Abstract P3-10-12: ERBB2 copy number analysis of invasive breast carcinoma using digital droplet PCR and targeted next-generation sequencing: A focus on 'non-classical' HER2 FISH groups using the 2018 ASCO/CAP HER2 testing guideline

Background: Non-classical HER2 FISH results were recently reclassified in the 2018 HER2 guidelines update, and concurrent IHC testing was recommended as part of additional workup to determine the final HER2 status in these groups. In this study, we explored the genomic landscape of HER2 FISH groups using digital droplet PCR (ddPCR) and targeted next-generation sequencing (NGS) on invasive breast carcinomas.

Methods: Fifty-one clinical samples with HER2 FISH and IHC results were included in our analysis and classified into FISH groups based on the updated 2018 ASCO/CAP HER2 testing guideline: (i) Group 1A with ratio ≥2 and signals/cell ≥6, (ii) Group 1B with ratio ≥2 and signals/cell ≥4 and <6, (iii) Group 2 with ratio ≥2 and signals/cell <4, (iv) Group 3 with ratio <2 and signals/cell ≥6, (v) Group 4 with ratio <2 and signals/cell ≥4 and <6, and (vi) Group 5 with ratio <2 and signals/cell <4. Formalin-fixed paraffin-embedded samples were analyzed using two ddPCR assays each targeting an exon in the ERBB2 tyrosine kinase domain (exon 19 and 21, respectively) and a 130-gene NGS-based assay. For ddPCR, ERBB2 amplification status was determined from ddPCR ratios by using a recently published algorithm (Otsuji et al. 2017). For targeted NGS, ERBB2 amplification was called when copy number gains were detected in the majority of exons in ERBB2 (>50% of exons).

Results: Mean ddPCR ratios varied amongst the different FISH groups (P < 0.0001). As expected, patients with Group 1A had the highest mean ddPCR ratios compared to those with other FISH findings (P < 0.0001). Furthermore, there was a correlation between ERBB2 ddPCR ratios and HER2 FISH ratios (ρe19 = 0.4435, P = 0.001 and ρe21 = 0.4644, P = 0.0006). Using ddPCR, ERBB2 amplifications were detected in all classically amplified Group 1A cases (5/5) and in none of the classically non-amplified Group 5 cases (0/12). Interestingly, ddPCR assays called ERBB2 amplification in four cases with non-classical results: one in Group 2 (1/6), two in Group 3 (2/6), and one in Group 4 (1/17), including two cases in Groups 3 and 4 which also showed concomitant HER2 overexpression by IHC (3+). Similarly, targeted NGS revealed ERBB2 amplification in all Group 1A cases (5/5) and in none of the Group 5 cases (0/12). Furthermore, NGS detected amplification in three non-classical cases: one in Group 1B (1/5), one in Group 3 (1/6), and one in Group 4 (1/17), including one case in Group 1B which was not called amplified by ddPCR. Notably, the three cases with amplification by NGS were the only three cases in the non-classical groups with HER2 overexpression by IHC. Overall, there was a strong concordance between ERBB2 amplification status by ddPCR/NGS and HER2 overexpression by IHC (κe19 = 0.79, κe21 = 0.92, κNGS = 1.0).

Conclusion: ERBB2 amplification using ddPCR and NGS is correlated with HER2 overexpression in both classical and non-classical FISH groups, thus providing genomic evidence to support the recent recommendation for concurrent IHC testing in cases with unusual FISH results. Our findings also highlight a potential role of ddPCR and targeted NGS in the workup of challenging HER2 cases.

Citation Format: Yang S-R, Bouhlal Y, De La Vega FM, Ballard M, West RB, Sibley RK, Kuo CJ, Vilborg A, Allison KH. ERBB2 copy number analysis of invasive breast carcinoma using digital droplet PCR and targeted next-generation sequencing: A focus on 'non-classical' HER2 FISH groups using the 2018 ASCO/CAP HER2 testing guideline [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-10-12.

Expression of insulin-like growth factor-I and transforming growth factor-beta in hypokalemic nephropathy in the rat

BACKGROUND

Potassium deficiency (KD) in the rat retards body growth but stimulates renal enlargement caused by cellular hypertrophy and hyperplasia, which is most marked in the outer medulla. If hypokalemia persists, interstitial infiltrates appear and eventually fibrosis. Since early in KD insulin-like growth factor-I (IGF-I) levels in the kidney are elevated, suggesting that it may be an early mediator of the exaggerated renal growth, and as transforming growth factor-beta (TGF-beta) promotes cellular hypertrophy and fibrosis, we examined the renal expression of these growth factors in prolonged KD.

METHODS

Rats were given a K-deficient diet or were pair fed or ad libitum fed a K-replete diet for 21 days. Growth factor mRNA levels were measured in whole kidney and protein expression localized by immunohistochemistry.

RESULTS

KD rats weighed less than pair-fed controls, while the kidneys were 49% larger. Their serum IGF-I and kidney IGF-I protein levels were depressed, as were their IGF-I mRNA levels in liver, kidney, and muscle. These changes can largely be attributed to decreased food intake. In contrast, kidney IGF binding protein-1 (IGFBP-1) mRNA and TGF-beta mRNA levels were increased significantly. Histology of outer medulla revealed marked hypertrophy and adenomatous hyperplasia of the collecting ducts and hypertrophy of the thick ascending limbs of Henle with cellular infiltrates in the interstitium. Both nephron segments immunostained strongly for IGF-I and IGFBP-1, but only the nonhyperplastic enlarged thick ascending Henle limb cells immunostained for TGF-beta, which was strongly positive. Prominent interstitial infiltrates with ED1 immunostained monocytes/macrophages were present.

CONCLUSIONS

These findings are consistent with a sustained role for IGF-I in promoting the exaggerated renal growth of KD and appear to be mediated through local trapping of IGF-I by the overexpressed IGFBP-1, which together with IGF-I can promote renal growth. The selective localization of TGF-beta to hypertrophied nonhyperplastic nephron segments containing IGF-I raises the possibility that TGF-beta may be serving to convert the mitogenic action of IGF-I into a hypertrophic response in these segments. It is also conceivable that TGF-beta may be a cause of the tubulointerstitial infiltrate. Finally, the low circulating IGF-I levels likely contribute to the impaired body growth.

Reduction of aortic wall motion inhibits hypertension-mediated experimental atherosclerosis

Hypertension is a well-known risk factor for coronary artery disease and carotid and lower extremity occlusive disease. Surgically induced hypertension in hypercholesterolemic animals results in increased aortic wall motion and increased plaque formation. We tested the hypothesis that reduction in aortic wall motion, despite continued hypertension, could reduce plaque formation. New Zealand White rabbits (n=26) underwent thoracic aortic banding to induce hypertension and were fed an atherogenic diet for 3 weeks. In 13 rabbits, a segment of aorta proximal to an aortic band was externally wrapped to reduce wall motion. All animals were fed an atherogenic diet for 3 weeks. Four groups were studied: 1, coarctation control (no wrap, n=7); 2, coarctation with loose wrap (n=6); 3, coarctation with firm wrap (n=7); and 4, control (noncoarcted, n=6). Wall motion, blood pressure, and pulse pressure were measured at standard reference sites proximal and distal to the coarctation by use of intravascular ultrasound. Quantitative morphometry was used to measure intimal plaque. Mean arterial pressure and cyclic aortic wall motion were equally increased proximal to the aortic coarctation in all 3 coarcted rabbit groups compared with the control group (P:<0.001). Wall motion in the segment of aorta under the loose and firm wraps was no different from the control value. The external wrap significantly reduced intimal thickening in the 4 groups by the following amounts: group 1, 0.30+/-0.03 mm(2); group 2, 0.06+/-0.02 mm(2); group 3, 0. 04+/-0.02 mm(2); and group 4, 0.01+/-0.01 mm(2) (P:<0.001). Localized inhibition of aortic wall motion in the lesion-prone hypertensive aorta resulted in significant reduction in intimal plaque formation. These data suggest that arterial wall cyclic motion may stimulate cellular proliferation and lipid uptake in experimental atherosclerosis.

Proliferating cell nuclear antigen as the cell cycle sensor for an HLA-derived peptide blocking T cell proliferation

Synthetic peptides corresponding to structural regions of HLA molecules are novel immunosuppressive agents. A peptide corresponding to residues 65-79 of the alpha-chain of HLA-DQA03011 (DQ65-79) blocks cell cycle progression from early G1 to the G1 restriction point, which inhibits cyclin-dependent kinase-2 activity and phosphorylation of the retinoblastoma protein. A yeast two-hybrid screen identified proliferating cell nuclear Ag (PCNA) as a cellular ligand for this peptide, whose interaction with PCNA was further confirmed by in vitro biochemistry. Electron microscopy demonstrates that the DQ65-79 peptide enters the cell and colocalizes with PCNA in the T cell nucleus in vivo. Binding of the DQ65-79 peptide to PCNA did not block polymerase delta (pol delta)-dependent DNA replication in vitro. These findings support a key role for PCNA as a sensor of cell cycle progression and reveal an unanticipated function for conserved regions of HLA molecules.

