Epidemiology of high-level parvovirus B19 viraemia among Dutch blood donors, 2003-2009.

BACKGROUND AND OBJECTIVES: Plasma derivatives and blood components with low levels of parvovirus B19 (B19) seem not infectious, but recently infected, highly viraemic donors may transmit B19. We studied the incidence of high-level B19 viraemia (B19 DNA>10(6) IU/ml) in 6.5 million Dutch blood donations. MATERIALS AND METHODS: Between 2003 and 2009, all Dutch blood and plasma donations were screened for the presence of B19 DNA, via pools of 480. Reactive pools were resolved and demographic parameters were obtained for all donors with B19 viraemia>10(6) IU/ml. In a subset, IgG and IgM antibodies to B19 were determined. RESULTS: Four hundred and eleven donations (1/15815) were identified with B19 DNA levels above 10(6) IU/ml, predominantly (83%) occurring in donors aged 18-47 years. Each year infection rates were elevated between December and July, with April accounting for 16% of infections. The years 2004 and 2009 were epidemic, with up to 1/4880 highly viraemic donations in May 2004. In a subset of 67 viraemic donations, 47/67 (70%) tested negative for IgG and IgM antibodies to B19; 16/67 (24%) showed isolated IgM and 4/67 (6%) contained IgG and IgM antibodies. The seasonal pattern of asymptomatic B19 infection in blood donors followed the notification rate of clinical cases. Geographically, B19 infection was randomly spread over the Netherlands. CONCLUSIONS: In epidemic seasons, blood donations with high levels of parvovirus, without concurrent antibodies, are common. They may infect immunocompromised and parvovirus-naïve recipients. The feasibility of preventive measures should be studied.

miRNA analysis in B-cell chronic lymphocytic leukaemia: proliferation centres characterized by low miR-150 and high BIC/miR-155 expression.

Several miRNAs have been reported to be associated with immunoglobulin heavy chain (IgH) mutation and ZAP-70 expression status in blood samples of B-cell chronic lymphocytic leukaemia/small lymphocytic lymphoma (B-CLL/SLL). In the bone marrow and lymphoid tissues, proliferation centres (PCs) represent an important site of activation and proliferation of the neoplastic cells, suggesting that these tissues better reflect the biology of CLL than circulating blood cells. We collected 33 lymph nodes and 37 blood CLL samples and analysed IgH mutation status and ZAP-70 expression status. Expression of 15 miRNAs was analysed by qRT-PCR and RNA-ISH. Sixty-three per cent of the lymph node cases contained mutated IgH genes and 49% of the lymph node cases were ZAP-70-positive, and a significant correlation was observed between ZAP-70 expression and IgH mutation status. Of the blood CLL samples, 49% contained mutated IgH sequences. The miRNA expression pattern in CLL lymph node and blood samples was very similar. Three of 15 miRNAs (miR-16, miR-21, and miR-150) showed a high expression level in both blood and lymph node samples. No difference was observed between ZAP-70-positive or -negative and between IgH-mutated or unmutated cases. No correlation was found between miR-15a and miR-16 expression levels and 13q14 deletion in the blood CLL samples. RNA in situ hybridization (ISH) revealed strong homogeneous staining of miR-150 in the tumour cells outside the PCs. In reverse BIC/pri-miR-155 expression was observed mainly in individual cells including prolymphocytes of the PCs. This reciprocal pattern likely reflects the different functions and targets of miR-150 and miR-155.

Autocrine growth and anchorage independence: two complementing Jun-controlled genetic programs of cellular transformation.

Cellular transformation can be achieved by constitutive activation of growth-regulatory signaling pathways, which, in turn, activate nuclear transcription factors thought to execute a transformation-specific program of gene expression. Members of the dimeric transcription factor family AP-1 are at the receiving end of such growth-regulating pathways and the viral form of the AP-1 subunit Jun establishes one important aspect of transformation in chick embryo fibroblasts (CEFs): enhanced growth in agar and in low serum. Enhanced Jun activity is likely to target several different genetic programs as Jun forms heterodimers with one of several members of the Fos and ATF2 subfamilies, resulting in transcription factors with different sequence specificities. To identify the programs relevant for transformation, we have reduced the complexity of AP-1 factors by constructing Jun bZip mutants that can efficiently dimerize and transactivate with only a restricted set of partner subunits. Upon introduction into CEFs, a Jun mutant selective for the Fos family induced anchorage-independent growth but no growth factor-independence. In contrast, a c-Jun mutant with preference for ATF2-like proteins caused growth factor-independence, but no growth in agar. Coexpression of both mutants reestablished the combined transformation program as induced by wild-type Jun. These data show that Jun-dependent cell transformation can be resolved into at least two distinct and independent processes, anchorage and growth factor independence, obviously triggered by two classes of Jun heterodimers likely regulating different sets of target genes.

