Responses to immunization in the thymus of the adult mouse.

The rate of synthesis of RNA in the thymus glands of adult mice increased after immunization with sheep red blood cells (SRBC). The specific activity of some fractions of RNA, separated first by density gradient centrifugation and then by polyacrylamide gel electrophoresis, was 16-fold higher on day 3 after immunization than control mice not injected. RNA synthesis in the thymus was inhibited by rabbit anti-mouse thymus serum, injected along with antigen. A material was found in RNA extracts from the thymus glands of mice immunized with SRBC which converted a small proportion of either spleen cells or peritoneal cells from nonimmunized mice to form sheep cell hemolysins. Neither extracts from the glands of nonimmunized mice nor the livers of immunized mice were active. Extracts from the thymus glands of mice immunized with rabbit red blood cells (RRBC) were inactive and activity was destroyed by ribonudease. The residual antigen content was not determined. Biologically active extracts from the thymus had a different electrophoretic mobility from active extracts from the spleen.

T-regulatory cells are relatively deficient in squamous carcinomas undergoing regression in mice immunized with a squamous carcinoma vaccine enriched for immunotherapeutic cells.

In a prior report (Int J Cancer 2006; 119: 339-348), we described a new vaccination strategy for squamous cell carcinoma (SCC). The vaccine was prepared by transfer of unfractionated DNA-fragments (25 kb) from KLN205 cells, a squamous carcinoma cell line (DBA/2 origin; H-2(d)) into LM cells, a highly immunogenic mouse fibroblast cell line (C3H/He origin; (H-2(k))). As only a small proportion of the transfected cell population was expected to have incorporated DNA segments that included genes specifying antigens associated with the squamous carcinoma cells, we devised a novel strategy to enrich the vaccine for immunotherapeutic cells. Enhanced immunity to squamous carcinoma was induced in tumor-bearing mice treated solely by immunization with the enriched vaccine, which translated into prolonged survival without toxicity. Here, we describe the characteristics of the cell populations infiltrating established squamous carcinomas undergoing regression in mice immunized with vaccines enriched for immunotherapeutic cells. The results indicated that CD8+ T cells were predominant and that T-regulatory cells (FoxP3+, CD4/CD25+, CD4/CD62L(high), CD4/CTLA-4e) were relatively deficient in the regressing tumors. Inflammatory infiltrates were not detected in various organs and tissues of mice immunized with the DNA-based vaccine.

New strategy for the identification of squamous carcinoma antigens that induce therapeutic immune responses in tumor-bearing mice.

This study describes a new strategy for the identification of squamous carcinoma antigens tumor-associated antigens (TAA). The antigens were discovered by comparing microarrays of squamous carcinoma vaccines highly enriched for immunotherapeutic cells with non-enriched vaccines. The vaccines were prepared by transferring sheared genomic DNA fragments (25 kb) from KLN205 cells, a squamous carcinoma cell line (DBA/2 mouse origin (H-2(d)) into LM fibroblasts (C3H/He origin, H-2(k)). The transferred tumor DNA segments integrate spontaneously into the genome of the recipient cells, replicate as the cells divide and are expressed. As only a small proportion of the transfected cell population was expected to have incorporated DNA segments that included genes specifying TAA (the vast majority specify normal cellular constituents), a novel strategy was employed to enrich the vaccine for TAA-positive cells. Microarrays were used to compare genes expressed by enriched and non-enriched vaccines. Seventy-five genes were overexpressed in cells from the enriched vaccine. One, the gene for Cytochrome P450 (family 2, subfamily e, polypeptide 1) (Cyp2e1), was overexpressed in the enriched but not the non-enriched vaccine. A vaccine for squamous carcinoma was prepared by transfer of a 357 bp fragment of the gene for Cyp2e1 into the fibroblast cell line. Robust immunity, sufficient to result in indefinite survival, was induced in tumor-bearing mice immunized with cells transfected with this gene fragment.

[The physiopathology of dialysis-associated hypertension]. / La physiopathologie de l'hypertension artérielle en dialyse chronique.