Comparison of chimeric acid and non-chimeric tolerance using posttransplant total lymphoid irradiation: cytokine expression and chronic rejection

BACKGROUND

Previous studies showed that an intravenous infusion of donor blood cells facilitates tolerance to ACI heart allografts in Lewis rat hosts given posttransplant total lymphoid irradiation (TLI) and anti-thymocyte globulin (ATG). The object of the current study was to compare tolerance induction using donor cells that do or do not induce chimerism.

METHODS

Normal peripheral blood mononuclear cells (PBMC), granulocyte colony-stimulating factor (G-CSF)-mobilized PBMC, and bone marrow (BM) cells from ACI donors were tested for their capacity to prolong ACI heart allograft survival in Lewis hosts. Chimerism, anti-donor cell reactivity, and cytokine gene expression in grafts were determined.

RESULTS

Intravenous injections of equal numbers of all three donor cells markedly prolonged graft survival (median: >164 to >175 days) as compared to uninjected controls (median: 53 days). Chimerism among T and B cells in the blood was determined by immunofluorescent staining in hosts bearing long-term (> 150 days) grafts. Although no chimerism was detected in hosts given normal or G-CSF-mobilized PBMC, chimerism was detected at variable levels in all hosts given BM cells. Vigorous anti-donor reactivity in the mixed leukocyte reaction was present only in non-chimeric hosts. Long-term grafts from hosts given normal ACI PBMC developed chronic rejection, but those from hosts given ACI BM cells did not. The latter hosts showed the lowest levels of intragraft cytokine mRNA.

CONCLUSIONS

Chimeric tolerance is more robust than non-chimeric tolerance in the model of posttransplant TLI, ATG, and donor cell infusion, and is associated with less chronic rejection.

The influence of combined trophic factors on the success of fetal pancreas grafts

BACKGROUND

Fetal pancreas (FP) has the capacity for abundant proliferation and beta cell differentiation. Insulin-like growth factor-1 (IGF-1) promotes FP engraftment in the i.m. site and reversal of diabetes in a rodent model. However, reversal of diabetes by an FP transplant in rats under the influence of IGF-1 is still an inefficient process requiring multiple FP grafts and a prolonged latent period. Numerous other growth and differentiation factors, which include platelet derived growth factor (PDGF), vascular endothelial growth factor, endothelial cell growth factor-alpha and pancreatic islet neogenesis-associated protein, have been implicated in beta cell neogenesis and proliferation. We have analyzed the in vivo role of these growth factors in FP engraftment and reversal of streptozotocin-induced diabetes in rats.

METHODS

IGF-1 alone or in combination with other trophic factors was locally administered to eight FP isografts in the thigh muscle of diabetic rats.

RESULTS

Diabetes was reversed in a mean of 60+/-26 days in 11 of 11 animals treated with IGF-1. PDGF alone did not promote reversal of diabetes; however, PDGF + IGF-1 resulted in euglycemia in 6 of 6, with a mean of 36+/-14 days (P<0.05). Islet neogenesis-associated protein +IGF-1 resulted in reversal of diabetes in 6 of 6 rats with a mean interval of 50+/-10 days. Vascular endothelial growth factor or endothelial cell growth factor-alpha + IGF-1 provided no advantage compared with IGF-1 alone.

CONCLUSIONS

These results demonstrate that IGF-1 is a potent trophic factor for transplanted FP and that PDGF acts synergistically with IGF-1 to promote reversal of diabetes by transplanting FP.

Monocyte-derived dendritic cell precursors facilitate tolerance to heart allografts after total lymphoid irradiation

BACKGROUND

Previous studies have shown that posttransplant total lymphoid irradiation, anti-thymocyte globulin, and an intravenous donor blood cell infusion induce tolerance to ACI heart allografts in Lewis rat hosts.

METHODS

In the current study, fresh ACI monocytes and dendritic cell precursors, derived from short-term culture of the latter cells in granulocyte macrophage colony-stimulating factor, were tested for their capacity to prolong heart allograft survival in this model.

RESULTS

The experimental results show that significant prolongation of graft survival was achieved after injection of the fresh donor monocytes or 2-day or 6-day cultured cells. The 2-day cultured cells were most effective, and more than 60% of hosts maintained graft survival for more than 160 days. Ten-day cultured cells and fresh splenic dendritic cells failed to prolong graft survival. Studies of cell surface markers showed that the 2-day cultured cells had up-regulated class II major histocompatibility complex and CD80, but not CD86 molecules. On the other hand, the 10-day cultured cells and splenic dendritic cells showed intense expression of all three markers. The latter cells stimulated vigorous proliferative and cell-mediated lympholysis responses in the mixed leukocyte reaction, but the fresh and 2-day cultured cells were weak stimulators.

CONCLUSION

The intravenous injection of donor dendritic cell precursors derived from blood monocytes facilitates long-term acceptance of heart allografts.

Donor blood monocytes but not T or B cells facilitate long-term allograft survival after total lymphoid irradiation

BACKGROUND

Previous studies showed that a combination of posttransplant total lymphoid irradiation (TLI), rabbit antithymocyte globulin (ATG), and a single donor blood transfusion induced tolerance to ACI heart allografts in Lewis rats. All three modalities were required to achieve tolerance. The objective of the current study was to determine the subset(s) of cells in the donor blood that facilitated long-term allograft survival.

METHODS

Lewis hosts received TLI, ATG, and donor cell infusion after heart transplantation. Graft survival, mixed leukocyte reaction (MLR), and intragraft cytokine mRNA were studied.

RESULTS

The intravenous injection of 25 x 10(6) ACI peripheral blood mononuclear cells (PBMC) significantly prolonged graft survival as compared with that of Lewis hosts given TLI and ATG alone. Injection of highly enriched blood T cells or splenic B cells adjusted for the number contained in 25 x 10(6) PBMC failed to induce significant graft prolongation. Unexpectedly, depletion of monocytes (CD11b+ cells) from PBMC resulted in the loss of graft prolongation activity. Enriched populations of monocytes obtained by plastic adherence were more efficient in prolonging graft survival than PBMC on a per cell basis. Hosts with long-term grafts (>100-day survival) showed evidence of immune deviation, because the MLR to ACI stimulator cells was vigorous, but secretion of interferon-gamma in the MLR was markedly reduced. In situ hybridization studies of long-term grafts showed markedly reduced levels of interferon-gamma mRNA as compared with rejecting grafts.

CONCLUSION

Infusion of donor monocytes facilitated graft prolongation via immune deviation.

Inducible nitric oxide synthase messenger RNA levels in hip periprosthetic tissue: a preliminary study

Nitric oxide (NO) is a ubiquitous molecule that has been associated with inflammation, arthritis, autoimmune disease, bone resorption, and other biological processes. Elucidating the role of NO at the bone-implant interface may further our understanding of the biological processes of osseointegration, loosening, and osteolysis. This study demonstrates the use of a molecular biological technique to investigate the possible role of NO in prosthetic loosening and periprosthetic bone resorption following total hip arthroplasty. Periprosthetic tissue from 12 patients undergoing revision hip arthroplasty was harvested and total ribonucleic acid (RNA) was extracted. In six of the 12 patients, multiple samples from different anatomic locations along the same interface were studied. To estimate the amount of NO present in the tissues in vivo, the level of inducible NO synthase (iNOS) messenger RNA (mRNA) was determined using a ribonuclease (RNase) protection assay. Inducible NOS mRNA was detected in every tissue sample: there was no correlation between iNOS mRNA levels and clinical loosening or osteolysis. Analysis of multiple tissue samples from the same prosthetic component revealed that the levels of iNOS mRNA vary greatly, confirming the heterogeneous nature of the interface.

RANTES chemokine expression in transplant-associated accelerated atherosclerosis

BACKGROUND

The pathogenesis of transplantation-associated accelerated atherosclerosis is poorly understood, but it is likely to be an alloimmune response involving infiltration of the vessel wall by T lymphocytes and monocytes leading to smooth muscle cell proliferation and extracellular matrix deposition. RANTES is a chemokine that selectively chemoattracts T lymphocytes, NK cells, monocytes, and eosinophils. The expression of RANTES in accelerated atherosclerosis was investigated by in situ hybridization and immunohistochemistry.