EO9: a novel bioreductive alkylating indoloquinone with preferential solid tumour activity and lack of bone marrow toxicity in preclinical models.

EO9 is a novel and fully synthetic bioreductive alkylating indoloquinone. Although structurally-related to mitomycin C, EO9 exhibits a distinct preclinical antitumour profile and there are also differences in its biochemical activation. In this study, EO9 was found to demonstrate preferential cytotoxicity against solid tumours in vitro as compared to leukaemia cell lines both in the Corbett two-tumour assay and in the disease-oriented human tumour cell line panel of the U.S. National Cancer Institute. In the latter system activity was particularly apparent in colon, melanoma and central nervous system lines, together with some renal and non-small cell lung lines. Preferential cytotoxicity towards hypoxic versus aerobic EMT6 mouse mammary tumour cells was observed. In vivo, EO9 was inactive against the P388 murine leukaemia, while exerting significant antiproliferative effects against several murine and human solid tumours, including the generally resistant MAC mouse colon tumours and gastric, ovarian and breast xenografts. These results confirmed in vitro observations of preferential solid tumour activity. In animal toxicology studies, EO9 induced vascular congestion in the gastrointestinal tract, but no significant bone marrow toxicity. The LD10 value of EO9 after a single intravenous injection into mice was 9 mg/kg (27 mg/m2). A dose of one-tenth of the mouse equivalent LD10 (2.7 mg/m2), the recommended starting dose for clinical phase I studies, was found to be safe in rats. Considering its distinct mechanism of bioactivation as compared to mitomycin C, its preferential solid tumour activity, its excellent activity against hypoxic cells, and lack of significant bone marrow toxicity in animals studies, EO9 has been selected for clinical evaluation within the framework of the EORTC.

Pharmacokinetics, distribution, and metabolism of the novel bioreductive alkylating indoloquinone EO9 in rodents.

The indoloquinone EO9 is a novel and potent bioreductive agent related in structure to mitomycin C but differing in many aspects of its antitumor activity, toxicity, and enzymatic activation. Because it is about to undergo clinical trial, we have investigated the pharmacokinetics of EO9 in mice and rats. At the highest tolerated dose in male C3H/He mice (12 mg/kg iv) the initial plasma concentration (Co) was 1.8 micrograms/ml. The drug was cleared rapidly with a t1/2 of 1.9 min. The volume of distribution (Vd) was large (7.5 ml g-1) and the plasma clearance (Clp) correspondingly high (2.6 ml g-1 min-1). The AUCo-infinity was 4.8 micrograms ml-1 min. Equally rapid elimination was noted at the lower dose of 6 mg/kg iv. For comparison, the t1/2 for the same dose of mitomycin C was much longer at 16 min and the peak plasma level 4-fold higher. In male Sprague-Dawley rats receiving 3 mg kg-1 the Co was 1.5 micrograms/ml and the t1/2 was again short at 3.0 min. Vd was 2.2 ml g-1, Clp was 0.5 ml g-1 min-1, and AUCo-infinity was 6.2 micrograms ml-1 min. No parent drug was detected in urine, but extensive biotransformation was confirmed by the detection of around 20% of the dose as metabolites, including the aziridine ring-opened hydrolysis product EO5A. No drug or metabolite was detected in tumor or tissues. The results show that cytotoxic drug levels can be achieved for a short period in rodent plasma. The extremely fast excretion is consistent with the rapid rates of bioreductive metabolism in vitro. These data should be useful in the forthcoming clinical trials of EO9, where a pharmacokinetically guided dose escalation may be used, and also in the design and development of second generation analogues.

Toxicity of intrathecally administered cytotoxic drugs and their antitumor activity against an intrathecal Walker 256 carcinosarcoma model for meningeal carcinomatosis in the rat.

