Model systems in heterogeneous catalysis: towards the design and understanding of structure and electronic properties.

We discuss in this paper two case studies related to nano-particle catalyst systems. One concerns a model system for the Cr/SiO2 Phillips catalyst for ethylene polymerization and here we present XPS data to complement the previously published TPD, IRAS and reactivity studies to elucidate the electronic structure of the system in some detail. The second case study provides additional information on Au nano-particles supported on ultrathin MgO(100)/Ag(100) films where we had observed a specific activity of the particle's rim at the metal-oxide interface with respect to CO2 activation and oxalate formation, obviously connected to electron transfer through the MgO film from the metal substrate underneath. Here we present XPS and Auger data, which allows detailed analysis of the observed chemical shifts. This analysis corroborates previous findings deduced via STM.

Pathotyping of Escherichia coli isolated from community toilet wastewater and stored drinking water in a slum in Bangladesh.

This study investigated the occurrence of Escherichia coli pathotypes in sanitary wastewater and drinking water in a Bangladeshi urban slum and the potential associations between these sources. We examined 621 E. coli isolates from sanitary wastewater and stored drinking water by multiplex PCR and dual-index sequencing, classifying them into eight pathotypes based on 14 virulence genes and additionally evaluating the possession of the human-specific E. coli genetic biomarker H8. The proportions of pathogenic E. coli were significantly different (P < 0·001) between wastewater (18·6%) and drinking water (1·7%). StIb-positive enterotoxigenic E. coli (ETEC) were predominant in wastewater, indicating that people in the site carried ETEC. In contrast, no ETEC was present in drinking water and the proportion of H8-positive isolates was significantly smaller (7·8%) than that in wastewater (16·3%) (P = 0·001). Our findings indicate that sanitary wastewater from the slum was heavily contaminated with pathogenic E. coli, posing a great health risk. Furthermore, E. coli contamination of drinking water could be derived from not only human but also other sources. SIGNIFICANCE AND IMPACT OF THE STUDY: Sanitary wastewater from an urban slum was heavily contaminated with pathogenic Escherichia coli. It is worth noting a great health risk of accidental exposure to pathogenically contaminated wastewater improperly discharged in and around urban slums. The distinct difference in pathotypes between wastewater and drinking water and the significantly smaller positive proportion of the human-specific E. coli genetic biomarker (H8) in drinking water indicate that drinking water contamination could be derived from not only human but also other sources. This highlights that pathotyping in association with the H8 marker provides an indication of pathogen contamination sources of environmental transmission media.

L1503R is a member of group I mutation and has dominant-negative effect on secretion of full-length VWF multimers: an analysis of two patients with type 2A von Willebrand disease.

Type 2A von Willebrand disease (VWD) is characterized by decreased platelet-dependent function of von Willebrand factor (VWF); this in turn is associated with an absence of high-molecular-weight multimers. Sequence analysis of the VWF gene from two unrelated type 2A VWD patients showed an identical, novel, heterozygous T-->G transversion at nucleotide 4508, resulting in the substitution of L1503R in the VWF A2 domain. This substitution, which was not found in 60 unrelated normal individuals, was introduced into a full-length VWF cDNA and subsequently expressed in 293T cells. Only trace amount of the mutant VWF protein was secreted but most of the same was retained in 293T cells. Co-transfection experiment of both wild-type and mutant plasmids indicated the dominant-negative mechanism of disease development; as more of mutant DNA was transfected, VWF secretion was impaired in the media, whereas more of VWF was stored in the cell lysates. Molecular dynamic simulations of structural changes induced by L1503R indicated that the mean value of all-atom root-mean-squared-deviation was shifted from those with wild type or another mutation L1503Q that has been reported to be a group II mutation, which is susceptible to ADAMTS13 proteolysis. Protein instability of L1503R may be responsible for its intracellular retention and perhaps the larger VWF multimers, containing more mutant VWF subunits, are likely to be mal-processed and retained within the cell.

Skewed X chromosome inactivation in fraternal female twins results in moderately severe and mild haemophilia B.

