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Solid organ transplantation is currently the treatment of choice for renal, heart, and pancreas insufficiency and selected bowel diseases. Thanks to advances in medical technology, the lifespan of transplanted organs is currently about 10 years. To prevent graft rejection, patients need to take immunosuppressive drugs, usually for the rest of their Lives. Pathologists play a crucial role in organ transplantation. They are responsible for recognizing allograft rejection, both acute and chronic, differentiating rejection from drug toxicity, and identifying recurrent disease. In addition, pathologists identify new diseases in the graft, opportunistic infections in the transplanted organ or other organs, and the development of malignant tumors, which are more common in immunocompromised patients. Accordingly, transplant pathologists require a wide range of knowledge in many complex laboratory techniques, such as immunofluorescence, electron microscopy, immunohistochemical analysis, and molecular pathology. These tests are performed in dedicated Laboratories in departments of pathology. TranspLant pathology is an inseparable part of the field of transplantation medicine and greatly assists clinicians in the diagnosis of disease processes in transplanted organs and in the selection of appropriate treatment.

erbB receptors contribute to tumor formation and progression. Variable expression of erbB1, erbB2, and erbB3 has been reported in nevi and melanomas; erbB4 has hardly been investigated. We examined the expression of all 4 erbB receptors in common and dysplastic nevi and melanomas. Formalin-fixed, paraffin-embedded tissues of 100 melanomas, 27 common nevi, and 23 dysplastic nevi were immunostained with antibodies against the 4 erbB receptors. erbB3 and erbB4 showed stronger positivity in nevi than in melanomas, and in common than in dysplastic nevi. Staining pattern was more orderly in nevi than in melanomas. Common nevi showed more prominent membranous staining for erbB3 than dysplastic nevi followed by melanomas. In melanomas, greater thickness was associated with more widespread erbB2 and erbB3 staining in the vertical than in the radial growth phase, and in the dermal than in the epidermal component. Higher mitotic counts were associated with more widespread and intense erbB2 expression in the vertical growth phase than in the radial growth phase and in the dermal than in the epidermal component. Melanomas with more widespread erbB2 staining had heavier lymphocytic infiltrates. erbB1 expression was negligible in all groups. erbB2, erbB3, and erbB4 are expressed in all subtypes of melanocytic lesions, but with quantitative and qualitative differences. Receptor expression seems to decrease and to become less mature and orderly with tumor progression. The complex patterns of erbB receptor expression in melanocytic lesions warrant further investigation.

Problem: While relying on previous publications, our aim was to examine the morphologic changes, induced in early rat embryos by intra-uterine exposure to the low-molecular weight fraction of boiled human serum containing antiphospholipid antibodies (APLA) that had been obtained from women with antiphospholipid syndrome (APS)., Method of Study: Human APLA-positive sera were pooled, boiled, centrifuged and separated by ultrafiltration. The molecular weight fraction lower than 30 kDa was used for the experiments. One hundred and fifty microlitres was injected into one uterine horn of 12 pregnant rats, 5 or 6 days after fertilization, while similarly prepared normal human serum or saline were injected into the contralateral horn. The rats were subsequently sacrificed. Serial sections, obtained from all uterine horns, were stained histologically and immunohistochemically. Normal embryos developed in the control uterine horns, while embryos in the experimental horns were destroyed rapidly., Results: Signs of apoptosis appeared 2 hr following the injection, and 4 hr later all the embryonic cells were apoptotically destroyed. There was only partial damage to cytotrophoblasts and intermediate trophoblasts., Conclusion: These findings support the existence of a novel factor in the APLA-positive serum, causing a detrimental effect to the conceptus, without any relation to the antiphospholipid antibodies.

