. The sIgM-mediated negative signaling presumably plays an important role in the induction and maintenance of B cell tolerance, and sIgD and sIgG also possess the machinery necessary for negative signaling. Negative signaling through sIgM is dependent on tyrosine kinase(s) and Ca2+ influx and is sensitive to cyclosporin A in certain types of B cells but not in all B cells. It has been suggested that there are different intracellular signaling pathways that transduce negative signaling via sIgM, and that activation-induced B cell death by sIgM cross-linking does not necessarily show DNA fragmentation and the morphology of apoptosis. On the other hand, sIgM-mediated B cell death may be inhibited in the presence of appropriate co-stimulators such as IL-4, alpha-, and beta-interferons and CD40-mediated signaling. The CD40-mediated signaling effectively inhibits sIgM-mediated B cell apoptosis in many but not all experimental systems. Although homotypic cell adhesion through the LFA-1/ICAM-1 dependent pathway was shown to be involved in certain types of CD40-mediated inhibition of sIgM-mediated negative signaling, it is still not known how the cytokines and CD40-mediated signaling inhibit sIgM-mediated B cell death. The molecular mechanisms responsible for sIgM-mediated negative signaling and for the inhibitory signaling against sIgM-mediated negative signaling need further elucidation.

IL-4 and prostaglandin E2 inhibit hypomethylation of the 5' regulatory region of IFN-gamma gene during differentiation of naive CD4+ T cells.

We have previously shown that prostaglandin E2 (PGE2) and IL-4 inhibit the priming of IFN-gamma-production during the differentiation of naive CD4+ T cells from human cord blood by different signal-transducing mechanisms. To compare and analyse the molecular mechanisms by which PGE2 and IL-4 inhibit the priming of IFN-gamma production, we investigated the effects of PGE2 and IL-4 on the methylation of the IFN-gamma gene during the in vitro differentiation of naive CD4+ T cells. In human naive CD4+ T cells, which produce primarily IL-2 and a little amount of IFN-gamma, the IFN-gamma gene was methylated. After stimulation via TCR, CD4+ T cells produced IFN-gamma and the CpG dinucleotide contained within the TATA proximal regulatory element of the IFN-gamma gene was partially hypomethylated. Both IL-4 and PGE2 inhibited the hypomethylation of this site and the acquisition of IFN-gamma-producing ability. In contrast to the SnaBI site in the TATA proximal regulatory element, the HpalI site in the first intron of the IFN-gamma gene of the CD4+ T cells from cord blood was completely methylated even after stimulation via TCR. 5-azacytidine restored the IFN-gamma-producing ability of these cells treated with IL-4 and PGE2. These findings suggest that, although the signal transduction that inhibits the priming of IFN-gamma-production is different for each reagent, the protection from hypomethylation of the regulatory region of the IFN-gamma gene is involved in the molecular mechanisms by which these reagents inhibit the priming of IFN-gamma-production during the differentiation of human naive CD4+ T cells.

Vasoactive intestinal peptide enhances immunoglobulin production and growth in human plasma cells via mechanisms that may involve protein kinase C.

The effects of various neuropeptides on human plasma cells were studied. Of the various neuropeptides tested, vasoactive intestinal peptide (VIP) enhanced Ig production and growth in human plasma cell lines, IM-9 and AF-10, and in plasma cells generated in vivo (four out of four patients with plasma cell leukemia) and in vitro. In contrast, other neuropeptides (neuropeptide Y, somatostatin, substance P, peptide YY, neurokinin A, calcitonin gene-related peptide, chole-cystokinin octapeptide, and beta-endorphin) were ineffective. Moreover, VIP-induced enhancement was specifically blocked by VIP receptor antagonist. Among the various cytokines, IL-6, GH, and insulin-like growth factor I (IGF-I) also enhanced Ig production and thymidine uptake in plasma cells. However, VIP-induced enhancement was not mediated by IL-6, GH, or IGF-I because antibodies to these cytokines failed to block VIP-induced enhancement. Phorbol 12,13 dibutyrate enhanced Ig production and thymidine uptake in plasma cells, and the Phorbol 12,13 dibutyrate-induced enhancement was blocked by H7 (a protein kinase C inhibitor) but not by H8 (a protein kinase A inhibitor). Similarly, VIP-induced enhancement was blocked by H7 but not by H8. Collectively, VIP enhances plasma cell responses via mechanisms that may involve protein kinase C.