Female carriers of haemophilia B are usually asymptomatic; however, the disease resulting from different pathophysiological mechanisms has rarely been documented in females. In this study, we investigated the mechanisms responsible for haemophilia B in fraternal female twins. We sequenced the factor IX gene (F9) of the propositus, her father, a severe haemophilia B patient and the other family members. X chromosome inactivation was assessed by the methylation-sensitive HpaII-PCR assay using X-linked polymorphisms in human phosphoglycerate kinase 1 gene (PGK1) and glutamate receptor ionotropic AMPA 3 gene (GRIA3). The twins were found to be heterozygotes with a nonsense mutation (p.Arg384X) inherited from their father. The propositus, more severely affected twin, exhibited a significantly higher percentage of inactivation in the maternally derived X chromosome carrying a normal F9. The other twin also showed a skewed maternal X inactivation, resulting in a patient with mild haemophilia B. Thus, the degree of skewing of maternal X inactivation is closely correlated with the coagulation parameters and the clinical phenotypes of the twins. Furthermore, we identified a crossing-over in the Xq25-26 region of the maternal X chromosome of the more severely affected twin. This crossing-over was absent in the other twin, consistent with their fraternal state. Differently skewed X inactivation in the fraternal female twins might cause moderately severe and mild haemophilia B phenotypes, respectively.

Comparison of topoisomerase I inhibition, DNA damage, and cytotoxicity of camptothecin derivatives presently in clinical trials.

BACKGROUND: Camptothecins belong to a group of anticancer agents with a unique mechanism of action: poisoning of eukaryotic DNA topoisomerase I. Two camptothecin derivatives, topotecan (TPT) and CPT-11, are in clinical trials and their chemotherapeutic efficacy appears promising. PURPOSE: Our aim was to compare simultaneously the molecular and cellular pharmacology of the various camptothecin derivatives that are presently in clinical trials. METHODS: Cytotoxicity of drugs toward human colon carcinoma HT-29 cells was determined by colony-forming assays. DNA single-strand breaks (SSB) were measured by alkaline elution. Drug potency to induce topoisomerase 1-mediated DNA cleavage and the sequence selectivity of the breaks were determined by sequencing gel autoradiography. RESULTS: SN-38 and CPT were more cytotoxic than 9-AC and TPT, and CPT-11 was almost inactive toward HT-29 cells. IC50 values were 8.8 nM for SN-38, 10 nM for CPT, 19 nM for 9-AC, 33 nM for TPT, and greater than 100 nM for CPT-11. In drug-induced DNA damage measured by alkaline elution drug concentrations producing 1000-rad-equivalents (C1000), values were 0.037 microM for SN-38, 0.051 microM for CPT, 0.085 microM for 9-AC, 0.28 microM for TPT, and greater than 1 microM for CPT-11. SN-38 remained the most potent compound in isolated nuclei, and CPT-11 was still inactive. The potency ranking was the same as in whole cells, and the C1000 values were 0.0025 microM for SN-38, 0.012 microM for CPT, 0.021 microM for 9-AC, 0.44 microM for TPT, and greater than 0.1 microM for CPT-11. Potency difference between SN-38 and the other compounds was greater in isolated nuclei than in whole cells. CONCLUSIONS: Kinetics of the reversal of drug-induced SSB in isolated nuclei suggest that dissociation of SN-38 from cleavable complexes is much slower than that of CPT. Cleavage patterns of CPT and 9-AC were similar but differed from those of TPT and SN-38. Although in vitro analyses do not necessarily reflect chemotherapeutic efficacy, this study found that SN-38 is the most potent compound and that 9-AC and TPT are less active than CPT in this system. The effect of CPT-11 is minimal. Therefore, the clinical activity of CPT-11 may strongly depend on its hydrolysis to SN-38. Differences in DNA sequence selectivity and the stability of cleavable complexes induced by the drugs may also contribute to differences among CPT derivatives.

Effect of lymphokine-activated killer cell fraction on the development of human hematopoietic progenitor cells.

Lymphokine-activated killer (LAK) cells from cultures of human peripheral blood mononuclear cells with recombinant interleukin-2 (rIL-2) have been clinically used in adoptive immunotherapy for cancer patients. To study their influence on human hematopoiesis, the LAK cell fraction was cocultured with marrow nonphagocytic cells from normal subjects in an assay system of hematopoietic progenitors. The fraction suppressed colony growth from relatively mature erythroid progenitors in a dose-dependent manner. Although unactivated cells, which were produced without IL-2, augmented the growth of early erythroid progenitors, the LAK cell fraction did not. This fraction suppressed colony growth from mature granulocyte-macrophage progenitors (day 7 CFU-GM) especially with an 18-h preincubation prior to coculture. It also suppressed both immature granulocyte-macrophage progenitors (day 14 CFU-GM) and multipotential hematopoietic progenitors. The suppressive effects were observed on colony growth from autologous marrow cells as well as allogeneic marrow cells. The suppression of day 7 CFU-GM colony growth by supernatants due to preincubation with marrow cells and the LAK cell fraction suggested that the humoral factor contributes to the suppression by the LAK cell fraction. These data suggest that the LAK cell fraction suppresses the development of human hematopoietic progenitor cells.

