Expression patterns of placenta growth factor in human melanocytic cell lines

Expression patterns of the angiogenic placenta growth factor and its receptor neuropilin-1 were assessed in normal human melanocytes, SV40T-transformed melanocytes, and melanoma cells derived from primary and metastatic lesions. As determined by reverse transcription-polymerase chain reaction all primary and metastatic melanoma cell lines tested and SV40T-transformed melanocytes coexpressed two placenta growth factor splice variants (placenta growth factor-1 and -2) as well as neuropilin-1 mRNA. Placenta growth factor protein was detected in conditioned media derived from five of eight melanomas and from SV40T-transformed melanocytes. In contrast to melanoma cells, normal melanocytes did not express placenta growth factor mRNA at detectable levels and did not secrete placenta growth factor protein. By contrast, neuropilin-1 transcripts were detected in some of the normal melanocytes. Secretion of placenta growth factor by melanoma cells appeared to be constitutive because it was not affected by the addition of exogenous growth factors including insulin, epidermal growth factor, or basic fibroblast growth factor to culture media. Although melanoma cells expressed both, neuropilin-1 and flt-1, exogenous homodimeric placenta growth factor had no effect on melanoma cell growth. Similarly, placenta growth factor did not induce urokinase-type plasminogen activator production in these cells. These findings demonstrate that melanoma progression is accompanied by deregulated, constitutive placenta growth factor expression. Placenta growth factor, however, serves no apparent autocrine role in melanoma proliferation. Further studies are needed to define the relative contribution of placenta growth factor to the angiogenic properties of human melanomas.

Melanoma-associated expression of vascular endothelial growth factor and its receptors FLT-1 and KDR

The expression patterns of vascular endothelial growth factor (VEGF) and its two receptors, flt-1 and KDR, were assessed in normal human melanocytes, transformed melanocytes expressing the simian virus 40 Tgene (SV40T), and melanoma cells derived from primary and metastatic lesions. Constitutive expression of VEGF, flt-1, and KDR mRNA and proteins was observed in the majority of primary and metastatic melanoma cell lines, and in SV40T-transformed melanocytes. VEGF expression in melanoma cell lines was further enhanced by exogenous growth factors including insulin and fetal calf serum. By contrast, neonatal melanocytes did not express VEGF or VEGF receptors and VEGF expression could not be induced by exogenous growth factors. Exogenous VEGF had no significant effects on melanoma cell proliferation or on production of a transcriptional target for VEGF, urokinase-type plasminogen activator. Down-regulation of VEGF expression in the metastatic melanoma cell line WM164 through transfection of a VEGF antisense construct similarly did not affect proliferation of the transfected cells in the presence or absence of exogenous VEGF. In summary, coexpression of VEGF and its receptors is a tumor-associated phenomenon in melanoma development. However VEGF production does not support autocrine proliferation of the melanoma cell lines tested.

Serum levels of vascular endothelial growth factor and basic fibroblast growth factor in patients with soft-tissue sarcoma

PURPOSE

Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) have been suggested to be important mediators for tumor-induced angiogenesis. We measured serum VEGF and bFGF levels from patients with soft-tissue sarcomas and correlated serum VEGF and bFGF levels with tumor status at surgery and histological grading.

MATERIALS AND METHODS

A group of 18 healthy controls and 85 patients with soft-tissue sarcoma were enrolled in this study. The patients were classified according to tumor status at surgery. Serum levels of VEGF and bFGF were also correlated with histological grading. VEGF and bFGF levels were determined by enzyme-linked immunosorbent assay (Quantikine R&D Systems).

RESULTS

Serum VEGF and bFGF levels were significantly elevated in the patient group (VEGF: 580pg/ml, bFbF: 21pg/ml, P = 0.0001). The highest concentrations of serum VEGF and bFGF were found in patients with macroscopic tumor lesions or G3 histology. Serum VEGF levels showed a statistically significant correlation with tumor status and grading (P = 0.006 for tumor status, P = 0.0001 for grading).