Hypertension in subjects on long term dialysis is frequent. Its origins are found in extracellular volume overload, which is complicated by increased peripheral arterial resistance. The latter is affected by many systems, including that of renin-angiotensin, endothelin, nitric oxide, the sympathetic nervous system, and others. The interaction between these factors may explain why the control of hypertension in dialysis patients requires ongoing attention to the many aspects of good dialysis.

Complement sensitivity of somatic hybrids of a complement-resistant murine leukemia cell line.

RADA-1 cells (H-2a), a murine leukemia cell line maintained by serial transfer in histocompatible recipients expressing thymus-leukemia (TL) 1, 2, 3 antigenic determinants, resisted the cytotoxic effects of guinea pig complement (GPC) and TL antiserum. The cells expressed a lower density of TL antigens than did ASL-1 cells, another TL(+) leukemia cell line expressing the same determinants and susceptible to complement (C)-mediated lysis. Stable somatic cell hybrids of RADA-1 cells and LM(TK)- cells (H2k), a TL(minus) thymidine kinase-deficient mutant of mouse L cells, were selected in hypoxanthine-aminopterin-thymidine medium. The hybrid cells expressed the H-2 antigens of both parents and shared a hybrid karyotype. They formed TL 1, 2, 3 antigens as determined by immunofluorescence, mixed hemagglutination methods, the direct isolation of TL antigens from Nonidet P40 extracts of the cells, and the capacity of the cells to reduce by absorption the known titers of TL antiserum. These hybrid cells lost the capacity to resist lysis by TL antiserum and GPC. They were susceptible to the cytotoxic effects of TL 1, 2, 3; TL 2; OR TL 1, 3 antiserum and GPC, even though the density of TL antigens associated with the cells was approximately 25% of their resistant RADA-1 parental cells. These results indicated that the mechanism of resistance to C-mediated lysis was genetically separable from the expression of TL antigens by the cells and that the susceptibility of the cells to the cytotoxic effects of antiserum was related only in part to the density of TL antigens expressed by the cells.

Detection of thymus leukemia antigens on the surface membranes of murine leukemia cells resistant to thymus leukemia antibodies and guinea pig complement.

The thymus leukemia (TL) antigens of ASL-1 murine leukemia reversibly disappeared from the membranes of cells exposed to TL antisera; the cells acquired resistance to fresh TL antiserum and complement (antigenic modulation). Three independent methods, however, indicated that the acquisition of complement resistance preceded the complete disappearance of TL antigens from the cell surface. Modulated cells reduced known titers of TL antisera by absorption; they stained positively in immunofluorescence studies involving TL antibodies and fluorescence-labeled rabbit anti-mouse immunoglobulin. TL antigens labeled previously with 125I were recovered by immunoprecipitation from cellular extracts prepared with nonionic detergent. Continued exposure of the cells to TL antiserum led to virtually complete disappearance of the antigens. Similar results were obtained for RADA-1 cells, another murine leukemia that forms TL antigens, although in this instance the cells were resistant to the cytolytic effects of TL antisera and guinea pig complement (GPC) without prior exposure to TL antibodies. The density of TL antigens remaining on the surface of different TL(+) cell types failed to correlate with resistance to TL antibodies and GPC. Cells from F, hybrids of TL(+) and TL(-) mouse strains formed TL antigens and were susceptible to TL antibodies and GPC even though the density of TL antigens formed by the susceptible cells was less than the density of TL antigens formed by modulated cells. Stable somatic hybrids of RADA-1 cells and TL(-) cells formed TL antigens at lower density than did RADA-1 cells and lysed in the presence of aliquots of the TL antisera and GPC used in previous tests.

Detection of a TL(+) murine leukemia cell line that resists the cytotoxic effects of guinea pig complement and specific antiserum.