Problem: Morphologic changes in the placental barrier in spontaneous early abortions under the maternal-embryonic immune conflict, and the role of maternal immunoglobulins (Igs) in these changes., Materials and Methods: We examined chorionic villi and other tissues obtained from 54 aborts between weeks 3.5 and 8 of pregnancy. Material was divided into two groups. Group 1 (control) contained 15 medically recommended and spontaneous early aborts with no signs of inflammations or pathologic immune processes. Group 2 contained 39 spontaneous early aborts with acute chorionic villitis. Immunohistochemical and morphometric methods were used to study the Igs, different types of immunocompetent cells, and apoptosis-related components of the placental barrier., Results: Acute villitis was found to be characterized by the destruction of all components of the chorionic villi, thrombovasculitis with apoptosis of the endothelium of capillaries and erythroblasts, mucous swelling of the basal membrane, and coagulation of the blood proteins. Due to destruction of the capillaries, the number of avasculate villi increased, and the average number of capillaries per villus decreased. The extremely high number of phagolysosomes with IgG and IgA in the villous monocytes in the group 2 indicates an increase in the phagocytic activity of monocytes against maternal Igs and may reflect the presence of mother-embryo immune conflict. Apoptosis of monocytes and a high number of promonocytes were seen accompanied by a high concentration of p53 protein. A large disturbance in the trophoblast occurred with disappearance of bcl-2 and the appearance of Fas ligand., Conclusion: Massive destruction of maternal Igs in embryonic monocytes and acute villitis in the placental barrier are manifested during the mother-embryo immune conflict, and this may be one of the reasons of spontaneous early abortions.

Objective: To evaluate the potential protective affects of Epo on left ventricular (LV) function and remodeling after acute myocardial infarction (MI)., Methods: Epo was injected into the peritoneum of male Wistar rats (250 g) during 6 weeks post induction of MI. Rats were divided into five groups: MI treated with single high dose (MT1, 5,000 U/kg, n=10), single high dose (5,000 U/kg) and repeated high doses (MTHi, 1,000 U/kg twice a week; n=8), or single high dose (5,000 U/kg) and repeated low doses (MTLo, 750 U/kg once a week, n=10), MI non-treated (MNT, n=10), sham (S, n=5). Echocardiography was performed 3.6+/-1.5 days and 43.7+/-2.3 days post MI. Collagen deposition and infarct size were measured on histological sections using computerized image analysis. Apoptosis was assessed by ApopTag staining., Results: Baseline fractional shortening (FS) was similar between groups. Six weeks after MI the FS of MTLo (26.9%) was significantly higher compared to MNT (17.8%), MT1 (19.5%) and MTH (22.3%) (p=0.01). However, remodeling indices (end diastolic and end systolic areas, LV circumference) did not improve in the Epo groups, and even worsened in the MTHi group. There was significantly less collagen staining in non-infarct areas in MT1 and MTHi groups compared to MNT and MTLo (0.38+/-0.3%, 0.49+/-0.34%, vs 0.89+/-0.41%, 0.95+/-0.33%, respectively, p<0.001). The number of ApopTag positive nucleus was significantly higher in the MNT group compared to the MT1, MTHi, MTLo groups (14.4+/-8, 7.6+/-4, 5.8+/-7, 4.8+/-5, respectively, p=0.01 for trend)., Conclusion: Repeated low doses of Epo after MI improved LV function, but the role of Epo on remodeling is not clear. It did not reduce left ventricular indices, but reduces fibrosis and apoptosis. High Epo doses reduced LV function and aggravated remodeling.