Meningeal carcinomatosis in humans is refractory to most attempts at therapy and has a grave prognosis. As part of a search for new agents to treat meningeal carcinomatosis, the toxicity of a series of antitumor agents administered through an implanted catheter directly into the cerebrospinal fluid (CSF) of the lumbar spinal cord of 200-g rats has been examined. The highest non-toxic dose (HNTD) of the agents producing no signs of histological damage, motor dysfunction, or neurobehavioral changes was bleomycin (80 micrograms), cytarabine (640 micrograms), dacarbazine (1 microgram), doxorubicin (20 micrograms), 5-fluorouracil (150 micrograms), methotrexate (1000 micrograms), mitomycin C (10 micrograms), and triethylene phosphoramide (800 micrograms). No toxicity was observed at the highest dose that could be administered because of limited solubility of 1,3-bis(2-chloroethyl)-1-nitrosourea (100 micrograms), or diaziquone (70 micrograms). The rat model gave reasonable prediction of the toxicity of antitumor agents that have been administered intra-CSF to humans but with a tendency to underpredict toxicity. The antitumor activity of the agents administered intra-CSF at the HNTD against a Walker 256 carcinosarcoma model for meningeal carcinomatosis in the rat was examined. Diaziquone, doxorubicin, methotrexate, and mitomycin C gave a 25% or greater increase in lifespan and diaziquone and mitomycin C gave some long-term survivors. BCNU, bleomycin and 5-fluorouracil gave less than a 25% increase in lifespan. When mitomycin C was administered intra-CSF at the HNTD and diaziquone at the limit of solubility daily for 4 days there was no toxicity and an increase in survival of Walker 256 carcinosarcoma tumored animals compared to animals administered a single daily dose. Intrathecal diaziquone was more active against meningeal Walker 256 carcinosarcoma than i.v. diaziquone. Intravenous methotrexate had no activity against meningeal Walker 256 carcinosarcoma. We conclude that intra-CSF administration of some anticancer agents such as diaziquone and mitomycin C at doses that do not produce toxicity can significantly increase the survival of rats with experimental meningeal carcinomatosis.

New xenograft model for assessing experimental therapy of central nervous system tumors: human glioblastoma in the intrathecal compartment of the nude mouse.

Ten congenitally athymic "nude" mice and 10 immunocompetent mice underwent intrathecal inoculation with a human glioblastoma cell line (U87MG) via percutaneous lumbar puncture (5 x 10(5) cells/animal). All of the nude mice developed paraplegia with or without incontinence at 2 weeks and routinely died of inanition 3 weeks postimplantation. Histological examination confirmed extensive proliferation of neoplastic cells within the intrathecal space. A second group of animals was inoculated with 5 x 10(4) cells/animal: 20 nude mice, 10 cyclosporine A-immunosuppressed animals, and 10 immunocompetent control mice. The 20 mice were further divided into four subsets. Subset A did not receive chemotherapy, Subset B received 200 mg of carmustine (BCNU) per m2 by intraperitoneal injection, Subset C received a single dose of 4 mg of methotrexate (MTX) per m2 by intrathecal injection 4 hours after tumor inoculation, and Subset D received 12 mg of intrathecal MTX per m2. Decreasing the concentration of cells per animal by 1 log doubled the time interval required for the development of paralysis and incontinence to 4 weeks. Treatment with intrathecal MTX at a dose of 4 mg/m2 extended the symptom-free period by an additional week (to 5 weeks postinoculation), and a dose of 12 mg/m2 allowed an average of 6 weeks before the onset of neurological impairment. The xenografts did not grow in the immunocompetent control mice, the BCNU-treated group, or the cyclosporine A-immunosuppressed animals. An intrathecal xenograft model of central nervous system malignancies allows a novel approach to the evaluation of experimental chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Activity of phthalocyanine photosensitizers against human glioblastoma in vitro.