METHODS

Coronary arteries from six patients undergoing accelerated atherosclerosis were obtained at the time of retransplantation. Normal coronary arteries from two patients with idiopathic dilated cardiomyopathy were used as controls. Messenger RNA for RANTES was localized with digoxigenin-labeled complementary DNA probes. RANTES protein was detected by use of a monoclonal antibody and a three-step horseradish peroxidase method.

RESULTS

RANTES mRNA and protein were detected in the lymphocytes, macrophages, myofibroblasts, and endothelial cells of arteries undergoing accelerated atherosclerosis but not in normal coronary arteries.

CONCLUSIONS

In view of its in vitro biologic activity and in vivo expression pattern, RANTES may be a pivotal mediator of the cellular infiltrate seen in graft atherosclerosis. This information may help in the design of novel diagnostic and therapeutic approaches to this increasingly important disease process.

Coexistence of Th1- and Th2-type cytokine profiles in anti-CD2 monoclonal antibody-induced tolerance

Anti-CD2 monoclonal antibody OX34 has been shown to suppress immunity in rodents in vitro and in vivo. To evaluate the effects of OX34 on vascularized allografts, Lewis (RT1(1)) hearts were transplanted heterotopically into Wistar Furth (RT1(u)) rats. A single 5 mg/kg intraperitoneal dose of OX34 administered at transplantation induced indefinite graft survival (mean survival time >140.3+/-12.3 vs. 12.7+/-0.7 control, P=0.001). The mixed lymphocyte response was partially inhibited at 60 days after transplant, returning to normal at 100 days. Donor-specific tolerance was confirmed by acceptance of second donor (>100 days, n=2) and rejection of third-party (mean survival time: 7.5+/-0.5 days, n=2) hearts. Immunohistochemical staining of allograft tissue from tolerant animals demonstrated abundant CD2+, CD4+, and CD8+ graft-infiltrating cells. To elucidate further the nature of these cells, we compared the expression of interleukin (IL)-2, IL-4, IL-10, and interferon (IFN)-gamma mRNA in allografted tissue from tolerant, acutely rejecting (AR), isografted, and naive animals using nonisotopic in situ hybridization. A significant increase in IL-2, IL-4, IL-10, and IFN-gamma mRNA was observed in graft-infiltrating cells of both tolerant and AR animals. IL-10 mRNA expression 4 days after transplant was significantly elevated in the OX34-treated compared to AR recipients. These data demonstrate that a single dose of OX34 at engraftment induces tolerance to vascularized allografts. Expression of both T helper 1 and T helper 2 cytokine mRNA profiles (IL-2/IFN-gamma and IL-4/ IL-10, respectively) are up-regulated locally in graft-infiltrating cells of AR and tolerant animal allografts.

Parenchymal cytokine expression precedes clinically observed ischemia in dorsal flaps in the rat

Cytokines have been implicated as pivotal mediators of the wound-healing process. An understanding of the production and interaction of cytokines may lead to a better appreciation of the complex mechanisms of flap ischemia. The potential would then exist for novel diagnostic and therapeutic approaches to prevent and reverse damage to the endangered flap. The goal of this study was to determine the expression of parenchymal cytokines at various time points during flap ischemia. Punch biopsies were obtained from McFarlane dorsal flaps in the Sprague-Dawley murine model. We examined cytokine mRNA profiles for interleukin 1 alpha (IL-1 alpha), IL-2, IL-6, basic fibroblast growth factor (b-FGF), gamma-interferon (gamma IFN), transforming growth factor beta (TGF-beta), and platelet-derived growth factor A chain (PDGF-alpha) using in situ hybridization. Samples were taken from 0 to 48 hours postoperatively, with n = 3 for each time point. Eight hours postoperatively there was an abrupt peak of parenchymal cytokine expression at the bases of the flaps. Clinically at this time the flaps appeared completely viable without evidence of ischemic change. Leukocyte cytokine production peaked at 16 hours, when distal flap ischemia was evident clinically. These findings demonstrate an early peak of cytokine expression prior to clinical evidence of ischemia.

Mechanisms of tolerance to rat heart allografts using posttransplant TLI. Changes in cytokine expression

Lewis rats were rendered tolerant to ACI heart allografts using a regimen of posttransplant total lymphoid irradiation (TLI), rabbit antithymocyte or antilymphocyte globulin (RATG or RALG), and a single donor blood transfusion. All three treatment modalities were required to induce tolerance. The mechanism of the maintenance of tolerance was investigated by comparing the secretion of cytokines in the MLR, and the expression of cytokine mRNA in the allografts of tolerant and nontolerant Lewis rats. Although, the 3H-thymidine incorporation and secretion of IL-2 was frequently comparable in the MLR from tolerant and nontolerant rats, the secretion of IFN-gamma was markedly reduced in the tolerant rats. This was reflected in a markedly reduced frequency of cells expressing IFN-gamma mRNA in the allografts of tolerant as compared with nontolerant hosts. The frequency of cells expressing IL-2 and IL-10 mRNA was also reduced, but no significant difference was observed for cells with IL-4 mRNA. Spleen cells from nontolerant rats rapidly rejected ACI allografts in irradiated adoptive hosts, but spleen cells from tolerant rats did not. Evaluation of the cytokine mRNA expression at early and late time points in the allografts of adoptive hosts showed a pattern similar to that of the primary hosts. Thus, the tolerant state was associated with a maintenance or elevation of IL-4 expression and a marked reduction of IFN-gamma expression. Previous reports have shown that TLI alone induced this shift in the early recovery phase after irradiation.

Cardia allograft unresponsiveness using a posttransplant strategy : characterization of the graft infiltrate

We evaluated a combined posttransplant strategy using antilymphocyte serum (ALS) at time of engraftment followed by low dose total lymphoid irradiation (TLI) and donor bone marrow cell (BMC) inoculation administered either intrathymically (IT) or intravenously (IV) in the vigorously rejecting strain combination DA into Lew recipients. Allograft survival was significantly prolonged with administration of ALS in combination with TLI and IT (105 +/- 28.6 days) or IV (106.8 +/- 28.6 days) BMC compared to administration of ALS combined with either TLI (17.8 +/- 0.4 days) or BMC (9.0 +/- 0.0 days), or TLI combined with BMC (1 1.5 +/- 0.5 days) (P < 0.000 1, experimental vs control animals). There was no difference in survival between those animals who underwent IT or IV BMC inoculation. Third-party (WF) BMC inoculation did not significantly prolong allograft survival (10.0 +/- 1.0 days). A mild to moderate cellular infiltrate was present in allograft tissue after 100 days. To further characterize these cells, cytokine mRNA expression in allograft tissue (> 100 days posttransplant) was evaluated using nonisotopic in situ hybridization. A similar cytokine profile was demonstrated in allograft tissue compared to naive and isograft tissue, except for a slight increase in IL-2 (P < 0.02, control vs IV BMC; P = NS, other groups). In summary, unresponsiveness was induced in a high-responder strain combination using a combined posttransplant strategy of ALS, TLI, and donor antigen either IT or IV. The cytokine profile of the graft infiltrating cells was similar to that of normal tissue. Unresponsiveness may be the result of functional inactivation of these cells.

Differential localization of allograft nitric oxide synthesis: comparison of liver and heart transplantation in the rat model

Nitric oxide (NO) is a free radical with a diversity of cellular origins and potential functions. Within the realm of solid organ transplantation, NO has been the focus of much attention. Discordant reports have documented both suppression and potentiation of the alloimmune response. In addition to questions regarding its functional role, little is known of the cellular origins of NO in acute rejection of vascularized allografts. To address this question, acute rejection models of rat heterotopic heart and orthotopic liver transplantation were chosen. When compared with naive controls and isografted animals, acute rejection in both heart and liver transplantation was associated with elevated systemic levels of the NO metabolite, nitrite. This was accompanied by increased graft content of iNOS protein as determined by immunoblot analysis of protein extracts. Expression of iNOS mRNA was localized with in situ hybridization. In both heart and liver transplantation, iNOS mRNA was found in the inflammatory infiltrate accompanying acute rejection. In addition, hepatocytes also expressed iNOS mRNA in the rejecting liver allograft. In contrast, cardiac myocytes in the rejecting heart allograft did not stain for iNOS mRNA. These results indicate that organ-specific, differential cellular expression of iNOS occurs in the acutely rejecting allograft. Transcriptional regulation of iNOS may vary among various organs according to the local cellular milieu. In addition, there may be a variable allograft specific response to acute rejection which may modify the associated immunologic biology.

Hypertension-enhanced monocyte adhesion in experimental atherosclerosis

PURPOSE

Hypertension is a known clinical risk factor for atherosclerosis. In experimental atherosclerosis, monocyte adhesion to the endothelial surface is enhanced and is considered to be an important early stage in plaque formation. We tested the hypothesis that hypertension enhances monocyte adhesion in experimental atherosclerosis.