RADA-1 cells [H-2a thy-1b; thymus-leukemia (TL) 1, 2, 3], a radiation-induced murine leukemia cell line maintained by serial transfer in histocompatible recipients, resisted lysis by guinea pig complement (GPC) and TL 1, 3; TL 2; or TL 1, 2, 3 antiserum. The cells expressed TL antigenic specificities as determined by indirect fluorescent antibody methods, the direct isolation of TL antigens from the cells, and the capacity of the cells to reduce known titers of TL antisera. GPC was consumed to the same extent during the reaction of resistant cells and TL antisera as occurred in the reaction of sensitive cells (killed under similar conditions) and TL antisera. RADA-1 cells were not nonspecifically resistant to complement (C)-mediated lysis; they were killed in the presence of H-2a antiserum and GPC. The TL antisera contained antibodies for TL determinants. They stimulated the C-mediated lysis of ASL-1 cells (TL 1, 2, 3) and thymocytes from strain A mice (TL 1, 2, 3). The TL antigens of resistant RADA-1 cells underwent antigenic modulation, the reversible disappearance of TL antigens from the cells stimulated by specific antiserum. After the cells were treated with neuraminidase, they became susceptible to the cytotoxic effects of aliquots of the same TL antisera and GPC used previously.

Interleukin-2-secreting mouse fibroblasts transfected with genomic DNA from murine melanoma cells prolong the survival of mice with melanoma.

A retrovirus was used to introduce a provirus (pZipNeoSVIL-2) containing the gene for interleukin-2 (IL-2) along with a neor gene (confers resistance to G418) into LM cells, a mouse cell line expressing defined major histocompatibility complex class I antigens (H-2k). After initial selection in growth medium containing G418, IL-2 secretion was confirmed, and the cells were then cotransfected with genomic DNA from B16F1 or B16F10 melanoma cells, along with DNA from a plasmid (pHyg) that confers resistance to hygromycin. After a second round of selection in growth medium containing sufficient quantities of hygromycin to kill 100% of nontransfected cells but without further modification, the unfractionated populations of transfected cells were tested for their immunotherapeutic properties in C57BL/6 mice (H-2b) with established B16 melanomas (H-2b). Animals with melanomas treated with either of the transfected cell populations survived significantly (P < 0.01) longer than untreated mice or mice treated with irradiated (5000 rads) B16F1 melanoma cells. The animals also survived longer (P < 0.05) than mice with melanoma treated with IL-2-secreting LM cells transfected with genomic DNA from MOPC-315 cells, a nonimmunologically cross-reactive murine tumor. As determined by the capacity of monoclonal antibodies to T-cell subsets to inhibit the antimelanoma response in a 51Cr release assay, the antimelanoma immunity in mice immunized with cells transfected with genomic DNA from either B16F1 or B16F10 cells was mediated primarily by Lyt-2.2+ T-cells. These data raise the possibility that a generic, live cell tumor vaccine can be developed that can be modified to provide specificity for the neoplasms of individual patients.

Estimation of the number of genes specifying the heavy chain of mouse thymus leukemia antigens.

We have investigated the number of structural genes present in ASL-1 cells, a murine leukemia cell line which encodes the heavy chain of thymus leukemia (TL) antigens, a protein which is similar to the Class I histocompatibility antigens. TL-specific messenger RNA was purified from polysomes of ASL-1 cells by immunoprecipitation, and this messenger RNA translated in vitro to produce a Mr 42,000 protein which comigrated on acrylamide gel with nonglycosylated TL heavy chain. A 32P-labeled complementary DNA (cDNA) was synthesized by reverse transcription of the TL-specific messenger RNA as template. Analysis of reassociation kinetics of the 32P-TL-cDNA with DNA from ASL-1 cells showed that the kinetics was indistinguishable from that obtained using a DNA encoding a single-copy gene (C mu). An analysis was performed in which DNA from ASL-1 cells was subjected to digestion with each of three restriction enzymes and hybridized with 32P-TL-cDNA according to the Southern "blot" technique. Two bands formed hybrids with the 32P-TL-cDNA with each of three restriction enzymes used. These data are consistent with the presence of a small number of structural genes for the TL heavy chain in the genome of ASL-1 leukemia cells.

Immunity to murine breast cancer cells modified to express MUC-1, a human breast cancer antigen, in transgenic mice tolerant to human MUC-1.