In vitro studies utilizing an established human glioblastoma cell line (U87MG) were undertaken to compare the light absorption spectra and photocytotoxicity characteristics of hematoporphyrin derivative (HpD), metal-free phthalocyanine tetrasulfonate (PcS), and aluminum phthalocyanine tetrasulfonate (AlPcS). The peak absorption wavelengths for the compounds studied were: HpD = 630 nm, PcS = 630 nm, AlPcS = 677 nm. Seven different concentrations of each compound (0 to 20 micrograms/ml) were subjected to five different energy levels (40 to 640 joules/cm2) of broad band light (wavelength = 650 +/- 40 nm). Control experiments employing each drug alone and photoactivation alone were also performed. HpD showed a consistent dose-dependent photoactivated cytotoxicity with an abrupt decrease in cell survival when energies of 160 joules/cm2 or more were administered and a drug concentration dependency that resulted in a progressive decline in cell survival beginning at 1.0 microgram/ml. The metal-free PcS had a 10 times greater absorption of light at 675 nm, but only a very weak cytotoxic effect, which occurred at concentrations in excess of 10.0 micrograms/ml and energy levels greater than 320 joules/cm2. AlPcS, however, displayed a 100-fold increase in light absorption at 675 nm when compared to HpD. This was coupled with a decrease in cell survival similar to the HpD curves, but with a much steeper slope of percentage cell kill at lower drug concentrations and energy dosages. The control studies did not result in any appreciable cytotoxic effect. The data suggest that AlPcS holds promise as a second generation photosensitizer in the photodynamic treatment of human gliomas.

Effect of inhalation anesthetics on antipyrine pharmacokinetics of mice.

The effects of the volatile anesthetics, enflurane, isoflurane and halothane, on the pharmacokinetics of antipyrine were examined in mice. The administration of 0.75% isoflurane or 1.0% enflurane in air resulted in a 173 and a 206% increase, respectively, in antipyrine plasma half-life and a 29.1 and a 41.2% decrease in antipyrine total body clearance. There was also an almost 2-fold increase in the volume of distribution of antipyrine. Halothane, at 0.5% in air, had no significant effect upon antipyrine plasma half-life or its volume of distribution. There was no significant change in antipyrine total body clearance and volume of distribution 4 hr after exposure to the volatile agents, but there was a small increase in half-life. The exposures to the volatile anesthetics were also carried out in an atmosphere of 8% oxygen. Antipyrine plasma half-life was increased significantly by 48% in mice breathing 8% oxygen, compared to mice breathing air. Isoflurane in 8% oxygen increased the plasma half-life of antipyrine by 296% compared to mice breathing 8% oxygen. This increase was greater than the effect of isoflurane seen in mice breathing air. Mice breathing halothane in 8% oxygen exhibited a 21% increase in antipyrine plasma half-life and mice breathing enflurane in 8% oxygen, a 117% increase in antipyrine plasma half-life, although the changes were not markedly different from those seen in mice breathing air. Enflurane and isoflurane produced a significant increase in the volume of distribution for antipyrine in the mice breathing 8% oxygen. Total body clearance of antipyrine was decreased markedly in mice breathing isoflurane and enflurane but showed a lesser decrease in mice breathing halothane in 8% oxygen. In vitro in mouse microsomes, halothane, enflurane and isoflurane were all inhibitors of aminopyrine metabolism. Possible mechanisms for these results are discussed.

Doxorubicin-induced hair loss in the Angora rabbit: a study of treatments to protect against the hair loss.

An animal model for anticancer drug-induced hair loss has been developed using the Angora rabbit given i.v. doxorubicin, 2 mg/kg, twice weekly for 3 weeks. There was a 167% increase in the weight of hair collected by grooming between weeks 2 and 5, and a 72% inhibition of new hair growth at week 6 compared with non-treated animals. The hairs that grew in the doxorubicin treated rabbits did so at the same rate as in non-treated rabbits and appeared normal by light microscopy. Topical application of dimethylsulfoxide (DMSO), of 10% alpha-tocopherol in DMSO, of 0.5% naphthazoline hydrochloride in DMSO, of 0.1% fluocinolone acetonide in a propylene glycol base and local hypothermia did not provide any protection against doxorubicin-induced hair loss. Angora rabbits fed an alpha-tocopherol-deficient diet for 6 weeks showed decreased hair growth compared with animals fed a normal diet or a diet supplemented with 100 mg alpha-tocopherol acetate twice a week for 6 weeks. Some rabbits fed the alpha-tocopherol-deficient diet died when given doxorubicin. Rabbits fed the alpha-tocopherol-supplemented diet showed evidence of protection against doxorubicin-dependent inhibition of new hair growth.

Gas chromatographic assay for the new antitumor agent pyrazine-2-diazohydroxide (diazohydroxide) and its stability in buffer, blood and plasma.