METHODS

Twenty-two New Zealand White rabbits were fed an atherogenic diet for 3 weeks to induce plaque formation. Aortic coarctation was created in eight rabbits by wrapping a Dacron band around the midportion of the descending thoracic aorta (stenosis group), whereas six rabbits underwent banding without aortic constriction (no stenosis group). Eight rabbits served as nonoperated controls. Monocyte binding to the aortic endothelial surface was counted with epifluorescent microscopy on standard aortic segments proximal and distal to the band. Immunohistochemistry was performed for the following antibodies: VCAM-1, RAM11, CD11b, and factor VIII.

RESULTS

Mean blood pressure was 89 +/- 3 mm Hg in the aorta proximal to the stenosis, compared with 64 +/- 4 mm Hg in the no stenosis group and 74 +/- 3 mm Hg in the control group (p < 0.01). The mean aortic blood pressure gradient across the stenosis was 16 +/- 2 mm Hg in the stenosis group, whereas the aortic blood pressure gradient was 0.2 +/- 0.6 mm Hg in the no stenosis group and -0.3 +/- 0.4 mm Hg in the control group (p < 0.001). Monocyte adhesion to the aortic endothelial surface proximal to the stenosis was increased twofold compared with adhesion to the aorta distal to the stenosis and compared with the proximal aorta in the control group (p < 0.02). The proximal-to-distal aortic ratio of monocyte binding was enhanced in the stenosis group (2.2) compared with the no stenosis (0.76) and control (0.83) groups (p < 0.01). The intima area of the aorta proximal to the stenosis was significantly increased compared with the proximal aortas in the no stenosis and control groups (p < 0.01). RAM11, CD11b, and endothelial VCAM-1 expression were enhanced in the hypertensive region proximal to the stenosis.

CONCLUSIONS

In the hypertensive region in the aorta proximal to the stenosis, monocyte adhesion and endothelial VCAM-1 expression were increased, with intimal thickening and accumulation of macrophages. These findings suggest that hypertension may promote atherosclerotic plaque formation by enhancing monocyte adhesion.

Mechanism of the antiproteinuric effect of cyclosporine in membranous nephropathy

Forty-one patients with a nephrotic syndrome and biopsy-proven membranous nephropathy were administered a 3 to 6-month course of cyclosporine (CsA;4 to 5 mg/kg per day). Differential solute clearances were used to evaluate glomerular function, before and after therapy. CsA lowered median proteinuria by 56%, from 7.3 to 3.2 g/24 h (P < 0.0001). Corresponding mean increments in serum albumin, immunoglobulin G, and oncotic pressure values were 31, 32, and 26%, respectively (all P < 0.0001). Arterial pressure, GFR, and renal plasma flow remained constant, but CsA restored the dextran-sieving curve toward normal, lowering the computed fraction of shunt-like pores by 25% (P < 0.05). In 14 instances, a cross-over design was used to randomly assign patients to 3 months of CsA versus 3 months of enalapril (10 to 30 mg daily), separated by a 1-month washout interval. Although enalapril lowered arterial pressure by 8 mm Hg (P < 0.01), it had no effect on proteinuria, plasma protein composition, filtration dynamics, or dextran sieving (all P = not significant). CsA dependence of proteinuria, indicated by relapsing nephrosis after CsA withdrawal, required additional courses of CsA to maintain proteinuria subnephrotic in most patients. In six patients with declining GFR during prolonged CsA treatment, a repeat biopsy showed more prominent immune deposits and a thicker glomerular basement membrane than at baseline. It was concluded that: (1) CsA lowers proteinuria in MN in part, by enhancing barrier size-selectivity; (2) lack of comparable efficacy of enalapril suggests that the antiproteinuric effect of CsA is related to its immuno-suppressive rather than glomerulodepressor properties; but (3) judged by repeat biopsy, CsA does not prevent continuing autoantibody formation in this disorder.

Cellular localization and effect of nitric oxide synthesis in a rat model of orthotopic liver transplantation

Nitric oxide (NO) is a multifunctional free radical with a variety of described biochemical and physiological roles. The immunologic relationships between organ transplantation and NO synthesis are unknown. While a number of in vitro and in vivo models have demonstrated an immunomodulatory role for NO, results suggest both an immunosuppressive and immunostimulatory function. In order to better delineate the role of NO in liver transplantation, the Kamada model of rat OLT with strain combinations simulating acute rejection and spontaneous hyporesponsiveness was chosen. In this setting, both acute rejection and spontaneous hyporesponsiveness were associated with increased levels of plasma NO metabolites and allograft expression of the enzyme, NO synthase (iNOS). The extent of expression was significantly greater with acute rejection. Using in situ hybridization, iNOS mRNA was localized to both infiltrating inflammatory cells and hepatocytes in the context of acute rejection. In contrast, iNOS mRNA expression was isolated to the hepatocytes in the hyporesponsive state. To specifically delineate the role of hepatocyte-derived NO, NO synthesis was ablated in the spontaneous hyporesponsiveness model and resulted in significant elevation of serum transaminase values with accompanying histologic evidence of increased periportal inflammatory infiltration. Our results suggest that the site of NO production varies according to the immunologic status of the liver allograft, and hepatocyte-derived NO may be protective in the hyporesponsive state.

RANTES chemokine expression in diseased and normal human tissues

RANTES is a member of a large family of cytokines, called chemokines, which are thought to play a regulatory role in inflammatory processes. We have made recombinant human RANTES protein which was used to generate a panel of anti-RANTES monoclonal antibodies. Following characterization, select anti-RANTES monoclonal antibodies were used for immunohistologic staining of a large panel of normal, diseased and fetal tissue sections. Diseased tissues included eleven lymphomas and eight renal tumors. Most tissues were also tested in parallel for RANTES mRNA by in situ hybridization using RANTES mRNA specific oligomeric probes. As expected, most normal adult tissues contain few, if any, RANTES positive cells. In contrast, RANTES expression dramatically increases in inflammatory sites. In addition, megakaryocytes, some tumours, and select fetal tissues express high levels of RANTES message and protein. These results indicate a wider expression of RANTES than previously appreciated and suggest multiple physiologic roles for this soluble factor.

Postischemic injury, delayed function and Na+/K(+)-ATPase distribution in the transplanted kidney

We evaluated the postischemic renal injury in 22 patients undergoing renal transplantation. Renal tissue obtained 45 to 60 minutes after reperfusion of the allograft was stained with specific antibodies against the delta subunit of Na+/K(+)-ATPase, fodrin and ankyrin. The distribution of each cytoskeletal protein was analyzed by laser confocal microscopy. Subsequent allograft function was assessed on two occasions, 1 to 3 and 36 hours post-reperfusion, respectively. Recipients were divided into two groups: those who achieved a normal GFR on post-transplant day 3 (group 1, N = 12) and those with persistent hypofiltration (group 2, N = 10). Patients of both groups exhibited impaired sodium reabsorption and isosthenuria one to three hours postoperatively, but these abnormalities persisted on day 3 only in group 2 subjects with persistent hypofiltration. Abnormalities of Na+/K(+)-ATPase, ankyrin and fodrin were confined to proximal tubule cells and were marked only in the subjects of group 2. They consisted of redistribution of each cytoskeletal protein from the basolateral membrane to the cytoplasm. We conclude that postischemic injury to a renal allograft results in a loss of polarity of proximal tubule cells. We propose that ensuing impairment of proximal sodium reabsorption could activate tubuloglomerular feedback, thereby contributing to the protracted hypofiltration that characterizes this form of postischemic, acute renal failure.

Interferon-gamma and interleukin-10 messenger RNA are up-regulated after orthotopic liver transplantation in tolerant rats: evidence for cytokine-mediated immune dysregulation

BACKGROUND

Immune regulation requires antigen recognition, signaling, activation, secretion of cytokines, and effector function by lymphocytes. Although there is redundancy in the activation and function of the immune response, some cytokines simultaneously promote and suppress different pathways of immunity. In the experiments reported here we compare cytokine gene expression within liver allografts from tolerant rats with normal and isografted liver tissue. We also compare the secretion of interferon-gamma (IFN-gamma) in the supernatant from mixed lymphocyte cultures by using peripheral blood lymphocytes stimulated against donor antigen.

METHODS

Orthotopic liver transplantations were performed using the cuff technique without hepatic artery revascularization. Nonisotopic in situ hybridization (ISH) was used to detect and localize messenger RNA to specific cells within tissue. Antisense DNA probes were generated to interleukin-2 (IL-2), IL-4, IL-10, and IFN-gamma. One-way mixed lymphocyte cultures were set up against irradiated donor splenocytes, and the supernatant was collected to measure IFN-gamma by enzyme-linked immunosorbent assay.