The high incidence of breast cancer in women and the severity of the disease have stimulated a need for improved and novel forms of therapy. The product of the MUC-1 gene has been identified as a breast cancer-associated antigen in breast cancer patients. The gene has been cloned and sequenced. Transgenic mice were prepared that express human mucin and are naturally tolerant to the molecule, providing a unique opportunity to investigate immunotherapeutic strategies in experimental animals that might eventually be applied to breast cancer patients. A cell line (410.4) derived from a mouse mammary adenocarcinoma that arose in a BALB/c mouse was transduced with a retroviral vector (R1-MUC1-pEMSVscribe) that encoded MUC-1. After confirmation of the expression of human mucin, the cells (E3) were further modified by transduction with retroviral vectors encoding interleukin (IL)-2, IL-4, IL-12, or IFN-gamma to evaluate the effect of cytokine-secretion on the immunogenic properties of the cells in the MUC-1 transgenic mice. The results indicated that modification of the breast cancer cells to secrete IL-12 reduced and at times eliminated the tumorigenic growth properties of the cells. Under similar circumstances, progressively growing tumors formed in MUC-1 transgenic mice that received injections of unmodified E3 cells or with E3 cells modified to secrete IL-2, IL-4, or IFN-gamma. Immunity to breast cancer developed in MUC-1 transgenic mice that had rejected IL-12-secreting E3 cells because the animals were resistant to challenge with (non-cytokine-secreting) E3 cells. In vitro analyses confirmed the presence of T cell-mediated cytotoxicity toward the breast cancer cells in MUC-1 transgenic mice immunized with the IL-12-secreting cells. Our data obtained in a unique animal model system point toward an analogous form of therapy for breast cancer patients.

DNA-based vaccines for the treatment of cancer--an experimental model.

Antigenic differences between normal and malignant cells form the basis of clinical immunotherapy protocols. Because the antigenic phenotype varies widely among different cells within the same tumor mass, immunization with a vaccine that stimulates immunity to a broad array of tumor antigens expressed by the entire population of malignant cells is likely to be more efficacious than immunization with a vaccine for a single antigen. One strategy is to prepare a vaccine by transfer of DNA from the patient's tumor into a highly immunogenic cell line. Weak tumor antigens, characteristic of malignant cells, become strongly antigenic if they are expressed by immunogenic cells. In animal models of melanoma and breast cancer, immunization with a DNA-based vaccine is sufficient to deter tumor growth and to prolong the lives of tumor-bearing mice.

Immunity to murine leukemia induced in susceptible mice by transfected mouse fibroblasts.

A cultured cell line of mouse fibroblasts was transfected with DNA from murine leukemia cells expressing a previously characterized tumor-associated antigen. Antigen-positive cells were used as immunogens in an immunotherapy protocol to determine if they stimulated resistance to the malignant proliferation of the leukemia in susceptible mice. For the experiments, LM(TK-) mouse fibroblasts, a thymidine kinase-deficient mouse cell line, were cotransfected with DNA from ASL-1 murine leukemia cells and the plasmid pSV2neo conferring resistance to Geneticin. Integration of the plasmid into cellular DNA was confirmed by restriction digest blot analysis. A/J mice, highly susceptible to the malignant proliferation of passively transferred ASL-1 leukemia cells, were immunized with the transfected cells. Animals receiving two prior injections of antigen-positive transfected cells and then challenged with an injection of viable ASL-1 cells survived longer than animals in the unprotected control group or in the group receiving immunizations with LM(TK-) cells transfected with plasmid only (p less than 0.01). Some of the mice appeared to have rejected the tumor and lived more than 80 days. One group of protected animals rechallenged with a second injection of ASL-1 cells, 40 days after the first, survived for more than 50 additional days, without evidence of recurrent disease.

Reversibility of long-standing urinary tract obstruction requiring long-term dialysis.

Urinary tract obstruction of longer than 4 to 6 weeks' duration is usually said to be irreversible. Older reports of unilateral obstruction have documented return of kidney function after longer periods of obstruction. The duration of bilateral obstruction compatible with return of life-sustaining renal function is poorly defined. We report herein three cases of long-standing urinary tract obstruction leading to apparent dialysis-dependent end-stage renal disease, where relief of obstruction eventually led to discontinuation of dialysis.