Background: Mycosis fungoides (MF) is an epidermotropic cutaneous T-cell lymphoma in which the tumor cells express a mature T-helper memory phenotype, ie, CD3(+), CD4(+), CD8(-), CD45RO(+), with a T-cell receptor (TCR) of the alpha/beta heterodimer. A minority of patients have an unusual immunohistochemical profile consisting of a CD4(-), CD8(+) mature T-cell phenotype. An aberrant CD4/CD8 double-negative (DN) immunophenotype in patients with early MF has rarely been reported., Objectives: We sought to evaluate the frequency of CD4/CD8 DN immunophenotype in patients with early MF, and to study their clinical, histopathologic, and immunohistochemical features, and the course of their disease., Methods: Our departmental archives were searched for patients with early-stage MF and CD4/CD8 DN immunophenotpye., Results: Of the 140 patients with early MF immunophenotyped in our laboratory, 18 (12%) showed CD4 and CD8 expression in less than 10% of their intraepidermal T cells on fresh-frozen and paraffin-embedded samples. The group included 13 male and 5 female patients; 14 adults and 4 children; and 15 Jews and 3 Arabs. In all, 8 had classic MF and 10 had unusual clinical variants (5 hypopigmented, 3 localized, 1 ichthyosiform, 1 purpuric). All received skin-targeted therapies and all had an indolent course (mean follow-up 3.5 years). Histopathology revealed early MF. Results of immunohistochemical analysis of the intraepidermal lymphocytes were as follows: CD3(+), CD4(-), CD8(-) in all patients; CD7(-) in all of 17; CD45RO(+) in 15 of 16; T-cell-restricted intracellular antigen-1(+) in 11 of 15; CD30(+) in 2 of 16; and CD56(+) in 2 of 16. A betaF1(+)/delta(-) phenotype, indicating a TCR of the alpha/beta heterodimer, was found in 8 of 16; betaF1(-)/delta(+) phenotype, indicating a TCR of the gamma/delta heterodimer, in 1 of 16; betaF1(-)/ delta(-) in 5 of 16; and no determinable phenotype in 2 of 16. The TCR gamma gene was clonally rearranged in 10 of 16 patients., Limitation: This was a single-center case series., Conclusions: There is a subgroup of patients with early MF that exhibit a CD4/CD8 DN immunophenotype. In our region, this aberrant immunophenotype is not as rare as reflected in the literature, is overrepresented in the unusual clinical variants of MF, and does not seem to have prognostic significance. Like CD4(+) MF, the tumor cells represent memory T cells and in many cases express alpha/beta TCR, but unlike CD4(+) MF, they have a mostly cytotoxic phenotype. We suggest that CD4/CD8 DN MF should be recognized as another immunohistochemical variant of this lymphoma.

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine tumor of the skin that is associated with a high incidence of recurrence and metastasis. The therapeutic arsenal for this malignancy is limited and once it spreads, there is no effective treatment. c-kit expression has been demonstrated previously in primary MCCs thus raising the possibility of treating MCCs with imatinib mesylate, the tyrosine kinase inhibitor that has shown promise in the management of c-kit expressing tumors. In this study we examine 25 additional primary MCCs and also 6 of their lymph node metastases. Formalin-fixed, paraffin-embedded tissues were stained immunohistochemically with an antibody directed against the KIT receptor. Percentage and intensity of staining were analyzed semiquantitatively using a three-tiered system. Twenty-one of the 25 (84%) primary tumors stained positively for KIT, of which 14 (67%) showed widespread positivity. Five of the 6 lymph nodes (83%) were similarly positive. High mitotic rate and vascular invasion in the primary tumors tended to be associated with prominent staining in the lymph node metastases. No association was found between c-kit expression and outcome. We confirm that the majority of primary MCCs express c-kit and further find that metastases are positive for the KIT receptor as well. Thus, c-kit expression may be an early event in the transformation of MCC, but not a marker for tumor progression.