RESULTS

Expression of IFN-gamma and IL-10 was up-regulated in tolerant animals versus normal or isografted liver (p = 0.0002 and 0.0001, IFN-gamma and IL-10, respectively). In situ hybridization localized the expression of messenger RNA predominantly to the cytoplasm of the hepatocytes. Levels of IFN-gamma were higher in the supernatant from proliferating peripheral lymphocytes against donor antigen from tolerant animals versus naive control animals.

CONCLUSIONS

Expression of IFN-gamma and IL-10 is up-regulated in hepatocytes from allograft tissue after orthotopic liver transplantation. We believe that the up-regulation of IL-10 cross-regulates the effector function of IFN-gamma and supports cytokine-mediated immune dysregulation, which may be a mechanism of tolerance after orthotopic liver transplantation in rats.

Association of down-regulation of cytokine activity with rat hind limb allograft survival

Cytokines are short-acting protein modulators of many physiologic processes including graft rejection. An understanding of the production, action, and interaction of cytokines may lead to better appreciation of the complex mechanism of graft rejection. The potential would then exist for more selective and less-toxic means of modulating the immune response. A rat hind limb allograft model with major immunohistoincompatibility was used to study the local mRNA expression of IL-1 alpha, IL-2, IL-6, gamma interferon (gamma INF), platelet-derived growth factor-alpha (PDGF-alpha), basic fibroblast growth factor (FGF), and transforming growth factor-beta (TGF-beta) during acute allograft rejection. A 14-day postoperative course of immunosuppressive therapy with FK506 or rapamycin was administered. In situ hybridization was performed on serial full-thickness skin punch biopsies of the untreated rejecting limb allograft and compared with tissue from treated allografts, isografts, and to normal limb tissue. A sequential pattern of cytokine mRNA expression was demonstrated which progressed in a time-dependent manner and paralleled observed clinical rejection. Maximal cytokine mRNA expression correlated with peak graft rejection. Cellular expression of IL-1 alpha, IL-2, IL-6, gamma-INF, FGF, and TGF-beta mRNA was suppressed with FK506 to below isograft levels, and clinical rejection was not observed with the doses, routes, and schedules used. Rapamycin was ineffective in suppressing cytokine expression, and allograft rejection was not prevented. Isografts demonstrated no evidence of rejection. The in situ hybridization technique demonstrates a time-dependent, selective expression of cytokines within rejecting allograft tissue, and the modification of this response with immunosuppressive therapy. Down-regulation of cytokine expression is associated with clinical allograft survival.

Intravenous methylprednisolone and oral alkylating agent therapy of prednisone-resistant pediatric focal segmental glomerulosclerosis: a long-term follow-up

Prednisone-resistant nephrotic syndrome (NS) due to focal segmental glomerulosclerosis (FSGS), the most common acquired disease requiring chronic dialysis and transplantation in children, has a low likelihood of response to alkylating agent therapy. This report summarizes the results of a 0.75-12.5 (average 6.33) year follow-up of 32 pediatric cases of prednisone-resistant FSGS treated with a regimen of high-dose intravenous methylprednisolone (M-P) and alternate-day prednisone, plus an alkylating agent in 25/32. On last followup: 21/32 were in remission [urine protein-to-creatinine ratios (Pru/Cru) < or = 0.2]; 3/32 had mild proteinuria (Pru/Cru > 0.2-0.5); 2/32 had moderate proteinuria (Pru/Cru > 0.5-1.9); and 6/32 remained nephrotic (Pru/Cru > or = 2.0). Of the incomplete or nonresponders; 3/11 progressed to end-stage renal failure; 5/11 had decreased creatinine clearances (CrCl): and 3/11 had persistent proteinuria with normal CrCl. All of the persistently nephrotic children, but none of the complete responders, developed decreased CrCl. All of the complete responders were able to stop treatment; four relapsed but responded well to retreatment.

CONCLUSIONS

This regimen of methylprednisolone and alternate-day prednisone, with or without an alkylating agent, is effective in achieving sustained remissions and preserving normal renal function in the great majority of children with FSGS and prednisone-resistant NS.

Mechanisms of filtration failure during postischemic injury of the human kidney. A study of the reperfused renal allograft

Postischemic filtration failure in experimental animals results primarily from depression of the transcapillary hydraulic pressure difference (delta P), a quantity that cannot be determined in humans. To circumvent this limitation we determined the GFR and each of its remaining determinants in transplanted kidneys. Findings in 12 allografts that exhibited subsequent normofiltration (group 1) were compared with those in 11 allografts that exhibited persistent hypofiltration (group 2). Determinations were made intraoperatively in the exposed graft after 1-3 h of reperfusion. GFR (6 +/- 2 vs 29 +/- 5 ml/min) and renal plasma flow by Doppler flow meter (140 +/- 30 vs 315 +/- 49 ml/min) were significantly lower in group 2 than group 1. Morphometric analysis of glomeruli obtained by biopsy and a structural hydrodynamic model of viscous flow revealed the glomerular ultrafiltration coefficient to be similar, averaging 3.5 +/- 0.6 and 3.1 +/- 0.2 ml/(min.mmHg) in group 2 vs 1, respectively. Corresponding values for plasma oncotic pressure were also similar, averaging 19 +/- 1 vs 21 +/- 1 mmHg. We next used a mathematical model of glomerular ultrafiltration and a sensitivity analysis to calculate the prevailing range for delta P from the foregoing measured quantities. This revealed delta P to vary from only 20-21 mmHg in group 2 vs 34-45 mmHg in group 1 (P < 0.001). Further morphometric analysis revealed the diameters of Bowman's space and tubular lumens, as well as the percentage of tubular cells that were necrotic or devoid of brush border, to be similar in the two groups. We thus conclude (a) that delta P depression is the predominant cause of hypofiltration in this form of postischemic injury; and (b) that afferent vasoconstriction rather than tubular obstruction is the proximate cause of the delta P depression.

Virus-associated hemophagocytic syndrome characterized by clonal Epstein-Barr virus genome

Virus-associated hemophagocytic syndromes are a heterogeneous group of disorders in which viral infection is associated with a proliferation of hemophagocytic histiocytes throughout the reticuloendothelial system. The authors report the case of a 24-year-old Vietnamese male who developed a hemophagocytic syndrome associated with Epstein-Barr virus (EBV) and who died following a rapidly progressive course. A proliferation of reactive-appearing lymphoid cells was associated with an extensive proliferation of erythrophagocytic histiocytes. Immunophenotypically, the lymphoid infiltrate consisted of CD56+ natural killer cells, predominantly CD8+ T-cells and rare B-cells (CD20+). Double-label immunohistochemical studies showed CD3+ T-cells and CD56+ natural killer cells to be distinct cell populations. Combined immunohistochemical-in situ hybridization studies localized EBV to CD43+, CD3-, CD68-, lymphoid-appearing cells, indicating the presence of EBV within natural killer cells. Southern hybridization analysis of EBV genomic termini revealed clonal EBV genome. However, there was no detectable immunoglobulin or T-cell receptor gene rearrangements. The findings indicate that this case of hemophagocytic syndrome represents a clonal proliferation of natural killer cells containing EBV and highlights the importance of the analysis of EBV genomic termini for determination of clonality in EBV-associated proliferations. It is possible that other cases of fulminant EBV-associated hemophagocytic syndromes represent clonal natural killer cell proliferations.

Light microscopic and immunohistochemical features in serial biopsies of epidermal versus dermal allografts

The local immune response to allograft dermis and epidermis was studied in a rat skin-graft model. Biopsies taken at varying times after transplantation were analyzed using routine light microscopy and a panel of monoclonal antibodies. The dermis appeared to be spared by the rejection process, whereas the epithelium and adnexal elements of the dermis were destroyed. The persistence of dermis transplanted across major histoincompatibilities may allow it to be useful in reconstructing large skin losses.

Congenital unilateral hydronephrosis in a rat model: continuous renal pelvic and bladder pressures

We investigated a rat model with inbred unilateral congenital hydronephrosis. Simultaneous bladder and renal pelvic pressures were measured during different urinary flows, and during bladder filling and voiding in these congenitally hydronephrotic rats (approximately 45 days old) and normal nonhydronephrotic rats from the same colony. Differential pressures between pelvis and proximal ureter were determined. Upon termination of the experiment the urinary tract was removed and processed for histological examination. Hydronephrotic rats had significantly higher renal pelvic pressures throughout bladder filling at all urinary flow rates than normal rats. These elevated renal pelvic pressures exceeded bladder pressures at high flows (for example bladder pressure at 50% capacity was 8.9 +/- 3.1 cm. water and corresponding pelvic pressure was 20.8 +/- 2.1 [hydronephrosis] versus pelvic pressure 7.4 +/- 1.1 [control]). While pressures in the proximal ureter were higher than in the pelvis in normal rats the hydronephrotic rats showed significantly higher pressures in the pelvis, suggesting that the site of obstruction is the ureteropelvic junction. Histological evaluation of the excised kidneys revealed only minimal tubular changes. This study represents a unique animal model with unilateral hydronephrosis from a partially obstructing ureteropelvic junction. Moreover, the data indicate that partial urinary obstruction and the associated renal pelvic pressures should be defined with reference to bladder fullness and urinary flow rates.