CONCLUSIONS

This study reveals that elevated preoperative serum VEGF and bFGF levels can be detected in the majority of patients with soft-tissue sarcoma. The significant correlation with tumor mass and histological grading suggests that a consecutive monitoring of VEGF and bFGF in the serum of patients with soft-tissue sarcoma might be a valuable marker for tumor follow-up.

c-kit mutation and osteopetrosis-like osteopathy in a patient with systemic mast cell disease

We describe the case of a 69-year-old man with systemic mastocytosis and severe osteopetrosis who carries a somatic activating mutation in the c-kit proto-oncogene. The patient initially presented with urticaria pigmentosa, progressing to systemic mast cell disease with severe anemia due to bone marrow involvement, chronic diarrhea, and hepatosplenomegaly. Direct sequencing using amplimers from reverse transcriptase-polymerase chain reactions (RT-PCR) from skin mast cell-derived RNA revealed a point mutation in the c-kit proto-oncogene at position 2468, introducing a new recognition site for the restriction endonuclease HinfI. Treatment with interferon-alpha 2a, prednisone, and erythropoietin was initiated. Subsequently, clinical symptoms improved significantly and hemoglobin levels are now stable at 13 g/dl.

Chemotherapy with cisplatin and paclitaxel in patients with locally advanced, recurrent or metastatic oesophageal cancer

Single-agent therapy with paclitaxel is effective against both squamous cell carcinoma and adenocarcinoma of the oesophagus. However, only limited data are available on the combination of paclitaxel with other cytotoxic drugs in this entity. Patients with unresectable stage III, recurrent or metastatic tumours were treated in a multicentre setting with paclitaxel 90 mg m(-2) given over 3 h intravenously, followed by cisplatin 50 mg m(-2). The courses were repeated every 14 days. Twenty patients with squamous cell carcinoma or adenocarcinoma of the oesophagus were evaluable for response. The overall remission rate was 40% (8/20), including 15% (3/20) clinically complete responses. Clinical benefit response, defined as relief of dysphagia and/or significant gain in weight, was achieved in 70% of the patients. Neutropenia of CTC grade 3 occurred only in 10% of the patients; no grade 4 neutropenia and no severe thrombocytopenia was encountered. CTC grade 4 neurotoxicity was seen in 5% of patients. Cisplatin/paclitaxel administered every 14 days, was effective in patients with poor prognosis oesophageal cancer and toxicity was acceptable.

Mixed malignant germ cell tumour of the liver

Germ cell tumours of the liver are rare neoplasms, with fewer than 20 cases reported in the literature following presentation as teratomas, choriocarcinomas or yolk sac tumours. We report a 52-year-old patient who complained of upper abdominal pain and anorexia. Ultrasonography and computed tomography of the abdomen revealed a large hepatic mass. Among the laboratory values we found elevated levels of alpha-fetoprotein and beta-chorionic gonadotropin. Repeated biopsies via CT scan, laparoscopy and laparotomy disclosed a poorly differentiated adenocarcinoma. Subsequently liver function deteriorated and, on the basis of clinical data highly suggestive of a malignant germ cell tumour, a modified chemotherapeutic protocol (PEI) was initiated. The elevated levels of alpha-fetoprotein and beta-chorionic gonadotropin declined rapidly, but the patient died 10 days later of liver dysfunction and bronchopneumonia. Subsequent autopsy confirmed the initial clinical diagnosis of a multilocular extragonadal malignant germ cell tumour of the liver with components of choriocarcinoma and embryonal carcinoma.

Transforming region of 243R E1A contains two overlapping but distinct transactivation domains

Conserved regions 1 and 2 as well as the amino terminus of E1A are required for the transforming activity of the E1A oncoprotein. We show here that the amino terminus of 243R E1A has transactivation activity when brought to a promoter in yeast. Recruitment to a specific promoter is essential. Mutagenesis studies correlated the transactivation function with the extreme amino terminus and the conserved region 1 of E1A. Cotransfection assays in rodent cells confirmed that two overlapping but distinguishable domains, amino acids 1-65 and 37-80, can transactivate independently when targeted to a promoter. We also observed that when recruited to the proliferating cell nuclear antigen (PCNA) promoter, the amino-terminal region was sufficient to transactivate the PCNA promoter. On the other hand, deletion of the amino terminus of E1A resulted in failure to induce PCNA expression. Fusion of VP16 with the amino-terminal-deleted E1A mutant was able to restore the ability to induce the PCNA promoter. We further show that the amino-terminal region also is required for 243R E1A to repress the transactivation mediated by a universal transactivator DBD.VP16 and DBD.E1A. This repression could be specifically relieved by overexpression of TBP but not TFIIB. In addition, we show that the amino terminus of E1A is involved in in vitro interaction with the TATA binding protein (TBP). Thus the amino-terminal transforming region of E1A may regulate cellular gene expression in species that are distant in evolution via a common mechanism, functionally targeting TBP.