Local treatment with antithrombotic drugs can prevent thrombus formation: an angioscopic and angiographic study.

OBJECTIVES: This study was designed to evaluate the efficacy of local versus systemic treatment of thrombosis with various antithrombotic drugs. BACKGROUND: Local use of low dose antithrombotic drugs has been proposed as being effective and safe. METHODS: Heparin (30 U/kg), an antithrombin agent (argatroban, 0.05 mg/kg body weight) or a defibrinogenating drug (batroxobin, 0.05 U/kg) was locally infused into one side of the canine iliac artery after injury by balloon inflation. The other side was injured as a control. The efficacy of systemic delivery of high dose (heparin [300 U/kg] and argatroban [0.5 mg/kg]) and low dose drugs was also assessed. RESULTS: Sixty minutes after local treatment in 22 dogs, no thrombotic stenosis was observed by angiography in locally treated arteries (p < 0.005 vs. mean thrombotic stenosis of 27% in control segments for heparin, 25.3% in control segments for argatroban and 32% in control segments for batroxobin). Angioscopy demonstrated the same trend. In locally treated arteries, thrombus weight was significantly lower in the treated than control side. In the systemic high dose group (n = 10), angiographic thrombotic stenosis was < 5% after high dose drug delivery (p < 0.05 vs. control segments, 37.4% for heparin, 43% for argatroban). In another 10 dogs, low dose systemic delivery was not effective in inhibiting thrombus formation. Activated partial thromboplastin time and fibrinogen levels did not change with local treatment. CONCLUSIONS: Compared with systemic administration of antithrombotic drugs, local treatment is a safer and more effective method of preventing thrombosis.

Adult respiratory distress syndrome-like disorders after allogeneic bone marrow transplantation.

BACKGROUND: Adult respiratory distress syndrome-like respiratory disorders are a serious, but uncommon, complication of bone marrow transplantation. METHODS: We measured various cytokines in 2 patients with respiratory disorders and 11 patients without respiratory problems after allogeneic bone marrow transplantation. RESULTS: The patients with respiratory disorders had elevated levels of interferon-gamma and interleukin-2 in the aplastic phase, and elevation of tumor necrosis factor-alpha, intercellular adhesion molecule-1, and interleukin-8 at the time of leukocyte recovery. Both patients with respiratory disorders developed fever during the aplastic phase, whereas none of the patients without fever had respiratory disorders. Among patients who had fever during the aplastic phase but no respiratory disorders, there was no elevation of cytokines from the aplastic phase to the recovery phase. CONCLUSIONS: Respiratory disorders may occur after bone marrow transplantation when an inflammatory response during the aplastic phase stimulates cytokines that cause vascular endothelial damage and increases the levels of chemokines and adhesive molecules along with elevation of the leukocyte count.

Treatment of intestinal graft-versus-host disease using betamethasone enemas.

Intestinal graft-versus-host disease (GVHD) can readily easily induce generalized metabolic disturbance that influences morbidity and mortality after allogeneic bone marrow transplantation. Although adding a new drug or increasing the doses of immunosuppressive agents will probably be effective for controlling intestinal GVHD, the systemic side effects of such therapy cannot be ignored. In this study, we used betamethasone retention enemas as a local treatment for eight patients with refractory and/or severe intestinal GVHD. Six of the eight patients showed improvement of diarrhea and/or abdominal pain, with a reduction in the stage of GVHD. When treatment with betamethasone enemas was continued for 10 to 27 days in the 6 responding patients, no severe toxicity was observed. One patient failed to respond to treatment and another could not tolerate the enemas. Despite some uncertainty regarding the indications and duration of treatment, betamethasone enemas seem to be a potential alternative method for the management of intestinal GVHD.

Proliferative markers in gastric carcinoma and organoid differentiation.