Morphologic features of chronic rejection in kidney and less commonly transplanted organs

Chronic rejection is characterized by morphological evidence of destruction of the transplanted organ. The injury to the organ is associated with collagenization of variable degree. The destruction and fibrosis of the organ is probably the result of 1) direct alloimmune cytotoxic injury (i.e., acute and/or ongoing rejection) of the organ tissue, and 2) end-organ ischemic injury secondary to fibroproliferative endarteritis (i.e., chronic vascular rejection). The cardinal morphological feature of chronic rejection in all allografts is fibroproliferative endarteritis, which is characterized by widening of the subendothelial space due to a cellular fibrosis which may have an onion-skin appearance with a PAS or silver stain. Macrophages with foamy cytoplasm and lymphocytes may be present in this fibrotic tissue. The smooth muscle wall may show foci of fibrosis as well, if involved by previous necrotizing rejection. These features are commonly found in needle core biopsies of kidney allografts and may involve the interlobular, arcuate, and interlobar arteries. They are less commonly found in pancreatic needle biopsies, and only rarely in hepatic and pulmonary allograft biopsies, rendering the diagnosis of chronic rejection often difficult to establish. Though the vascular lesions may not be apparent in biopsies, they are typically found in explanted organs where larger vessels can be examined. Thus, the diagnosis of chronic rejection may rest upon other and in some instances less specific abnormalities, usually ischemic in origin due to vascular lesions and consequent decreased perfusion of the graft.(ABSTRACT TRUNCATED AT 250 WORDS)

RANTES chemokine expression in cell-mediated transplant rejection of the kidney

RANTES (regulated upon activation, normal T cell expressed and secreted) is a chemotactic cytokine (a chemokine) for memory T lymphocytes, monocytes, and eosinophils. RANTES expression was studied in renal allograft biopsy specimens. Although RANTES was not expressed in samples taken one hour after transplantation, or in native renal biopsy specimens from patients with cyclosporin nephrotoxicity, it was expressed during cell-mediated transplant rejection. RANTES mRNA was detected in infiltrating mononuclear cells and renal tubular epithelium, and RANTES protein was localised to mononuclear cells, tubular epithelium, and vascular endothelium. This suggests RANTES has a role in allograft rejection.

Cyclosporin A nephropathy: standardization of the evaluation of kidney biopsies

An advisory board of nephropathologists with personal experience in the evaluation of biopsies from patients treated with cyclosporin A (CyA) was set up to address the following problems: 1. Definition of CyA nephropathy as seen in patients with autoimmune diseases; 2. Evaluation of the reliability and reproducibility of the diagnostic criteria for the different morphological lesions seen in CyA nephropathy; 3. Classification of the morphological lesions according to their clinical relevance; 4. Estimation of the possible progression of CyA nephropathy with continuous CyA therapy. The most frequent lesions attributable to CyA therapy in patients with autoimmune diseases are tubular atrophy, interstitial fibrosis, and arteriolar hyalinosis. All other lesions are rare. The reproducibility and diagnostic reliability is high for tubular atrophy and interstitial fibrosis, but low for arteriolar lesions even among experienced nephropathologists. The biopsies may be classified according to the severity of tubular atrophy, interstitial fibrosis and arteriolar hyalinosis with regard to their clinical relevance: In group I (within normal limits), CyA therapy can be continued; in group III (moderate-to-severe CyA-related lesions), CyA should be stopped if possible. Among group II biopsies (slight CyA-related abnormalities), no recommendation can be made in the absence of a second biopsy after a further year of CyA therapy. No clear-cut answer can be given concerning the progression of CyA-induced lesions. However, no significant progression has been found in the cases studied to date.

Monocyte haptotaxis induced by the RANTES chemokine

BACKGROUND

Soluble mediators and inducible cell-surface molecules coordinate the ordered cascade of events giving rise to inflammation. The specific mechanisms underlying the attraction of antigen-specific cells into a site of inflammation remain sketchy, however. In particular, it is unclear how chemoattractants cause rapidly moving immune cells to adhere to the blood vessel wall and to enter inflamed tissues.

RESULTS

Here we show that RANTES, a potent chemo-attractant for monocytes and T lymphocytes, is inducibly expressed within an inflamed organ, binds to endothelial cells, and promotes haptotaxis, the migration of cells induced by surface-bound gradients.

CONCLUSION

These findings lead us to propose a model for the role of RANTES in the migration of antigen-specific immune cells into an inflammatory site.

Adenine phosphoribosyltransferase deficiency with renal deposition of 2,8-dihydroxyadenine leading to nephrolithiasis and chronic renal failure

Homozygous adenine phosphoribosyltransferase deficiency is a genetic defect that is associated with 2,8-dihydroxyadenine urolithiasis. Since the prevalence of the heterozygous state is found in 0.4% to 1.2% of the population, it is surprising that more cases of 2,8-dihydroxyadenine urolithiasis have not been reported. Herein we describe a patient with complete adenine phosphoribosyltransferase deficiency with 2,8-dihydroxyadenine urolithiasis leading to chronic renal failure. Gene sequencing revealed that the patient is a compound heterozygote. One of the mutations (a T insertion between bases 346 and 347) has been encountered before, but the second (a G-to-A substitution at base 1356) has not been previously reported. Possible explanations for the unexpected rarity of 2,8-dihydroxyadenine urolithiasis are discussed.

The role of transbronchial biopsies in the management of lung transplant recipients

We examined the utility of the transbronchial biopsy in the management of 53 lung transplant patients. One hundred thirty-three protocol biopsies were performed to ascertain the frequency and nature of abnormalities in clinically stable or asymptomatic patients; 128 diagnostic biopsies were performed in clinically ill patients to assess the morphologic abnormalities before the institution of therapy, and 105 biopsies were performed to assess the response to therapy. Histologic evidence of acute rejection was found in 24% of the protocol biopsies, and infection was found in 17%. Twenty-five patients with grade 1 or grade 2 perivascular infiltrates in protocol biopsies did not receive antirejection therapy. Follow-up biopsy in these patients showed spontaneous resolution of the infiltrates in 19% and increased infiltrates in 6. Only two of these patients became clinically ill, representing "progression" to clinical rejection in only 8% of the nontreated patients. Forty percent of the biopsies performed to rule out acute rejection or infection had histologic features of acute rejection, and another 23% had features of infection. Treatment of patients with clinical and histologic evidence of rejection was associated with rapid resolution of clinical symptoms in nearly 90% of the patients, but follow-up biopsies showed residual infiltrates compatible with ongoing or resolving rejection in 52%. Despite repeat antirejection therapy in some patients, these infiltrates persisted for an average of 30 days after the diagnostic biopsy. Follow-up biopsies also showed asymptomatic infection, usually cytomegalovirus pneumonitis, which often persisted for weeks despite the lack of symptoms. Perivascular infiltrates compatible with acute rejection were also found in 38% of biopsy specimens with evidence of infection. These perivascular infiltrates resolved with antibiotic treatment alone in nearly 50% of the patients with these features. Although perivascular mononuclear cell infiltrates are the cardinal histologic feature of acute rejection, similar infiltrates occur in patients who apparently have infection alone and other patients who have both infection and rejection; infiltrates compatible with minimal, mild, and moderate acute rejection also occur in clinically asymptomatic patients. These histologic findings are a challenge to both the pathologists' and the clinicians' skills in the management of the lung transplant patient.