Expression of FLT4 and its ligand VEGF-C in acute myeloid leukemia

FLT4 represents a recently cloned member of class III receptor tyrosine kinases which include receptors for the angiogenic growth factor VEGF, namely FLT1 and KDR. The ligand of FLT4 has been identified as VEGF-C which shares sequence homology with VEGF and P1GF. In the adult FLT4 shows a restricted expression pattern that is limited to lymphatic endothelia and endothelia of some high endothelial venules (HEV). FLT4 has also been detected in some tumor cell lines including the hematopoietic line HEL. We therefore investigated expression of FLT4 and its ligand VEGF-C in fresh samples from patients with AML. Using a sensitive PCR method we detected FLT4 m-RNA in 15 of 41 patients with de novo AML at diagnosis or relapse and in three of 12 patients with secondary AML. FLT4 expression was confirmed by immunocytochemistry in a subgroup of the studied patient population. FLT4 was also found in leukemic cell line U937, but not TF-1 and KG1a. VEGF-C expression was found in leukemic samples of four of seven FLT4-positive and four of six FLT4-negative patients. U937 cells also produced VEGF-C m-RNA. Interestingly, FLT4 expression was not detected in bone marrow samples of 15 normal volunteer donors or in CD34-positive cells from three additional donors. Possible autocrine and paracrine growth stimulation of leukemic blasts by VEGF-C is currently being investigated in our laboratory.

Vascular endothelial growth factor, a possible paracrine growth factor in human acute myeloid leukemia

Vascular endothelial growth factor (VEGF) is a multifunctional cytokine involved in angiogenesis, inflammation, and wound healing. It is secreted by a variety of tumor cell lines, including hematopoietic lines. Therefore, we investigated expression of VEGF and its receptors on fresh leukemic blasts. VEGF-specific transcripts were detected by polymerase chain reaction (PCR) in 20 of 28 patients with de novo acute myeloid leukemia (AML) and in 3 of 5 patients with secondary AML. Using immunocytochemistry, we found VEGF protein in 2 leukemic cell lines and in 8 AML patients, in concordance with PCR results. Supernatants of fresh leukemic cells from 24 AML patients contained significantly more VEGF than supernatants from bone marrow cells of 9 normal donors or of CD34-enriched cells from 3 normal volunteer donors as determined by an enzyme-linked immunosorbent assay. VEGF possesses two high-affinity receptors, KDR and FLT1. Using a sensitive nested PCR assay, we detected expression of FLT1 in 10 of 20 patients with de novo AML and 3 of 5 patients with secondary AML. KDR was expressed in 4 of 22 patients with de novo AML and 1 of 4 with secondary AML. To study possible paracrine growth stimulation of AML blasts, endothelial cells from human umbilical cords were incubated with increasing concentrations of VEGF. A dose-dependent increase of granulocyte-macrophage colony-stimulating factor secretion from endothelial cells was identified.

Prolonged administration of interferon-alpha in patients with chronic-phase Philadelphia chromosome-positive chronic myelogenous leukemia before allogeneic bone marrow transplantation may adversely affect transplant outcome