The present study was undertaken to elucidate the relationship between the distribution of potentially proliferative tumor cells and the organoid differentiation of tumor cells in gastric carcinomas. One hundred four specimens of surgically removed human gastric carcinomas, including 68 and 36 specimens of early and advanced carcinomas, respectively, were studied by using a battery of histochemical techniques. Serial 3-microns thick paraffin sections were stained by galactose oxidase-cold thionine Schiff-paradoxical concanavalin A staining (GOCTS-PCS), or were immunostained for pepsinogen types I and II, lysozyme, and proliferating cell nuclear antigen (PCNA). In addition, to identify proliferative tumor cells parts of fresh carcinoma tissues were incubated in a solution containing bromodeoxyuridine (BrdU), embedded in paraffin, and immunostained for BrdU. The results indicated that in intramucosal carcinoma tissues showing organoid differentiation the proliferative tumor cells were located predominantly between the covering epithelial cell type tumor cells and the glandular mucous cell type tumor cells, and the disturbance in the distribution of proliferative cells coincided with the submucosal invasion.

Predicting the severity of intestinal graft-versus-host disease from leukotriene B4 levels after bone marrow transplantation.

Intestinal graft-versus-host disease (GVHD) produces clinical manifestations and histological changes resembling those of ulcerative colitis and has been treated with drugs which are used for ulcerative colitis. These two conditions also resemble each other with respect to changes of cytokines. Accordingly, we investigated whether the level of leukotriene B4, a risk factor for ulcerative colitis, was also a risk factor or prognostic indicator for intestinal GVHD. The pre-conditioning leukotriene B4 level was significantly related to the grade of intestinal GVHD in 42 patients (P < 0.01). Compared with patients who did not develop severe intestinal GVHD after bone marrow transplantation, those who did had significantly higher interleukin-2 and interferon-gamma levels during the aplastic phase (P <0.01), followed by higher tumor necrosis factor-alpha levels during the recovery phase (P < 0.0001), with significant elevation of tumor necrosis factor-alpha and interferon-gamma occurring in association with exacerbations of intestinal GVHD (P < 0.001). These findings suggest a similarity between the pathogenesis of ulcerative colitis and intestinal GVHD and raise the possibility that leukotriene B4 may be a useful prognostic indicator for intestinal GVHD.

Influence of Helicobacter pylori on platelets after bone marrow transplantation from unrelated donors.

This study was performed to clarify the influence of Helicobacter pylori on the platelet count in patients undergoing bone marrow transplantation (BMT) from unrelated donors. Of 23 consecutive patients undergoing BMT from unrelated donors, the H. pylori antibody test did not change from before conditioning until recovery of the platelet count in 15 patients. These patients were classified into H. pylori antibody-positive (n=8) and -negative (n=7) groups. In the H. pylori antibody-positive group, the platelet count exceeded 20 x 10(9)/l significantly faster after BMT, than in the H. pylori antibody-negative group. When myelosuppression was most severe, the interleukin-6 (IL-6) level was significantly higher in the positive group than in the negative group (67.0+/-10.6 vs 9.9+/-2.4 pg/ml, P<0.05). In addition, the thrombopoietin level was significantly lower in the positive group than in the negative (510.1+/-313.9 vs 3209.1+/-2006.7 pg/ml, P<0.01). These data suggest that H. pylori infection accelerates recovery of the platelet count after BMT from unrelated donors, possibly by stimulating IL-6 production.

Prognostic value of cyclic GMP in patients undergoing allogeneic bone marrow transplantation after conditioning with total body irradiation.

This study was performed to investigate whether measurement of cyclic GMP (cGMP), a marker for nitric oxide production, before and after allogeneic bone marrow transplantation (BMT) with total body irradiation (TBI) conditioning was of prognostic value. cGMP levels were monitored in 23 consecutive patients who received TBI as conditioning for BMT, and were compared with the outcome. cGMP became positive during the aplastic phase after BMT in 12 patients. In nine of these 12 patients, cGMP level decreased during the recovery phase. Eight of the nine patients survived, one dying after relapse. In three other patients, the cGMP level continued to increase even during the recovery phase and they died of severe complications. cGMP became positive on day 0 of BMT and during the leukocyte recovery phase after BMT in two and seven of the 23 patients, respectively. Subsequently, all patients died of severe complications. The two patients who were negative for cGMP both before and after BMT survived without complications. These results suggest that monitoring cGMP from early after BMT may be useful for predicting outcome and that it may be a useful prognostic marker.

The levels of soluble P-selectin, von Willebrand factor and thrombomodulin in patients with neurological complications after allogeneic bone marrow transplantation.