Diazohydroxide is a new antitumor agent being considered for clinical trial. A sensitive and specific assay for diazohydroxide in physiological media, plasma and blood has been developed based on conversion of diazohydroxide to 2-chloropyrazine in the presence of strong hydrochloric acid. The 2-chloropyrazine is extracted into the ethyl acetate and separated by capillary gas chromatography with nitrogen-phosphorus detection. Using 0.2 ml plasma the assay was linear up to 100 micrograms/ml diazohydroxide and had a lower limit of detectability for diazohydroxide of 50 ng/ml. The coefficient of variation of the assay at 1 micrograms/ml was 6.7%. Breakdown of diazohydroxide was rapid under mild acid conditions but slower under alkaline conditions,. The half-life of diazohydroxide in 0.1 M sodium phosphate buffer, pH 6.0, at room temperature was 5 min and at pH 8.0, 480 min. Breakdown of diazohydroxide in plasma was biphasic. In fresh mouse plasma diazohydroxide had a terminal half-life at 37 degrees C of 72 min while in fresh human plasma the terminal half-life was 23 min and in fresh blood 21 min. Diazohydroxide accumulated in red blood cells at 37 degrees C to a concentration 68% above the concentration in plasma. Diazohydroxide was 49% bound to human plasma proteins at room temperature.

Increased toxicity of the antitumor drug cyclophosphamide in mice in the presence of the volatile anesthetic agent halothane.

Exposure of mice to 0.5% halothane in air, which is close to a maintenance concentration in man, after an IP dose of cyclophosphamide produced an increase in the lethality of cyclophosphamide. The LD50 (30 day) for cyclophosphamide without halothane was 251 mg/kg; with 2 h subsequent exposure to halothane it was 152 mg/kg; and with 20 h subsequent exposure to halothane it was 158 mg/kg. The median survival time of mice receiving cyclophosphamide at doses between 137 and 240 mg/kg was more than 30 days in the absence of halothane, 12 days with 2 h halothane, and 10.5 days with 20 h halothane exposure. Survival of mice was decreased irrespective of whether 2 h halothane exposure preceded or followed cyclophosphamide administration. Separation of cyclophosphamide administration and preexposure to halothane by breathing air for 1 h abolished the decrease in survival. Halothane exposure for 2 h after cyclophosphamide had no effect on the antitumor activity of cyclophosphamide. Total-body clearance of cyclophosphamide in mice exposed to halothane was 60 ml/min/kg, as against 188 ml/min/kg in nonexposed mice. No change was produced by halothane in the area under the plasma concentration-time curve over 2 h for 4-hydroxycyclophosphamide following cyclophosphamide administration. The reason for the increased lethality of cyclophosphamide in the presence of halothane could not be determined. There was no increase in leukopenia caused by cyclophosphamide and no increase in bladder toxicity, in liver toxicity, in renal toxicity, or in the penetration of cyclophosphamide into the brain. The study, together with reports of increased toxicity in patients receiving cancer chemotherapy in close proximity to general anesthesia, should alert physicians and others to the possibility of an interaction between volatile anesthetic agents and chemotherapeutic drugs.

Development of experimental models for meningeal neoplasia using intrathecal injection of 9L gliosarcoma and Walker 256 carcinosarcoma in the rat.

Two models for meningeal neoplasia have been developed in rats using intrathecal injection of 9L gliosarcoma and Walker 256 carcinosarcoma cells. Tumor cells were injected in unanesthetized animals through an indwelling catheter inserted at the cisterna magna to the level of the lumbar enlargement of the spinal cord. Survival of rats was dependent on the number of tumor cells injected. Spread of tumor was quantified by histology using a grading scale, and functional and behavioral changes were measured. Rats injected with 10(6) 9L gliosarcoma cells showed progressive weight loss, flaccid paralysis, and neurogenic bladder dysfunction and had a median survival of 11 days. The tumor frequently grew as a mass compressing the spinal cord. The 9L gliosarcoma tumor cells markedly invaded the Virchow-Robin spaces but exhibited only minimal invasion of the central nervous system parenchyma. The tumor reached the brain by day 10. Rats injected with 2 X 10(5) Walker 256 carcinosarcoma cells showed progressive weight loss and weakness and had a median survival of 6 days. The tumor grew within the leptomeninges in a discontinuous multifocal fashion and reached the brain by day 4. There was extensive invasion of the central nervous system parenchyma by Walker 256 tumor cells along the Virchow-Robin spaces resulting in hemorrhage and necrosis of grey and white matter. Hot plate and tail flick response times were significantly delayed only in the days immediately preceding death of animals with either 9L or Walker 256 tumor and were not good indicators of tumor progression. Loss of motor coordination and failure of the stepping and placing reflex on the other hand showed good correlation with spread of tumor measured histologically. Control animals injected with 0.9% NaCl or with lethally irradiated tumor cells showed no significant weight loss or functional or behavioral changes. The intrathecal 9L gliosarcoma and Walker 256 carcinosarcoma models show different characteristics of human meningeal carcinomatosis and will be used for studies of experimental chemotherapy with intrathecally administered antitumor drugs.