Genetic polymorphism of the CYP2C subfamily and its effect on the pharmacokinetics of phenytoin in Japanese patients with epilepsy.

OBJECTIVE: To examine the genetic polymorphism of CYP2C9 and CYP2C19 and its effect on the pharmacokinetics of phenytoin among 44 Japanese patients with epilepsy. METHODS: Polymerase chain reaction tests with leukocyte deoxyribonucleic acid were used to detect the mutations for the amino acid substitution (Arg144-->Cys and Ile359-->Leu) in CgammaP2C9 and for the defective allele (m1 and m2) in CgammaP2C19. The pharmacokinetic parameters of phenytoin in individual patients were estimated by means of empirical bayesian analysis, in which the prior information was the population parameters for Japanese patients with epilepsy. RESULTS: Of the 44 patients, none had the CgammaP2C9 mutation for the Cys144 allele, whereas six patients were heterozygous for the wild-type (wt) and Leu359 allele (wt/Leu359) in cgammaP2C9. The maximal elimination rate (Vmax) of phenytoin among patients with heterozygous wt/Leu359 in CgammaP2C9 was 33% lower than that among patients with normal CgammaP2C9. A total of 21 patients were heterozygous for the CgammaP2C19 mutation (wt/m1 or wt/m2), and five patients had the homozygous or heterozygous mutations in CgammaP2C19 (m1/m1 or m1/m2). The Vmax values of phenytoin were slightly decreased (up to 14%) among patients with CgammaP2C19 mutations compared with patients with normal CgammaP2C19. CONCLUSION: The findings indicated that the genetic polymorphisms of CYP2C isozymes play an important role in the pharmacokinetic variability of phenytoin and that the mutation in CYP2C9 proteins (Ile359-->Leu) is a determinant of impaired metabolism of the drug among Japanese persons.

Association of high molecular weight DNA fragmentation with apoptotic or non-apoptotic cell death induced by calcium ionophore.

Calcium ionophore (A23187)-induced high molecular weight (HMW) and internucleosomal DNA fragmentation were investigated in human leukemia cell lines. An apoptosis-sensitive cell line, HL-60, showed HMW, internucleosomal DNA fragmentation and morphological changes of apoptosis by A23187. MOLT-4, which is resistant to apoptosis, exhibited only HMW DNA fragmentation and died of necrosis under the same conditions. Autodigestion experiments suggested the endonucleolytic activity to cause HMW fragmentation in the cytoplasm of both cell lines. The activity was more dependent on Mg2+ than Ca2+ in HL-60, whereas it was Ca(2+)-dependent in MOLT-4. These results suggest that HMW DNA fragmentation is not specific to apoptosis.

Prospective study of mutant frequencies at the hprt and T-cell receptor gene loci in pediatric cancer patients during chemotherapy.

Mutant frequencies (MFs) at the hypoxanthine phosphoribosyl transferase gene and the T-cell receptor (TCR) gene loci were evaluated in nine pediatric cancer patients before and during anticancer chemotherapy. The study population consisted of three patients with Hodgkin's disease, four patients with neuroblastoma, and two patients with Wilms' tumor. Except for one patient with neuroblastoma and one patient with Wilms' tumor, MFs at the hypoxanthine phosphoribosyl transferase locus tended to increase during the early cycles of treatment. The elevation was most striking and persistent in patients with Hodgkin's disease. The clonal relationship was determined in mutant cells derived from Hodgkin's disease patients by TCR-gamma gene rearrangement pattern and showed that the elevation of MFs resulted from increased mutational events rather than from clonal expansion of mutants. An increase in TCR MF was also found during chemotherapy in most patients, but the time of TCR MF elevation was variable among patients. Among the chemotherapeutic agents used in this study, cyclophosphamide was considered to be the most mutagenic. Our present study clearly demonstrates that anticancer chemotherapy can induce mutagenesis in vivo in various pediatric cancer patients.