To assess the influence of pretransplant cytoreductive therapy with special reference to interferon-alpha (IFN-alpha) treatment on major endpoints of allogeneic bone marrow transplantation (BMT), we studied 133 consecutive patients with Philadelphia chromosome (Ph1)-positive chronic myelogenous leukemia (CML) in first chronic phase who received marrow grafts from HLA-identical family (n = 103) or alternative donors (n = 30) at a referral-based transplant center. Fifty of these patients (38%) were previously exposed to IFN-alpha for a median duration of 14 months (range, 1 to 61 months), whereas 83 patients (62%) exclusively received hydroxyurea and/or busulfan therapy between 1 and 129 months (median, 15 months) pretransplant. Using the categorized treatment duration with each pretransplant cytoreductive agent as a measure for individual patient exposure to each agent, prolonged ( > 12 months) IFN-alpha administration was identified as the sole significant pretransplant therapy-related predictor of transplant outcome by proportional hazards regression analysis. The adjusted risk ratio (RR) of transplant-related mortality (TRM) was 2.5-fold higher (95% confidence limits [95% CL], 1.4 to 4.5; P < .004) compared with other pretransplant therapy and this was mainly attributable to a 3.1-fold higher RR (95% CL, 1.4 to 6.4; P < .005) of fatal posttransplant infections after prolonged IFN-alpha treatment pretransplant. Marrow graft failure developed exclusively among 7 of 30 patients (23%) with donors other than HLA-identical family members and was further restricted to patients who had been previously exposed to IFN-alpha. The probability of graft failure was 49% +/- 28% in 17 patients pretreated with IFN-alpha compared with 0% for the other 13 patients with mismatched family or unrelated donors (P < .008). In addition, a significant delay in neutrophil and platelet count reconstitution was observed among patients with donors other than HLA-identical family members after pretransplant IFN-alpha exposure. No influence of pretransplant cytoreductive therapy on either acute and chronic graft-versus-host disease or leukemic relapse was detected in this study. As a consequence of its adverse effect on TRM, prolonged pretransplant IFN-alpha treatment was independently associated with a 2.5-fold lower likelihood (95% CL, 1.4 to 4.5; P < .003) of 5-year overall survival and with a 2.3-fold lower likelihood (95% CL, 1.3 to 4.2; P < .004) of 5-year disease-free survival postransplant after adjustment for other significant prognostic factors in multivariate analysis.(ABSTRACT TRUNCATED AT 400 WORDS)

Transforming growth factor beta production and responsiveness in normal human melanocytes and melanoma cells

Previous studies have shown that some human melanoma cells express transforming growth factor beta (TGF-beta) mRNA and are growth inhibited by exogenous TGF-beta, suggesting a possible negative autocrine role for this melanoma-derived growth factor. To better understand the role of endogenous TGF-beta in the development of melanoma, we investigated patterns of TGF-beta protein production and responsiveness of human melanoma cells as compared to normal melanocytes. Both cultured melanoma cells and normal melanocytes secreted biologically inactive, latent TGF-beta protein which, upon acid treatment, became biologically active. In melanoma cells, TGF-beta production occurred constitutively, i.e., in the absence of exogenous polypeptide growth factors. By contrast, in melanocytes, TGF-beta production depended on stimulation by exogenous growth factors such as insulin-like growth factor I. Exogenous, bioactive TGF-beta 1 at picomolar concentrations inhibited tritiated thymidine uptake of normal melanocytes, whereas melanoma cells demonstrated various degrees of resistance to TGF-beta-induced inhibition of DNA synthesis. Five of six cell lines were less sensitive than any of the melanocyte lines tested, and one cell line was completely resistant to inhibitory effects of TGF-beta on DNA synthesis. In vivo selection of melanoma cells for metastatic ability in athymic mice produced a variant cell line that was resistant to TGF-beta 1-induced inhibition of DNA synthesis and proliferation. Development of TGF-beta resistance in the variant cell line was not associated with changes in TGF-beta cell surface binding. Stable transfection of melanocytes with a plasmid expressing the Simian Virus 40 large T-antigen rendered these cells resistant to growth inhibition by TGF-beta, suggesting that TGF-beta inhibits melanoma/melanocyte growth via interaction with Simian Virus 40 large T-antigen-responsive transcription elements.

Negative regulation of the major histocompatibility complex class I enhancer in adenovirus type 12-transformed cells via a retinoic acid response element

In cells transformed by the highly oncogenic adenovirus type 12 (Ad12), the viral E1A proteins mediate transcriptional repression of the major histocompatibility class I genes. In contrast, class I transcription is not reduced in cells transformed by the nononcogenic Ad5. The decreased rate of class I transcription is, at least in part, the result of a reduced major histocompatibility complex class I enhancer activity in Ad12-transformed cells and correlates with an increase in the levels of a DNA-binding activity to the R2 element of the enhancer (R. Ge, A. Kralli, R. Weinmann, and R. P. Ricciardi, J. Virol. 66:6969-6978, 1992). Employing transient transfection assays, we now provide direct evidence that the R2 element can confer repression in Ad12- but not Ad5-transformed cells. Repression by R2 was observed only in the presence of the positive enhancer element R1 and was dependent on (i) the number of the R2 elements and (ii) the relative arrangement of R2 and R1 elements. The putative R2-binding repressor protein, R2BF, was similar in molecular weight and binding specificity to members of the thyroid hormone/retinoic acid (RA) receptor family. RA treatment abrogated the R2-mediated repression in Ad12-transformed cells and had no effect on the activity of R2/R1-containing promoters in Ad5-transformed cells. These results are consistent with the presence of an R2-binding repressor in Ad12-transformed cells. In the absence of RA, the repressor compromises enhancer activity by interfering with the activity of the positive cis element R1. RA treatment of Ad12-transformed cells may render the repressor inactive.