Squamous cell carcinomas of the head and neck (SCCHN) are excellent candidates for local immunotherapy owing to their accessibility and their infiltration by mononuclear cells that are susceptible to immunomodulation. A response rate of 25-60% has been reported for treatment with natural IL-2 or a mixture of natural lymphokines. In the present study, biopsies and posttreatment excision specimens from nine patients with operable SCCHN treated systemically with a variety of immunomodulators and locally with natural lymphokines (multikine, CelSci) were analyzed in an attempt to correlate clinical response to histopathological and immunohistochemical changes. Formalin-fixed, paraffin-embedded tissues were stained with antibodies against lymphocytes (CD45, CD3, CD4, CD8, CD20), macrophages (CD68) including dendritic cells (S-100), markers for lymphocyte activation (CD30, HLA-DR), natural killer cells (CD56 and CD57), beta-2-microglobulin and keratin. One patient showed a complete response to treatment and two a partial response. Tumor size was significantly smaller after therapy. Clinical and pathological regression were more prominent in the smaller tumors. Numerous macrophages, both mononucleated and multinucleated, were present along the tumor-stroma interface in the posttreatment specimens of seven patients, most prominently in the three patients with tumor regression. The increase in the number of CD68+ and S-100+ macrophages after treatment was statistically significant. Lymphocytic infiltrates, which showed some increase following treatment, were composed of a mixture of T and B lymphocytes, the former mostly in contact with the tumor and the latter placed more peripherally. CD8+ lymphocytes extended into the tumors, whereas CD4+ lymphocytes showed minimal extension. Intensity of beta-2-microglobulin staining in tumors was significantly higher following therapy and associated with a better outcome. The marked increase in macrophages following treatment may indicate that the macrophage plays a major role in tumor recognition, destruction and clearance. An increase in the number of macrophages in a posttreatment specimen may indicate immunoresponsiveness.

Atrial natriuretic peptide (ANP), the principal member of the natriuretic factor family of peptides, primarily a product of the atria in the adult heart, is also expressed in the fetal ventricles. A minority of ventricular impulse-conducting cells and myocytes exposed to extreme tension retain the capacity to produce ANP in the adult. The number and distribution of ANP-expressing cells increases dramatically when the ventricle is pressure loaded and hypertrophied, as in the case of chronic hypertension. Coregulation of hypertrophy and ANP expression has established this peptide as a marker of myocardial hypertrophy and of the activation of the fetal gene program, typical of this condition. However, a coordinated reduction of hypertension and ANP expression while hypertrophy persists indicates that the hemodynamic state overrules hypertrophy in controlling ANP expression in hypertensive rat hearts. Under these circumstances, reduced activity of the cardiac-restricted transcription factor GATA-4 (a regulator of both hypertrophy and ANP expression) correlated with ANP downregulation but not with hypertrophy, which remained unchanged. Therefore, maintenance of cardiac hypertrophy in essential hypertension may not be dependent solely on GATA activity: it seems that additional factors may be involved. It is suggested that cell size and ANP production are autonomous features of the myocyte in the hypertensive heart and, although governed by similar mechanisms, the two features may be manifested independently.

Background: Warm ischemia/reperfusion injury during liver transplantation is the most important cause of primary nonfunction of liver allografts. Tumor-necrosis factor (TNF)-alpha apparently mediates tissue damage by inducing apoptosis and/or necrosis in liver transplants. The aim of the study was to determine, using an isolated rat liver model, if pretreatment with anti-TNF-alpha monoclonal antibodies can attenuate ischemia/reperfusion liver injury. Specifically, its effect on liver cell apoptosis through the modulation of caspase activity was examined in a blood-free environment., Methods: Isolated rat livers were perfused with Krebs-Henseleit solution and randomly divided into three groups: (1) continuous perfusion for 165 min (control); (2) perfusion for 90 min, break for 60 min (ischemia), and reperfusion for 15 min; (3) as with group 2, but with administration of monoclonal mouse anti-rat TNF-alpha monoclonal antibodies before induction of ischemia. Caspase-3- and -9-like activity was measured by fluorometric assay, and apoptotic cells were identified by morphological criteria and application of the terminal deoxnucleotidyl transferase-mediated dUTP nick-end-labeling (Tunel) assay., Results: Portal pressure increased significantly in group 2 (14.8+/-2.3 mm Hg) compared to group 3, which showed no change (P<0.05). Significant amounts of TNF-alpha were detected in the effluent in group 2 at 1 min of reperfusion (147+/-8.9 pg/ml) compared to group 3 (30+/-6.7 pg/ml, P<0.05). Statistically significant reductions in liver enzyme levels were also noted in the animals pretreated with TNF-alpha antibodies (P<0.02). Caspase-3 and -9 activity was significantly decreased (270 and 160%, respectively) in group 3 compared to group 2 (P<0.005 and <0.05, respectively). A significant reduction in postischemic hepatic injury was noted on Tunel assay: many apoptotic hepatocyte cells were detected in group 2 but not in livers pretreated with monoclonal mouse anti-TNF-alpha antibodies (group 3)., Conclusions: Neutralization with specific monoclonal antibodies against TNF before ischemia induction can attenuate postischemic hepatic injury. Apoptotic injury seems to be ameliorated through modulation of caspase-3- and -9-like activity.