Phase I evaluation of interleukin-2-transfected irradiated allogeneic melanoma for the treatment of metastatic melanoma: appendix 1: protocol.

A cell line (UISO-H-MEL-2) was established from the neoplastic cells of a patient with malignant melanoma during the natural course of the patient's treatment. The melanoma cells express defined MHC Class I histocompatibility determinants including determinants specified by the HLA-A2 Class I allele, along with a common melanoma-associated T-cell epitope derived from the tyrosinase gene. The gene for human interleukin-2 (IL-2) was transduced into the cells with a provirus (pZipNeoSVIL-2), packaged in GP + envAM12 cells. Integration of the IL-2 gene into genomic DNA of the transduced cells and its expression were established. The IL-2-secreting cell line (UISO-H-MEL-2-IL-2) was found to be free of recombinant retroviruses and other infectious agents. The IL-2-secreting cells will be subjected to 5000 rads X-irradiation and administered to 12 informed patients with metastatic malignant melanoma in a Phase I toxicity study. The dose of X-irradiation was sufficient to inactivate one hundred percent of the cells, but insufficient to completely inhibit IL-2 synthesis during a fourteen-day period of analysis. Patients who have failed all standard forms of treatment will become eligible for inclusion in the study if they develop metastatic melanoma, and if their tumor cells express products of the tyrosinase gene. The patients will differ with the cellular immunogen at no less than three of six MHC Class I alleles, but will share identity at the HLA-A2 Class I allele. The patient's antimelanoma immune response to the injected cells will be determined by both in vivo and in vitro parameters. Background studies performed in inbred mice indicate that X-irradiated IL-2-secreting cells that express both melanoma-associated antigens and allogeneic Class I histocompatibility antigens are more antigenic in terms of their capacity to induce an antimelanoma response than X-irradiated IL-2-secreting melanoma cells. Of significance for the future potential of this form of therapy in melanoma patients, the period of survival of mice was established melanoma treated with the IL-2-secreting allogeneic cells was significantly (P < 0.001) longer than that of untreated animals, or animals treated with X-irradiated melanoma cells. An analogous protocol was reviewed and approved by the Recombinant DNA Advisory Committee of the National Institutes of Health.

Acquired cystic kidney disease: occurrence, prevalence, and renal cancers.

Acquired cystic kidney disease (ACKD) is the result of cyst formation in the failing kidney. It has become more common because of increases in retention of the patients' own kidneys, growth in the dialysis population, and survival of long-term dialysis patients. We studied our chronic dialysis population for ACKD and renal cancers, and conducted a literature review of ACKD and renal cancer. We analyzed our chronic dialysis patients from 1979 through 1989 for native kidney retention, and studied patients undergoing their first kidney transplant at our center from 1967 through 1989. Our patients and those in literature reports were characterized by age, sex, race, underlying renal disease, dialysis time, and survival. We found that: 1) Native kidney retention in dialysis and transplant patients has increased linearly over the past 10 to 20 years and is now greater than 90% in both groups; 2) ACKD occurs in ESRD patients with all types of underlying kidney disease. 3) ACKD affects CAPD patients and HD patients equally; 4) ACKD affects both sexes equally and age is not a factor in the development of ACKD; 5) there appears to be a greater prevalence of ACKD in black patients with ESRD as compared to white patients with ESRD; 6) the prevalence of ACKD is a function of time on dialysis; 7) the incidence of renal cancer in ESRD is increased over that of the general population and occurs 80% of the time in patients with ACKD; 8) renal cancer can develop at any time in patients with ESRD and also occurs in renal transplant recipients; 9) the incidence of renal cancer in ESRD is 5 to 7 times greater in males than in females, and blacks are affected nearly twice as often as whites; and 10) the 5-year survival of patients with renal cancer and ESRD is approximately 35%--similar to that of patients not on dialysis. ACKD is an important complication of ESRD and will grow in importance as the population at risk continues to increase. These results support the need for investigation of 3-year dialysis patients for the presence of cystic disease and appropriate therapy based on findings. Further study is needed to discern the quantitative importance of ACKD and renal cancers in renal transplant patients.