Evidence that sustained growth suppression of intestinal anaerobic bacteria reduces the risk of acute graft-versus-host disease after sibling marrow transplantation

The influence of intestinal bacterial decontamination on the occurrence of grades II to IV acute graft-versus-host disease (GVHD) was retrospectively analyzed in 194 predominantly adult patients treated by genotypically identical sibling marrow transplantation under conditions of strict protective isolation and intestinal antimicrobial decontamination. Forty-five patients (23%) developed acute GVHD and univariate analysis identified four features that significantly increased the risk for this reaction: chronic myeloid leukemia as the underlying disease, as compared with all other disease categories (P < .0001); female marrow donors for male recipients, as compared with other gender combinations (P < .005); ineffective, as compared with sustained growth suppression of intestinal anaerobic bacteria (P < .006); and methotrexate as the sole immunoprophylactic compound, as compared with cyclosporine containing regimens (P < .05). Using the duration of anaerobic growth suppression as a time-dependent explanatory variable, proportional hazards regression analysis confirmed these features as independent predictors for acute GVHD with relative risk estimates of 1.9 (95% confidence interval [CI], 1.3 to 2.7) for the immunoprophylactic regimen (P < .0004), of 1.8 (95% CI, 1.3 to 2.5) for the underlying disease (P < .0005), of 1.7 (95% CI, 1.2 to 2.5) for anaerobic decontamination (P < .002), and of 1.3 (95% CI, 1.1 to 1.6) for the donor/recipient gender combination (P < .008), respectively. Best subset selection modeling also identified the quality of anaerobic decontamination as the third most important predictor for acute GVHD, when all four significant features were included. Estimates of acute GVHD stratified by the quality of anaerobic bacterial growth suppression showed a strong influence of anaerobic decontamination in patients burdened by at least one of the other unfavorable factors (P < .009). In conclusion, this study provides strong evidence that sustained growth suppression of intestinal anaerobic bacteria after clinical sibling marrow transplantation can independently modulate the occurrence of grades II to IV acute GVHD, which is in concordance with previous results from animal transplantation models. Antimicrobial chemotherapy specifically targeted to the intestinal anaerobic bacterial microflora may be complementarily useful in preventing acute GVHD and should be investigated in a prospective trial.

In vitro growth patterns of normal human melanocytes and melanocytes from different stages of melanoma progression

Based on the clinicopathological classification of distinct stages of tumor progression in the melanocytic system, we have investigated the in vitro growth patterns and requirements of normal melanocytes and melanocytes isolated from different lesions of melanoma progression. Normal melanocytes depend on a combination of insulin-like growth factor (IGF-I) or insulin, 12-O-tetradecanoyl phorbol-13-acetate (TPA), alpha-melanocyte stimulating hormone (alpha-MSH), and basic fibroblast growth factor (bFGF) for in vitro proliferation. Nevus cells display a reduced need for TPA and are largely independent of bFGF. Both melanocytes and nevus cells have a finite lifespan in vitro and show no spontaneous transformation, whereas melanoma cells can be grown indefinitely in vitro. Cells from primary melanomas require only IGF-I or insulin for continuous growth, and metastatic melanoma cells can proliferate in base medium without addition of any growth factors or proteins. This progressive growth autonomy is paralleled by an increased competence for endogenous growth factor production. Among these growth factors, bFGF and melanoma growth-stimulatory activity (MGSA) act in an autocrine fashion. Melanoma-derived growth factors without apparent autocrine function, such as platelet-derived growth factor A and B (PDGF-A and PDGF-B) and transforming growth factor-alpha (TGF-alpha), might still be important for melanoma growth by stimulating surrounding normal fibroblasts, endothelial cells, or keratinocytes to secrete growth-promoting factors. The significance of growth factors such as transforming growth factor-beta (TGF-beta) and melanoma-inhibiting activity II (MIA II), which have a potentially negative autocrine function, remains unknown. The successful propagation of melanocytic cells of all stages of melanoma progression has yielded valuable insight into the mechanisms of growth regulation and malignant transformation.