Activation and inactivation of cancer chemotherapeutic agents by rat hepatocytes cocultured with human tumor cell lines.

While colony formation assays provide sensitive indices of tumor cell proliferation and growth inhibition imposed by many chemotherapeutic agents, drugs which require metabolic activation lack activity in such assays. In the present study, we have utilized freshly isolated rat hepatocytes for the activation of drugs which are metabolized by hepatic microsomal as well as extra-microsomal enzymes. Hepatocytes in fluid medium are placed over soft-agarose matrix containing tumor-derived cells (e.g., A204, A549) within 35-mm culture dishes; drug and/or drug vehicle is added directly to the hepatocyte layer, and cultures are incubated for 24 hr prior to removal of the hepatocyte layer. Tumor cell colony formation is assessed following 7 to 10 days of incubation. Cyclophosphamide was used as a prototype agent to assess utility of the coculture methodology. In vivo treatment of rats with phenobarbital prior to hepatocyte isolation enhances cyclophosphamide toxicity in vitro, whereas pretreatment with carbon tetrachloride markedly reduced subsequent in vitro cyclophosphamide cytotoxicity. Hepatocyte:tumor cell cocultures provide an efficient means to detect metabolic activation and inactivation of several selected cancer chemotherapeutic agents as well. In the presence of hepatocytes, the 50% growth-inhibitory concentrations for cyclophosphamide, indicine N-oxide, and procarbazine are markedly decreased, whereas the 50% growth-inhibitory concentrations for [2,5-bis(1-aziridinyl)-3,6-diazo-1,4-cyclohexadiene-1,4-diyl]bis(c arbamic acid)diethyl ester, 1,3-bis-chloro(2-chloroethyl)-1-nitrosourea, dacarbazine, 5-fluorouracil, ftorafur, 1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea, and vincristine are significantly increased. By contrast, the 50% growth-inhibitory concentrations for actinomycin D, mitomycin C, 6-mercaptopurine, and other agents are unaffected by hepatocyte presence. Cryopreserved hepatocytes exhibit detectable levels of drug activation, although inadequate for routine use. Results suggest that hepatocyte:tumor cell cocultures may be well-suited for assessing the degree to which hepatic metabolism may activate or inactivate new anticancer drugs.

The specificity of nephritogenic antibodies: I. Evidence on anti-T-cell specificity in nephritogenic antibodies detected by cytotoxicity and MIF assays.

Heterologous antibodies directed to brushborder antigens of rat kidney tubules are nephritogenic in that an immediate immune complex glomerulopathy occurs after injection ot these antibodies into normal rats. Since previous observations suggested the presence of anti-T-cell specificity within these antibodies, we now compared the specificities of these antibodies with those of heterologous anti-rat thymocyte antibodies, using immunofluorescence (IF), cytotoxicity and migration inhibition (MIF) assays. The results suggest that anti-brushborder anti-serum contains anti-thymocyte specificities, while antithymocyte antiserum contains anti-brushborder specificity. These specificities could be removed selectively from both of the antisera by absorption with insoluble tissue extracts containing the appropriate antigens, i.e. thymocyte antigens or brushborder antigens respectively, indicating that two specificities are involved rather than only cross-reacting antibodies. Since it is unlikely for several other reasons that this feature is simply the result of an immunologic cross-reaction due to antibodies raised by immunization with purified kidney tissue antigens, this dual specificity of anti-brushborder antibody might play a role in the pathogenesis of experimental glomerulopathy.