Interleukin-2-secreting mouse fibroblasts transfected with genomic DNA from murine neoplasms induce tumor-specific immune responses that prolong the lives of tumor-bearing mice.

Genetic alterations are a common feature of the malignant phenotype. Among other properties, altered genes may be responsible for invasion and metastasis, as well as for resistance to chemotherapeutic agents. Under appropriate circumstances, the products of other altered genes expressed by malignant cells may act as tumor-associated T-cell epitopes, capable of provoking antitumor immune responses. As a novel means of augmenting the immunogenicity of the gene products, unfractionated, sheared genomic DNA from various tumor cell lines (B16F1 melanoma, B16F10 melanoma, MOPC-315 plasmacytoma, C1498 lymphoma, or J558 myeloma), or from non-neoplastic liver cells of tumor-free mice, was transfected into LM cells, a mouse fibroblast cell-line (H-2k) that had been modified previously by retroviral gene transfer to secrete interleukin-2 (IL-2). The IL-2-secreting transfected cell populations were then tested for their immunogenic properties toward B16F1 (H-2b) or C1498 (H-2b) cells in syngeneic C57BL/6 mice. The antitumor responses were specific for the type of tumor from which the DNA was obtained. The survival of C57BL/6 mice injected with a mixture of viable B16F1 cells and IL-2-secreting LM cells transfected with DNA from B16F1 cells was significantly prolonged. In a similar manner, the survival of C57BL/6 mice injected with a mixture of C1498 cells and IL-2-secreting LM cells transfected with DNA from C1498 cells was prolonged as well. The immunity was mediated predominantly by CD8+ and natural killer/lymphokine-activated killer (NK/LAK) cells. These data raise the possibility that a cell line altered previously for cytokine secretion may be readily modified to provide immunologic specificity for the neoplasms of individual cancer patients.

Immunization with interleukin-2-secreting allogeneic cells transfected with DNA from mouse melanoma cells induces immune responses that prolong the lives of mice with melanoma.

Altered genes in tumor cells specify tumor-associated antigens. Because genetic instability is a characteristic of the malignant cell phenotype, a large number of different, altered genes may be present in a population of neoplastic cells, specifying an array of undefined tumor-associated determinants. We hypothesized that immunogenic cells transfected with DNA from malignant cells will include cells that specify tumor-associated antigens. To test this question, we deliberately mutagenized a population of B16 melanoma cells (H-2b) by ultraviolet-B irradiation. DNA from the surviving cells was used to transfect LM cells (H-2k), a mouse fibroblast cell line modified previously to secrete interleukin-2. The transfected allogeneic cells were then tested for their immunogenic properties in C57BL/6J mice (H-2b) syngeneic with the melanoma. Mice injected with a mixture of the mutagenized B16 cells and the transfected cells survived significantly longer than untreated mice injected with the mutagenized B16 cells alone. Mice injected with a mixture of mutagenized B16 cells and cells transfected with DNA from unirradiated B16 cells died in shorter intervals. Based on the results of cytotoxicity assays performed in vitro, the cellular immune responses of greatest magnitude were directed toward the type of cell from which the DNA was obtained.

ACE inhibitors and AII receptor antagonists in the treatment and prevention of bone marrow transplant nephropathy.