Characterization of tenascin secreted by human melanoma cells

Tenascin is a large glycoprotein of the extracellular matrix. It shows a site-restricted expression during embryogenesis and can be found in adult tissues during wound healing and tumorigenesis. Because of the potential involvement of tenascin in adhesion and invasion during metastasis, the study of the interactions of tumor cells with tenascin is of considerable interest. Using five anti-melanoma monoclonal antibodies to four different epitopes of human tenascin, we found that most melanoma cells secrete tenascin in vitro constitutively. Transforming growth factor beta 1 in the medium increased secretion in tenascin-producing cells. Tenascin was present in sera of melanoma patients, with significantly elevated levels in patients with advanced melanomas as compared to patients with low tumor burden or to normal donors. Normal and malignant melanocytes did not attach to tenascin as substrate within 1 to 2 h and tenascin could also inhibit fibronectin-dependent adhesion. These results indicate that tenascin may play a critical role in cell-substrate interactions of melanoma cells.

[Maintenance of remission in acute myeloid leukemia by allogeneic or autologous bone marrow transplantation]

Over a 10-year period 120 patients (58 women, 62 men; median age 33 [14-53] years) with acute myeloid leukaemia were treated by allogenic (n = 90) or autologous bone marrow transplantation to maintain remission. After a median observation time of 41 (11-126) months 64 patients (53%) remain alive without recurrence of leukaemia. Ten years after allogenic transplantation performed during the first complete remission the probability of disease-free survival is 50 +/- 8%, as compared with 50 +/- 9% at 4.5 years after autologous transplantation. Significant factors influencing disease-free survival after allogenic transplantation during the first complete remission were the time interval up to the onset of remission and the length of the remission before transplantation. The chance of disease-free survival after allogenic transplantation in the second complete remission does not so far differ from the results achieved by transplantation in the first complete remission. The risk of recurrence after autologous transplantation in the first complete remission (47 +/- 10%) is significantly higher than that following allogenic transplantation (18 +/- 10%, P less than 0.0001). Acute graft versus host reactions occurred in 16% and chronic reactions in 36% of patients after allogenic transplantation. The mortality was 38% after allogenic transplantation and 7% after autologous transplantation.

Initial treatment of acute graft-versus-host disease with a murine monoclonal antibody directed to the human alpha/beta T cell receptor

A murine IgG2b monoclonal antibody directed to the constant part of the human alpha/beta T cell receptor (BMA031) was investigated in a pilot study as an initial treatment for acute graft-versus-host disease (aGvHD) after allogeneic bone marrow transplantation. The treatment protocol consisted of 5 mg BMA031 on 5 consecutive days with continuation of the prophylactic baseline immuno suppression using cyclosporin. Seven patients with grades II-III acute graft-versus-host disease were entered on the protocol and six patients completed the full treatment course. Mild to moderate acute adverse reactions to the first BMA031 infusion occurred in three patients. A nearly complete decline of circulating T lymphocytes was observed during BMA031 therapy, but the T cells returned to pretreatment values within 1 week after the last infusion. Serum pharmacokinetics of free antibody best fitted to a two-compartment open model with a mean initial half-life of 6 h and an estimated mean terminal half-life of 40 h. One patient developed antimurine antibodies of the IgM subclass. In five patients a complete and sustained resolution of all disease manifestations was attained, while in one patient a temporary response of skin involvement with aGvHD was noted. These results indicate that BMA031 can be safely administered as initial treatment of aGvHD. The therapeutic responses observed warrant its further clinical evaluation in this setting.

Clinical results and the Essen concept of TBI

Total body irradiation (TBI) prior to bone marrow transplantation (BMT) is applied for treatment of 230 patients in the period 1975-1988. The clinical results of 169 patients treated by four different TBI dosage and treatment techniques are analysed. The risk of leukemic relapse is low after fractionated TBI (9%) as well as after single dose TBI (14%). The lowest frequency of interstitial pneumonitis (21%) occurred when the patient translation technique was used for fractionated homogeneous pa/ap TBI with 10 Gy (8 Gy lung dose) in 4 fractions in 4 days. Prophylaxis of GVHD and the modus of protective environment were two other factors which influence the risk of IP.