Tacrolimus and myocardial hypertrophy.

Tacrolimus has been used as an immunosuppressive agent in the transplantation of all solid organs. Tacrolimus-induced hypertrophic cardiomyopathy has been reported to be an unusual but serious complication. To elucidate the effects of tacrolimus on myocardial hypertrophy, we studied the relationship between the blood levels of tacrolimus and cardiac wall thickening. Our findings demonstrated that tacrolimus-induced myocardial hypertrophy correlated with tacrolimus blood levels, and that myocardial hypertrophy induced by tacrolimus was reversible. However, no patients developed clinically significant symptoms related to myocardial hypertrophy.

Living-related liver transplantation and neurological outcome in children with fulminant hepatic failure.

BACKGROUND: Fulminant hepatic failure (FHF) in children is associated with high mortality under medical management. Living-related liver transplantation (LRLT) is an accepted measure to treat the children with end-stage liver disease. Reversibility of hepatic encephalopathy is crucial for the quality of life among the survivors after transplantation. METHODS: A retrospective review was made of the records of children undergoing LRLT at this hospital between May 1992 and November 1996. RESULTS: Eleven children with FHF underwent emergency LRLT. The mean age was 5 years (range, 2 months to 15 years). The indication for transplantation was persistent or worsening hepatic encephalopathy and severe coagulopathy, despite repeated plasma exchanges or exchange transfusions. The cause of FHF was non-A, non-B hepatitis in seven children, hepatitis B in two children, herpes simplex virus hepatitis in one child, and fulminant Wilson's disease with intravascular hemolysis in one child. The grade of hepatic encephalopathy was II in four children, III in two, and IV in five. The actuarial survival rate was 73% after a mean follow-up of 28 months (range, 13-67 months). Short-term neurological morbidity was present in two children with grade IV encephalopathy who also showed brain edema on cranial computed tomography. Eight survivors exhibited no long-term neurological deficit; the mean intelligence or developmental quotient was 97 (range, 86-110) at the end of the follow-up period. CONCLUSIONS: LRLT is an effective option for the treatment of FHF in children. The long-term neurological status is satisfactory among survivors.

Physical interaction with monocytes rescues human mature CD4+ T-cell lines from anti-CD3-induced apoptosis.

Crosslinking of the TcR-CD3 complex with immobilized anti-CD3 antibodies without sufficient co-stimulation induced cell death in human mature CD4+ T-cell lines. In these T cells, DNA fragmentation and morphological characteristics of apoptosis were seen. The anti-CD3-induced apoptosis was inhibited by co-culture with monocytes. The rescue signal provided by monocytes does not need to be present simultaneously with signals mediated by anti-CD3. When T cells were precultured with monocytes for 24 h before anti-CD3 stimulation and then the monocytes were removed from the culture, anti-CD3-induced T-cell apoptosis was also inhibited. To determine whether the monocyte-derived rescue signals were transduced by soluble factors or by direct cell-to-cell interaction with monocytes, we precultured T cells with monocytes separated by a micropore membrane which prevented T cell-monocyte physical interaction but not the diffusion of secreted molecules. In this system, rescue signals could not reach the T cells. To further assess the importance of physical interaction, we precultured T cells with fixed monocytes. T cells could not be rescued from apoptosis under these experimental conditions, either. The results considered collectively suggest that sufficient physical interaction with viable monocytes is important for the rescue of anti-CD3-induced apoptosis of CD4+ T cells.

Hypomethylation of the proximal and intronic regulatory regions of the IFN-gamma gene is not essential for its transcription by naive CD4+ T cells cultured with IL-4.