Topographical dissociation of BCL-2 messenger RNA and protein expression in human lymphoid tissues

Immunohistochemistry and in situ hybridization with a synthetic oligonucleotide probe were used to compare the topographical distribution of BCL-2 proto-oncogenic protein with that of its messenger RNA (mRNA) in normal lymphoid tissues, follicular lymphomas, and lymphoma-derived cell lines. In normal lymph nodes, BCL-2 protein was most abundant in the small lymphocytes of primary lymphoid follicles and the mantle zones of secondary follicles, virtually absent within germinal centers, and of variable abundance in many interfollicular cells. In contrast, the distribution of BCL-2 mRNA was roughly reciprocal to that of the protein with intense hybridization signal in germinal centers and almost none in mantle zones. Discordant BCL-2 RNA and protein levels were also observed in tonsillar epithelial cells and cortical thymocytes. Concordant and abundant expression of BCL-2 mRNA and protein was detected in biopsy tissues and cell lines from t(14;18)-carrying lymphomas. The contrasting distributions of BCL-2 protein and RNA in normal lymphoid tissues suggest that translational and posttranslational control mechanisms play a significant role in regulating BCL-2 protein levels in germinal center cells, epithelial cells, and cortical thymocytes. Concordant BCL-2 mRNA and protein levels in follicular lymphomas suggest that translational control mechanisms may be disrupted as part of the sequence of genetic changes that transforms normal lymphoid cells into neoplastic follicular lymphoma cells.

Extent and course of glomerular injury in human membranous glomerulopathy

Glomerular permselectivity and dynamics were evaluated serially in 14 nephrotic patients with membranous glomerulopathy (MG). Analysis of transglomerular dextran sieving, before and again after proteinuria remitted, revealed persistent depression by 60-80% of glomerular pore density and the two-kidney ultrafiltration coefficient, Kf. The glomerular filtration rate was lowered by half on each occasion. Morphometric examination of glomeruli in a second group of 16 nephrotic patients with MG revealed a low prevalence of glomerulosclerosis (5 +/- 3%) and a twofold increase in filtration surface due to marked glomerular hypertrophy. Presumably, widening by threefold of the basement membrane and/or epithelial podocytes accounted for the computed reduction in ultrafiltration capacity. There was no correlation between glomerular structure and the subsequent course of MG over the ensuing 24-96 mo. Rather, a twofold expansion of the interstitial compartment predicted those who went on to exhibit progressive renal insufficiency. We conclude that increasing resistance to water flow by walls of patent and perfused glomerular capillaries is the proximate cause of progressive renal insufficiency in MG.

Renal insufficiency secondary to 2,8-dihydroxyadenine urolithiasis

A 48-year-old man with a history of recurrent urolithiasis and chronic renal failure underwent a nephrectomy for a renal mass. At surgery the mass proved to be a calculus impacted in a dilated calyx. Gross examination of the kidney revealed chalky white deposits in the deep medulla and papillary tips. Histologic examination revealed chronic interstitial nephritis with brown spicules within some tubular epithelial cells and larger deposits of brown crystals within tubular lumina, the interstitium of the medulla, and papillary tips. Polarization microscopy revealed individual crystals scattered throughout the renal parenchyma. Although the arrangement of the crystals was reminiscent of uric acid, and, in fact, a clinical diagnosis of gouty nephropathy was made, x-ray diffraction analysis demonstrated crystals of 2,8-dihydroxyadenine. Enzymatic studies confirmed the complete absence of adenine phosphoribosyltransferase activity in erythrocyte lysates.

Microvillous inclusion disease. The importance of electron microscopy for diagnosis

We report two cases of microvillous inclusion disease (MID) occurring in a set of siblings. Although it is a rare disorder, MID appears to be a common cause of familial intractable secretory diarrhea. Diagnosis rests on the ultrastructural finding of intracytoplasmic inclusions that are lined by intact microvilli. These inclusions are present in the absorptive surface epithelial cells of the small and large intestine and are associated with poorly developed surface brush border microvilli. The prognosis of MID is poor and curative therapy is not currently available. Because MID appears to be a hereditary disorder, genetic counseling of affected families is essential.

Helicobacter pylori infection and the risk of gastric carcinoma

BACKGROUND

Infection with Helicobacter pylori has been linked with chronic atrophic gastritis, an inflammatory precursor of gastric adenocarcinoma. In a nested case-control study, we explored whether H. pylori infection increases the risk of gastric carcinoma.

METHODS

From a cohort of 128,992 persons followed since the mid-1960s at a health maintenance organization, 186 patients with gastric carcinoma were selected as case patients and were matched according to age, sex, and race with 186 control subjects without gastric carcinoma. Stored serum samples collected during the 1960s were tested for IgG antibodies to H. pylori by enzyme-linked immunosorbent assay. Data on cigarette use, blood group, ulcer disease, and gastric surgery were obtained from questionnaires administered at enrollment. Tissue sections and pathology reports were reviewed to confirm the histologic results.

RESULTS

The mean time between serum collection and the diagnosis of gastric carcinoma was 14.2 years. Of the 109 patients with confirmed gastric adenocarcinoma (excluding tumors of the gastroesophageal junction), 84 percent had been infected previously with H. pylori, as compared with 61 percent of the matched control subjects (odds ratio, 3.6; 95 percent confidence interval, 1.8 to 7.3). Tumors of the gastroesophageal junction were not linked to H. pylori infection, nor were tumors in the gastric cardia. H. pylori was a particularly strong risk factor for stomach cancer in women (odds ratio, 18) and blacks (odds ratio, 9). A history of gastric surgery was independently associated with the development of cancer (odds ratio, 17; P = 0.03), but a history of peptic ulcer disease was negatively associated with subsequent gastric carcinoma (odds ratio, 0.2; P = 0.02). Neither blood group nor smoking history affected risk.

CONCLUSIONS

Infection with H. pylori is associated with an increased risk of gastric adenocarcinoma and may be a cofactor in the pathogenesis of this malignant condition.

Glomerular dysfunction in nephrotic humans with minimal changes or focal glomerulosclerosis

Fractional clearances (theta) of uncharged dextrans (radii 28-60 A) were used to characterize glomerular dysfunction in 34 nephrotic humans with either minimal-change nephropathy (MCN) or focal, segmental glomerulosclerosis (FSGS). A theoretical analysis of theta of dextran with a heteroporous membrane model revealed a similar alteration, more marked in FSGS than MCN. The number of restrictive pores perforating the major membrane component was reduced in parallel with the prevailing glomerular filtration rate (GFR). Parallel shuntlike pores in the remaining membrane component were more prominent, pointing to impaired size selectivity. However, the theta of large (60 A) dextrans attributable to these shunts exceeded control in FSGS only, suggesting that coexistent impairment of charge selectivity contributed importantly to the proteinuria in MCN. Membrane properties returned toward normal when MCN remitted. Glomerular morphometry revealed the frequency of epithelial filtration slits to vary with the extent of membrane dysfunction. Despite offsetting hypertrophy of remnant glomeruli in FSGS, a loss of filtration surface due to sclerosis likely contributed to the more marked reductions in pore number and GFR observed in this disorder than in MCN.

Helicobacter pylori infection in intestinal- and diffuse-type gastric adenocarcinomas

Gastric cancer can be divided into two histologic types: intestinal and diffuse. To determine whether Helicobacter pylori, a bacterium linked with gastritis, was associated with either cancer type, we reviewed histologic sections from stomachs of patients who had undergone gastrectomy for gastric cancer. Of 37 of the sections with evidence of intestinal-type cancer, 33 (89.2%) contained H pylori in noncancerous tissue compared with 7 (31.8%) of 22 of the sections with evidence of diffuse-type cancer (odds ratio = 17.7; P less than .001). This association remained strong when controlled for age, sex, site, and number of sections reviewed. The prevalence of H pylori in intestinal-type gastric cancer far exceeded the prevalence of H pylori in diffuse disease and that described in the normal US population. This finding suggests that H pylori may be a cofactor in development of intestinal-type gastric cancer.

Extent of glomerular injury in active and resolving lupus nephritis: a theoretical analysis

Patients with diffuse, proliferative lupus nephritis (DPLN) were subjected to differential solute clearances (n = 22) and serial renal biopsy (n = 11) before and again after 6-12 mo of immunosuppressive therapy. Glomerular sieving of dextrans of graded size was analyzed with a heteroporous membrane model. This revealed active DPLN to be associated with 1) a reduction of overall pore density accompanied by a 53% depression of glomerular filtration rate (GFR), and 2) appearance of a subset of large, nondiscriminatory pores, which accounted for the observed nephrotic level of proteinuria. Morphometric analysis of biopsy tissue provided evidence of reduced filtration surface area due to global or segmental occlusion of capillary loops in glomerular tufts. Activity of DPLN resolved posttreatment. A computed increase in pore density was associated with a 24% increment in GFR; a marked reduction in the fraction of shuntlike pores was accompanied by a parallel reduction of proteinuria into a subnephrotic range. Repeat biopsy revealed diminished glomerular cellularity, fewer immune deposits, and an ensuing increase in the fraction of tuft area occupied by patent loops. Epithelial filtration slit frequency also increased. Neither functional nor structural recovery was complete, however. Residual pore density approximated only 23-35% of that in healthy controls, and corresponding shuntlike pores were threefold more prominent. We conclude that severe DPLN is only partially reversible by current modalities of treatment and that the ensuing residual injury is far more severe than suggested by conventional tests of renal function.