Radiation nephropathy has emerged as a major complication of bone marrow transplantation (BMT) when total body irradiation (TBI) is used as part of the regimen. Classically, radiation nephropathy has been assumed to be inevitable, progressive, and untreatable. However, in the early 1990's, it was demonstrated that experimental radiation nephropathy could be treated with a thiol-containing ACE inhibitor, captopril. Further studies showed that enalapril (a non-thiol ACE inhibitor) was also effective in the treatment of experimental radiation nephropathy, as was an AII receptor antagonist. Studies also showed that ACE inhibitors and AII receptor antagonists were effective in the prophylaxis of radiation nephropathy. Interestingly, other types of antihypertensive drugs were ineffective in prophylaxis, but brief use of a high-salt diet in the immediate post-irradiation period decreased renal injury. A placebo-controlled trial of captopril to prevent BMT nephropathy in adults is now underway. Since excess activity of the renin-angiotensin system (RAS) causes hypertension, and hypertension is a major feature of radiation nephropathy; an explanation for the efficacy of RAS antagonism in the prophylaxis of radiation nephropathy would be that radiation leads to RAS activation. However, current studies favor an alternative explanation, namely that the normal activity of the RAS is deleterious in the presence of radiation injury. On-going studies suggest that efficacy of RAS antagonists may involve interactions with a radiation-induced decrease in renal nitric oxide activity or with radiation-induced tubular cell proliferation. We hypothesize that while prevention (prophylaxis) of radiation nephropathy with ACE inhibitors, AII receptor antagonists, or a high-salt diet work by suppression of the RAS, the efficacy of ACE inhibitors and AII receptor antagonists in treatment of established radiation nephropathy depends on blood pressure control.

Treatment of radiation nephropathy with ACE inhibitors.

PURPOSE: A previous study showed that radiation nephritis could be treated with captopril, an angiotensin-converting-enzyme inhibitor. These studies were designed to determine whether other angiotensin-converting-enzyme inhibitors would be effective, whether captopril would inhibit the development of the histopathologic lesions typical of radiation nephritis, and whether captopril could be used to treat the nephropathy observed in bone marrow transplant recipients conditioned with total body irradiation. METHODS AND MATERIALS: In radiation nephritis studies, rats were given 17-27 Gy bilateral renal irradiation in 5 fractions. Six months after irradiation animals were stratified by blood urea nitrogen and assigned to no treatment, or treatment with captopril (500 mg/l) or enalapril (50 mg/l) in the drinking water. A subset of animals was sacrificed for histopathology after 3 months; the remaining animals continued on drugs for 7 months. In the bone marrow transplant nephropathy study, rats received 14-17 Gy total body irradiation in 6 fractions over 3 days followed by syngeneic bone marrow transplant. Six months after irradiation, animals were stratified by blood urea nitrogen and assigned to no treatment, or treatment with captopril (500 mg/l). Animals remained on drugs for 6 months. In all studies animals were followed with periodic renal function tests. RESULTS: In the radiation nephritis study, survival and renal function were significantly enhanced by both captopril and enalapril, but there were no significant differences between the drugs. The histopathologic severity of the lesions of radiation nephritis correlated with the degree of renal dysfunction; and in irradiated animals with equal initial azotemia, captopril-treated rats developed less severe renal lesions. Finally, captopril also prolonged survival and preserved renal function in this rat bone marrow transplant nephropathy model. CONCLUSION: Angiotensin-converting-enzyme inhibitors are an effective treatment for both radiation nephritis and bone marrow transplant nephropathy.

Influence of renal shielding on the incidence of late renal dysfunction associated with T-lymphocyte deplete bone marrow transplantation in adult patients.

Late renal dysfunction following allogeneic bone marrow transplantation has been described by a number of centers including our own. Total body irradiation appears to play a major causative role in the development of this syndrome. In an effort to decrease the incidence of this renal toxicity we have added customized partial transmission renal blocking to our total body irradiation regimen. This partial renal shielding decreases the total dose to the kidneys from 14 Gy to 12 Gy. This report compares 71 adult patients who have received total body irradiation associated with bone marrow transplantation using renal shielding with 72 adult patients who were treated without the shielding; all of the patients have survived a minimum of 100 days post-BMT. Eighteen months following BMT, 26% of patients who did not have renal shielding have developed late renal dysfunction compared to only 6% of patients with renal shielding (p less than .05). Median follow-up in the nonblocked patients is 536 days post-transplant versus 341 days for the blocked patients. This added renal blocking has not adversely affected engraftment rates or relapse rates to date. Customized renal shielding as part of 14 gray total body irradiation in preparation for bone marrow transplantation appears to have decreased the incidence of late renal dysfunction in this group of adult patients and should be considered for all patients undergoing total body irradiation in conjunction with bone marrow transplantation.