p73 is the first identified homolog of p53, but its function has not been established. Our study investigated the expression of p73 in liver tissue of patients with hepatitis C virus (HCV)-associated hepatocellular carcinoma (HCC). RT-PCR was performed on RNA extracted from tumorous and nontumorous liver tissue of HCV-associated HCC, and control tissue and the cDNA were sequenced. Anti-p73 polyclonal antibodies were used for protein analysis and immunohistochemistry, and patients' sera were analyzed for anti-p73 antibodies by radioimmunoassay. Analysis of the p53 gene was performed by SSCP and RFLP-PCR. The p73 mRNA and protein were highly expressed and accumulated in HCC tissues. Immunohistochemical studies revealed significant immunoreactivity in the nuclei of HCC cells. No mutations were detected in the p73 gene or in p53, and no loss of heterozygosity of the p53 gene was found. Anti-p73 antibodies were detected in sera of HCC patients, but were not significantly different from that occurring in non-HCV or non-HCC patients. In conclusion, p73 protein is overexpressed and accumulates in the nuclei of HCV-associated HCCs and may play a role in HCC development.

Gonadotropin-releasing hormone (GnRH) analogues are used for the treatment of breast, prostate, and ovarian cancer. These analogues exert their antitumor effects indirectly by inhibiting the pituitary-gonadal axis, as well as by direct inhibition of proliferation of human breast cancer cells. However, the molecular mechanisms mediating these direct antiproliferative effects are not fully understood. We found that normal and malignant human breast tissue express two forms of the neuropeptide GnRH. Quantitative reverse transcription-PCR shows that mRNA encoding the GnRH-I and GnRH-II peptides are overexpressed in cancerous versus normal tissues obtained from the same patients. To elucidate the function of these peptides in breast cancer cells, we used the atlas human cDNA expression arrays technology and studied the differentially regulated genes after GnRH treatment of MCF-7 cells. We found that a wide range of GnRH-I or GnRH-II concentrations (0.1-10 nM) inhibit the expression of mRNA encoding the 60S acidic ribosomal phosphoproteins, P1 and P2. These results were confirmed by quantitative reverse transcription-PCR, as well as Western blot analysis and immunofluorescence staining. The P1 and P2 proteins interact with elongation factors EF1 and EF2, and the level of their phosphorylation is one of the regulatory mechanisms for the overall rate of protein elongation. Thus, reduced expression of P1 and P2 proteins can affect the rate of protein translation, thereby decreasing proliferation rate of cells. Our studies may therefore suggest a putative mechanism for the direct antiproliferative effect of GnRH in breast cancer cells.

In the ventricles of adult mammalian hearts, production of atrial natriuretic peptide (ANP) is negligible, restricted to the impulse-conducting cells, the papillary muscles, and a minority of subendocardial myocytes. ANP expression is reinduced in the ventricles of pressure-overloaded and failing hearts and is frequently used as a marker for myocyte hypertrophy. Using an immunohistochemical approach, we have characterized the size distribution of ANP-containing myocytes in the left ventricle of the spontaneously hypertensive rat (SHR) before and after chronic antihypertensive therapy and compared the results to age-matched normotensive Wistar rats (WR). Our findings show that in SHR the frequency of cells presenting ANP granularity is positively correlated with myocyte size (r=0.746, P<0.02). The highest proportion of ANP-positive myocytes (55-57%) was measured among cells of diameters 30-34 microm. In any corresponding cell size, the proportion of ANP-presenting myocytes was five- to tenfold higher in SHR than in the normotensive WR. We studied the effects of the antihypertensive drugs captopril, hydralazine, and nifedipine and found that, regardless of their effect on blood pressure or hypertrophy, all three eliminated ANP immunoproducts from the majority of the left ventricular myocytes and reduced the level of ANP mRNA, captopril being the most effective. The positive correlation between myocyte size and ANP expression was not maintained in the hearts of drug-treated SHR. Myocytes on the border of fibrotic areas or in regions of ANP presentation within the normal heart resisted the suppressive effect of the antihypertensive therapy, indicating that blood pressure or hypertrophy are not the sole correlates for ANP expression.