We encountered two patients with uncommon neurological manifestations after allogeneic bone marrow transplantation (BMT), which occurred with rapid elevation of the leukocyte count at engraftment. Both patients then developed severe acute graft-versus-host disease (GVHD). To investigate the pathogenesis, we measured the levels of soluble P-selectin, von Willebrand factor (vWF) and thrombomodulin (TM), which reflect endothelial damage. The P-selectin, vWF and TM levels in the patients with (n=2) and without (n=5) neurotoxicity were, respectively, 168.5+/-52.5 ng/ml vs 27.7+/-3.9 ng/ml, 6.7+/-0.15 FU/ml vs 3.42+/-0.41 FU/ml and 459+/-37% vs 189.4+/-32.4% (mean+/-s.d.). All three parameters were much higher in the patients with neurological complications. These results suggest that neurotoxicity after BMT may be related to endothelial damage.

Urinary trypsin inhibitor concentration can predict the immunological insult of chemotherapy and complications after bone marrow transplantation.

Urinary trypsin inhibitor has attracted attention as an index of the systemic inflammatory response syndrome. In this study, the urine concentration of trypsin inhibitor was measured to compare the immunological insult of conventional chemotherapy and conditioning chemotherapy for bone marrow transplantation. We also investigated whether urinary trypsin inhibitor was a useful index of the complications and outcome of bone marrow transplantation. Urinary trypsin inhibitor concentration was determined before chemotherapy, on the day after finishing chemotherapy (day 0 of transplantation), and during recovery of the white cell count, in 17 patients (seven receiving conventional chemotherapy and 10 receiving conditioning for bone marrow transplantation). Urinary trypsin inhibitor concentrations were significantly higher after conditioning for bone marrow transplantation than after conventional chemotherapy (P < 0.001), indicating that conditioning was more invasive. After bone marrow transplantation, the incidence of severe complications and the mortality rate were higher in patients whose urinary trypsin inhibitor concentrations rose during recovery of the white cell count. Comparison of urinary trypsin inhibitor concentrations suggested that conditioning for bone marrow transplantation was more invasive than conventional chemotherapy. This study also suggested that the urine concentration of trypsin inhibitor could be useful for predicting the risk of complications and outcome of bone marrow transplantation.

Increased hepatocyte growth factor in serum in acute graft-versus-host disease.

Hepatocyte growth factor (HGF) was reported to be effective in preventing acute graft-versus-host disease (GVHD) in a murine model. We examined serum HGF concentrations in 38 patients receiving allogeneic bone marrow transplants, and investigated the relationship of serum HGF concentrations to severity of acute GVHD. More HGF was present in sera from patients with than without acute GVHD. Serum HGF correlated significantly with grade of acute GVHD. Furthermore, serum HGF correlated with serum concentrations of C-reactive protein, gamma-glutamyltranspeptidase (GTP), and aspartate aminotransferase (AST). Serum concentrations of HGF in transplanted patients without GVHD were consistently low, while those in patients with acute GVHD increased with exacerbation. We conclude that HGF was produced during induction of the GVH reaction, and probably increased as a physiological response.

Complications after bone marrow transplantation are manifestations of systemic inflammatory response syndrome.

Bone marrow transplantation has been established as a useful treatment for various hematological disorders and is now performed widely, but the mortality rate is still high due to various complications. A clear therapeutic policy for such complications has not yet been established because of their complex nature. We investigated whether the major complications occurring after bone marrow transplantation could be classified as aspects of the systemic inflammatory response syndrome. Subjects were 10 patients who developed severe complications after bone marrow transplantation (graft-versus-host disease, thrombotic microangiopathy, respiratory disorders, and cytomegalovirus interstitial pneumonitis) and 16 patients without complications. Their symptoms, serum cytokines, and factors related to vascular endothelial damage were compared before and after transplantation. Whereas all 10 patients who developed complications had fever in the aplastic phase after transplantation, 15 of the 16 patients without complications remained afebrile (P < 0.001, t-test). When compared with the patients who did not develop complications, the patients with complications also showed significantly higher cytokine levels during the recovery phase after transplantation (P < 0.0001, t-test). Thus, the patients with complications developed fever in the aplastic phase and showed an increase of cytokines during the recovery phase, which triggered the occurrence of vascular endothelial damage shown by factors such as the thrombomodulin and plasminogen activator inhibitor type 1. This sequence of events corresponds with that occurring during systemic inflammatory response syndrome, so many of the complications of bone marrow transplantation can be considered as manifestations of this syndrome.