Recently, long-term preculture with IL-4 or IL-7 has been reported to induce IFN-gamma-producing ability in naive CD4+ T cells without stimulation via TCR. The mechanism of IFN-gamma-transcription in naive CD4+ T cells precultured with IL-4 was analyzed and compared with that in typical Th1 cells by focusing on the TATA proximal and first intronic regulatory regions of the IFN-gamma gene. Both regulatory regions in these IL-4-primed naive CD4+ T cells, which produce a large amount of IFN-gamma upon stimulation with PMA and ionomycin, were completely methylated in contrast to the same hypomethylated regions in Th1 cells. DNase I hypersensitive site analysis suggested that both regulatory regions in IL-4-primed naive CD4+ T cells were not active for IFN-gamma-expression. Moreover, we demonstrated that the composition of transcriptional factors that can bind to the proximal regulatory region is different between IL-4-primed naive CD4+ T cells and Th1 cells. These results indicated that the transcriptional machinery involved in the expression of the IFN-gamma gene by CD4+ T cells varied depending on their modes of differentiation in both the responsive regulatory regions and the specific nuclear factors.

IL-7 induces proliferation, variable cytokine-producing ability and IL-2 responsiveness in naive CD4+ T-cells from human cord blood.

We investigated the effects of IL-7 on the proliferation and acquisition of cytokine-producing ability of naive CD4+ T-cells from human cord blood. Naive CD4+CD45RA+ T-cells from human cord blood expressed CDw127 (IL-7R) at higher levels than adult CD4+ CD45RA+ T-cells and produced IL-2 and a small amount of IFN-gamma upon stimulation with PMA and ionomycin. IL-7 induced IL-2-independent proliferation and both Th1- and Th2-type cytokine-producing abilities in cord blood CD4+CD45RA+ T-cells without stimulation via TCR. These results suggest that this IL-7-induced antigen-independent activation mechanism could contribute to maintaining the clonal size of naive T-cells with the potential to differentiate into either Th1 or Th2 cells at the sites of IL-7-expression.

Constitutive endonuclease to induce high molecular weight or internucleosomal DNA fragmentation in freshly isolated leukemia cells.

Using an autodigestion method, we investigated endogenous endonuclease(s) in leukemia cells freshly obtained from pediatric patients with various types of leukemia. Endonucleolytic activity was found to cause both high molecular weight and internucleosomal DNA fragmentation at a neutral pH in whole cell lysates of all common acute lymphoblastic leukemia (cALL) blasts, which was Mg2+-dependent and Ca2+-independent. Whole lysates from most acute myeloblastic leukemia (AML) cells possessed similar endonuclease activity, but both Mg2+ and Ca2+ were required for the activity. Our results suggest that leukemia cells of different lineages have distinct constitutive endonucleases, which may play a role in the occurrence of apoptosis in these cells.

Role of protein tyrosine phosphorylation in etoposide-induced apoptosis and NF-kappa B activation.

When a human myeloid cell line, U937, was incubated with etoposide (10 micrograms/mL), morphologically apoptotic cells first appeared at 3 hr and increased with time to 50% at 6 hr. Pretreatment of U937 cells for 30 min with a potent tyrosine kinase inhibitor, herbimycin A (10 microM), significantly suppressed the appearance of apoptotic morphological changes. Concomitantly, herbimycin A pretreatment prevented both high molecular weight and internucleosomal DNA fragmentation induced by etoposide. Two major bands at 30 and 66 kDa with enhanced tyrosine phosphorylation inhibited by herbimycin A were detectable after 30 min of incubation with etoposide. In addition, herbimycin A prevented etoposide-induced NF-kappa B activation. The expressions of Bcl-2 and Bax, on the other hand, were not affected by herbimycin A pretreatment. Herbimycin A was also found to inhibit 1-beta-D-arabinofuranosylcytosine-induced apoptotic changes and NF-kappa B activation. These results suggest that activation of tyrosine kinase(s) may play an important role in apoptotic processes induced by a variety of anti-cancer drugs.