Post-transplantation outcome of patients with hemolytic-uremic syndrome: update

The outcome of renal transplantation in patients with hemolytic-uremic syndrome (HUS) is variable in reported cases. An update of the previously published series of patients from the University of Minnesota is reported. Seventeen patients with HUS received a renal transplant. Seven patients had recurrent HUS based on strict clinical and histological features and in 4 of these patients grafts were loss from recurrent HUS, with 1 patient losing three successive grafts. Three patients had histological features consistent with HUS but lacked some of the clinical features. Seven patients had no evidence of recurrent HUS post transplantation. The incidence of recurrence of HUS post transplantation in this updated report remains high (7/17 patients). There was no difference in the allografts used (living-related donor grafts were more common in all groups) or in the immunosuppression in the different groups of patients; only 1 patient with recurrent HUS received cyclosporine. The published cases of transplantation in patients with HUS show a variable recurrence rate of 0-25% in different centers with a poor graft outcome in patients with recurrence; a higher incidence of early chronic vascular rejection with decreased graft survival is also reported in patients without recurrence. Patients with HUS post renal transplant are at a variable risk of recurrence of HUS or decreased graft survival, and the factors responsible for this outcome are not known.

Acute lung rejection after heart-lung transplantation: correlation of findings on chest radiographs with lung biopsy results

This retrospective study was performed to determine if the chest radiograph could serve as a predictor for acute lung rejection in heart-lung transplantation patients. The findings on chest radiographs were correlated with the results of transbronchial biopsies in 16 heart-lung transplantation patients. The chest radiographs immediately preceding 83 biopsies were evaluated for a variety of findings. The histopathologic results of the lung biopsies were divided into five categories: (1) acute lung rejection (n = 25); (2) suggestive, but not diagnostic, of acute lung rejection (n = 8); (3) nonspecific (n = 26); (4) infection (n = 17); and (5) normal lung (n = 9). Biopsies from two patients showed both acute lung rejection and cytomegalovirus infection and were included in both categories. These histopathologic results were then correlated with the radiologic observations. We found that the combination of septal lines and new or increasing pleural effusions, without concomitant increase in cardiac size or vascular pedicle width, or evidence of vascular redistribution, indicated acute lung rejection with a sensitivity of 68% (17/25), specificity of 90% (52/58), and overall accuracy of 83% (69/83). We conclude that the chest radiograph is a useful indicator of acute lung rejection.

Manifestations of renal allograft rejection in small children receiving adult kidneys

We were concerned that clinical manifestations of rejection (R) might be subtle in small children transplanted with adult kidneys. We retrospectively analyzed the first rejection episode (biopsy proven) in 22 children (R group) under age 4 years [mean age, 23.7 +/- 2.2 months (+/- SEM); mean weight, 9.4 +/- 0.4 kg] receiving an adult-related donor kidney. We matched these patients for age, date of transplant, donor source and immunosuppression with 36 children without R (control or C group). We compared both groups at similar intervals from transplantation, based on the time of R (5.38 +/- 1.2 months) in the R group and analyzed the immediate 8-week period prior to R and the corresponding interval in the C group. Hypertension occurred in 82% (18/22) of the R versus 8% (3/36) of the C group (P less than 0.01). Fever longer than 7 days occurred in 45% (10/22) of the R versus 0% (0/36) of the C group (P less than 0.01). Increased creatinine occurred in only 45% (10/22) of the R versus 3% (1/30) of the C group (P less than 0.01). Cyclosporine did not influence these manifestations of R. The clinical manifestations did not predict the R grades on biopsy, which were moderate to severe in 13 and mild in 9 of the R patients. Graft survival was higher at 3 years in the C (95%) than in the R patients (65%), (P less than 0.004). Thus, clinical manifestations of acute R can be subtle in small children with adult renal allografts. Renal biopsy should not be delayed until the creatinine is elevated in these patients.

Doppler evaluation of renal transplants in children: a prospective analysis with histopathologic correlation

Duplex Doppler sonography recently has been used to evaluate renal transplants. Some authors have stated that high resistive indexes (RIs) occur in the presence of acute renal transplant rejection. RIs less than 0.7 are considered as probably excluding acute transplant rejection. We performed a prospective study of duplex sonographic examinations of pediatric patients (mean age, 8 years; 13 boys, two girls) with renal allografts and clinically suspected transplant disease. The results of 22 duplex studies were correlated with histopathologic data obtained between July 1987 and June 1988. RIs of the arcuate arteries in patients with acute rejection (n = 14) averaged 0.62 (range, 0.50-0.80). The RI in patients with chronic rejection (n = 1) was 0.59. RIs in patients with acute tubular necrosis (n = 3) averaged 0.66 (range, 0.59-0.72). RIs in patients with cyclosporine A toxicity (n = 4) averaged 0.66 (range, 0.58-0.79). Tubulointerstitial rejection was predominant, with only two patients showing minimal acute vascular rejection. Thirteen of 14 pediatric patients with histologically proved renal transplant rejection had a resistive index of less than 0.70. This study refutes the concept that resistive indexes of less than 0.7 exclude acute rejection.

Evaluation of heart-lung transplant recipients with prospective, serial transbronchial biopsies and pulmonary function studies

The insidious development of obliterative bronchiolitis after heart-lung transplantation is thought to be due to rejection and possibly infection (cytomegalovirus). To evaluate further, we prospectively managed the last 16 consecutive heart-lung transplant recipients with serial transbronchial biopsies with lavage and pulmonary function studies as part of a surveillance protocol or as dictated by clinical presentation. A total of 123 transbronchial biopsies with lavage were performed, 77 for clinical indications (group I) and 46 for routine surveillance (group II). Results of 64 (83.1%) group I biopsies were positive for rejection or infection. Thirty-one of these biopsy specimens showed signs of rejection (29 in group I and two in group II), characterized by a perivascular mononuclear infiltrate, lymphocytic bronchiolitis, and occasionally alveolar septal mononuclear infiltrate. Forty-six serial pulmonary function tests were performed. The forced expiratory volume in 1 second (percent predicted), forced expiratory flow rate between 25% and 75% of the forced vital capacity (percent predicted), and arterial oxygen tension (millimeters of mercury) were significantly reduced from baseline values during rejection episodes: forced expiratory volume in 1 second, 75.7% +/- 20.1% versus 52.7% +/- 18.3% (p less than or equal to 0.05); forced expiratory flow rate between 25% and 75% of the forced vital capacity, 97.6% +/- 30.5% versus 49.8% +/- 22.3% (p less than or equal to 0.05); and arterial oxygen tension, 92.1 +/- 8.8 mm Hg versus 71.4 +/- 18.8 mm Hg (p less than or equal to 0.05). The fall in pulmonary function was reversible with pulse methylprednisolone. Asynchronous heart and lung rejection was documented. Of the 29 episodes of pulmonary rejection, 18 (62%) occurred asynchronously. Ten of the 16 (62%) heart-lung recipients had at least one episode of cardiac rejection. Thirteen of 16 (81%) had at least one episode of lung rejection. Serial transbronchial biopsies with lavage, as dictated by pulmonary function tests and clinical status, have guided early and more specific therapy directed against rejection and infection. With early detection, small airway dysfunction has been reversible.

Outcome of the acute glomerular injury in proliferative lupus nephritis

Treatment with total lymphoid irradiation (TLI) and corticosteroids markedly reduced activity of systemic lupus erythematosis in 10 patients with diffuse proliferative lupus nephritis (DPLN) complicated by a nephrotic syndrome. Physiologic and morphometric techniques were used serially before, and 12 and 36 mo post-TLI to characterize the course of glomerular injury. Judged by a progressive reduction in the density of glomerular cells and immune deposits, glomerular inflammation subsided. A sustained reduction in the fractional clearance of albumin, IgG and uncharged dextrans of radius greater than 50 A, pointed to a parallel improvement in glomerular barrier size-selectivity. Corresponding changes in GFR were modest, however. A trend towards higher GFR at 12 mo was associated with a marked increase in the fraction of glomerular tuft area occupied by patent capillary loops as inflammatory changes receded. A late trend toward declining GFR beyond 12 mo was associated with progressive glomerulosclerosis, which affected 57% of all glomeruli globally by 36 mo post-TLI. Judged by a parallel increase in volume by 59%, remaining, patent glomeruli had undergone a process of adaptive enlargement. We propose that an increasing fraction of glomeruli continues to undergo progressive sclerosis after DPLN has become quiescent, and that the prevailing GFR depends on the extent to which hypertrophied remnant glomeruli can compensate for the ensuing loss of filtration surface area.