Inflammatory destruction of insulin-producing beta cells in the pancreatic islets is the hallmark of insulin-dependent diabetes mellitus, a spontaneous autoimmune disease of non-obese diabetic mice resembling human juvenile (type I) diabetes. Histochemical analysis of diabetic pancreata revealed that mononuclear cells infiltrating the islets and causing autoimmune insulitis, as well as local islet cells, express the CD44 receptor; hyaluronic acid, the principal ligand of CD44, is detected in the islet periphery and islet endothelium. Injection of anti-CD44 mAb 1 hr before cell transfer of diabetogenic splenocytes and subsequently on alternate days for 4 weeks induced considerable resistance to diabetes in recipient mice, reflected by reduced insulitis. Contact sensitivity to oxazolone was not influenced by this treatment. A similar antidiabetic effect was observed even when the anti-CD44 mAb administration was initiated at the time of disease onset: i.e., 4-7 weeks after cell transfer. Administration of the enzyme hyaluronidase also induced appreciable resistance to insulin-dependent diabetes mellitus, suggesting that the CD44-hyaluronic acid interaction is involved in the development of the disease. These findings demonstrate that CD44-positive inflammatory cells may be a potential therapeutic target in insulin-dependent diabetes.

Objective: To create monoclonal anti-endothelial cell antibodies (mAECA) from a patient with Takayasu arteritis to evaluate their ability to activate human umbilical vein endothelial cells (HUVEC), and to characterize the mechanism of EC activation., Methods: A panel of mAECA was generated from peripheral blood lymphocytes of a patient with Takayasu arteritis, using Epstein-Barr virus transformation. Activity against macrovascular EC (HUVEC) and microvascular EC (human bone marrow EC immortalized by SV40) antigens was detected by enzyme-linked immunosorbent assay. Inhibition studies were used to select the monoclonal antibodies (mAECA) which share the same EC epitope binding specificity as the total IgG-AECA from the Takayasu arteritis patient. The binding of the mAECA to human aortic EC was studied by immunohistochemistry. The secretion levels of interleukin-6 (IL-6) and von Willebrand factor (vWF) were determined, to serve as markers for EC activation. The activated EC were examined for the adherence of a monocytic cell line (U937), as well as for expression of vascular cell adhesion molecule 1, intercellular adhesion molecule 1, and E-selectin. In addition, nuclear extracts of the mAECA-treated EC were analyzed for the induction of translocation of nuclear factor kappaB (NF-kappaB), using a specific NF-kappaB oligoprobe in an electrophoretic mobility shift assay., Results: Six mAECA were selected, the mixture of which produced 100% inhibition of binding of the original IgG (from the patient with Takayasu arteritis) to HUVEC. All mAECA possessed high activity against macrovascular EC, but none had significant antimicrovascular EC activity. The mAECA, but not normal human IgG, had anti-human aortic EC activity. Four of the 6 mAECA activated EC, manifested by increased IL-6 and vWF secretion. The 4 mAECA induced EC expression of adhesion molecules and increased adhesion of U937 monocytic cells to EC. In addition, these mAECA stimulated the nuclear translocation of the NF-kappaB transcription factor., Conclusion: Our findings suggest that AECA may directly stimulate EC in Takayasu arteritis through elevation of adhesion molecule expression associated with NF-kappaB activation and adhesion of monocytes, and may therefore play a pathogenic role in the development of the vasculopathy in Takayasu arteritis.