Evaluation of CMV/human herpes virus-6 positivity in bronchoalveolar lavage fluids as early detection of acute GVHD following BMT: evidence of a significant relationship.

We evaluated the relationship between CMV and human herpes virus-6 (HHV-6) reactivation and the incidence of grades 2 to 4 acute GVHD post BMT. Bronchoalveolar lavage fluid (BALF) samples extracted from 54 BMT recipients on post-BMT day 35 were analyzed by PCR for detection of CMV DNA, HHV-6 DNA and CMV plus HHV-6 DNA. CMV DNA was detected in 26 patients and 13 (50%) developed grades 2 to 4 acute GVHD. Of the 28 who were CMV negative, only six (21.4%) developed grades 2 to 4 acute GVHD. HHV-6 was detected in 18 patients, and 11 (61.1%) developed grades 2 to 4 acute GVHD. Of the 36 who were HHV-6 negative, only eight (22.2%) developed grades 2 to 4 acute GVHD. CMV and HHV-6 were detected in 13 patients, and eight (61.5%) developed grades 2 to 4 acute GVHD. Of the 23 who were negative for both CMV and HHV-6, only three (13%) developed grades 2 to 4 acute GVHD. In all experiments, the difference between the groups was significant (P<0.05, P<0.05 and P<0.01, respectively). We conclude that herpes virus infection, in particular CMV concurrent with HHV-6 reactivation, is predictive of moderate to severe acute GVHD.

Endothelial damage caused by cytomegalovirus and human herpesvirus-6.

Infection with cytomegalovirus (CMV) or human herpesvirus-6 (HHV-6) may have a role in vascular endothelial damage after bone marrow transplantation (BMT). In total, 41 patients who underwent BMT were classified into four groups (12, 10, 7, and 12 patients who were infected with both CMV and HHV-6, CMV alone, HHV-6, and neither virus, respectively). Levels of thrombomodulin, plasminogen activator inhibitor-1, and cyclic GMP were 7.5+/-1.7 FU/ml, 76.4+/-24.1 ng/ml, and 9.51+/-1.1 pmol/ml, respectively, in the patients with both viruses, while the respective values were 2.9+/-0.67 FU/ml, 33.8+/-8.09 ng/ml, and 2.90+/-1.4 pmol/ml in patients infected with CMV alone, 4.8+/-0.96 FU/ml, 47.7+/-9.21 ng/ml, and 5.48+/-0.55 pmol/ml in patients with HHV-6 alone, and 1.6+/-0.39, 17.5+/-7.88 ng/ml, and 0.45+/-0.3 in those with neither virus. All three markers were significantly higher in the three groups with at least one virus than in the uninfected patients (P<0.05), and were also higher in patients with HHV-6 alone than in those with CMV alone (P<0.05). These results suggest that infection by CMV or HHV-6 causes vascular endothelial injury, with HHV-6 having a stronger effect than CMV, and combined infection having a stronger effect than either virus alone. Such viral infection may be a cause of thrombotic microangiopathy after BMT.

Association of cytomegalovirus interstitial pneumonitis with HLA-type following allogeneic bone marrow transplantation.

Certain human leukocyte antigens may increase the risk of cytomegalovirus interstitial pneumonitis, an important complication of bone marrow transplantation. The prevalence of this pneumonitis was compared between patients possessing either HLA-B51 or HLA-B52 and patients without either antigen. The role of tumor necrosis factor-alpha in cytomegalovirus interstitial pneumonitis was also studied. Among 72 patients undergoing allogeneic bone marrow transplantation at our institution during the past 5 years, HLA-B51 or -B52 was detected in 29. Among these 29 patients, 13 (45%) developed cytomegalovirus interstitial pneumonitis, a significantly higher rate (P < 0.001) than among patients without these HLA types (4/43, 9%). In the pre-conditioning and stable phases, tumor necrosis factor-alpha levels were higher in patients with HLA-B51 or HLA-B52 than in patients without (P < 0.05; t-test). Throughout the period from pre-conditioning to around day 40, except on day 0, tumor necrosis factor-alpha levels were also significantly higher (P < 0.05 to P < 0.001) in patients developing cytomegalovirus infection than in those without it. These results suggest that HLA-B51 and HLA-B52 may be risk factors for cytomegalovirus interstitial pneumonitis after bone marrow transplantation, with an increase of tumor necrosis factor-alpha also being involved.