Successful bone marrow transplantation from an HLA-identical unrelated donor in a patient with hemophagocytic lymphohistiocytosis.

We report a 3-year-old girl with hemophagocytic lymphohistiocytosis (HLH) who received BMT from an HLA-identical unrelated donor when the disease was active. She had entered remission in response to chemotherapy consisting of etoposide and methylprednisolone. After a relapse, her disease became refractory to chemotherapy, and splenectomy was performed with marginal improvement. She underwent BMT from an HLA-identical unrelated donor, conditioned with CY, TBI and anti-thymocyte globulin (ATG). She has been in complete remission for 18 months since the BMT. This result suggests that BMT from an HLA-identical unrelated donor should be considered for HLH even if the disease is active.

Increase in nitric oxide in the hypoxic-ischemic neonatal rat brain and suppression by 7-nitroindazole and aminoguanidine.

We measured the changes in nitric oxide (NO) metabolites in the brains of neonatal rats with hypoxic-ischemic damage. There were two peaks of NO metabolites in the lesioned side of the cortex without treatment: one during hypoxia and the other during the re-oxygenation period. Prehypoxic treatment with 7-nitroindazole, a selective neuronal NO synthase inhibitor, suppressed both peaks of NO metabolites, whereas prehypoxic treatment with aminoguanidine, a selective inducible NO synthase inhibitor, partially suppressed only the peak in the re-oxygenation period. These data suggest different roles of neuronal and inducible NO synthases in the pathogenesis of hypoxic-ischemic encephalopathy.

Thymidine kinase deficient cells with decreased TTP pools are hypersensitive to DNA alkylating agents.

The effect of mutational loss of thymidine kinase (TK) on the sensitivity to alkylating agents was investigated in promyelocytic, HL-60, and T-lymphoblastoid, Molt-3, human leukemia cell lines. Although both cell lines exhibited approx. 1% residual TK activity, only HL-60 TK deficient cells had a decreased intracellular TTP pool, i.e., 20% of that of the wild-type. When treated with N-methyl-N'-nitronitrosoguanidine or ethyl methanesulfonate, HL-60 TK deficient cells showed significantly increased killing and mutation frequencies at the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) locus relative than did wild-type. Pretreatment of cells with O6-benzylguanine, an inhibitor of O6-alkylguanine-DNA alkyltransferase, partially abolished those differences. Molt-3 wild-type and TK deficient cells had similar cell survivals and HGPRT mutation frequencies following treatment with alkylating agents. These results indicate that TK deficiency, only when a concomitant decrease of TTP pool is detected, plays a pivotal role in the sensitivity to the cytotoxic and mutagenic effects of alkylating agents.

Somatic cell mutation frequency at the HPRT, T-cell antigen receptor and glycophorin A loci in Cockayne syndrome.

Skin fibroblasts of patients with Cockayne syndrome (CS) are hypersensitive to the lethal or mutagenic effect of ultraviolet light, which may cause genetic instability. Up to now, however, no systematic study of in vivo somatic cell mutation in CS cells has been reported. This article describes our investigation of the mutation frequencies (Mfs) at three different loci, i.e. hypoxanthine-guanine phosphoribosyl transferase (HPRT), T-cell antigen receptor (TCR) and glycophorin A (GPA), in six patients with CS. Mfs at the HPRT and TCR loci were found to be within the normal range as determined in age-matched controls. In the GPA locus of two patients, there was a slight increase, but it was much smaller than that reported in other DNA repair deficient syndromes. The frequency of spontaneous HPRT mutation in Epstein-Barr virus transformed B-lymphoblastoid cells derived from CS patients was similar to that in cells from normal children. The molecular characterization of the representative HPRT mutant T cell clones from CS patients did not show any structural alterations. These results may explain, at least in part, why CS is not associated with predisposition to cancer.