Blood Group A antigen expression on cardiac endothelium is highly individualized: possible implications for transplantation.

BACKGROUND: Outcomes in cases of adult accidental ABO incompatible cardiac transplantation are highly variable, with some patients suffering nearly immediate catastrophic antibody-mediated rejection while others (~37%-45%) survive. We hypothesize that these disparate outcomes could be influenced by variations in blood group antigen expression on allograft endothelium. METHODOLOGY: Immunohistochemical stains for blood Group A antigen were performed on cardiac tissue from 18 blood Type A cadavers. Staining was evaluated by two distinct modalities: semiquantitative light microscopy, which measured the intensity of antigen expression on endothelium, and quantitative digital analysis, which determined the percentage of the total tissue section area staining positive for blood Group A antigen. These data were used to compute a Comprehensive Expression Index (CEI) of blood Group A antigen expression for each specimen. RESULTS: Semiquantitative light microscopic examination determined that endothelium was stained with low intensity in four (22%) myocardial samples, intermediate intensity in five (28%) samples, and high intensity in nine (50%) samples. Quantitative digital analysis revealed a range in the percentage of total cross sectional area composed of blood Group A-positive signal (median, 2.69%; interquartile range, 1.68%-2.94%). Increased percentage of total cross sectional area composed of blood Group A-positive signal was positively associated with patient age (P=.0037). The CEI showed a broad range, with a median of 5.27 and an interquartile range of 2.92-8.22. CONCLUSIONS: There are little data available regarding interindividual differences in blood Group A antigen expression in cardiac endothelium. Here, we report interindividual variation in endothelial expression of blood Group A antigen in 18 specimens. These variations may help to explain disparate outcomes in cases of accidental ABO incompatible cardiac transplantation in adults.

MALDI-MS derived prognostic protein markers for resected non-small cell lung cancer.

Protein signals obtained directly from frozen lung tissue sections using MALDI-MS were used to predict nodal involvement and survival in resected non-small cell lung cancer (NSCLC). We have identified a list of these protein signals and further evaluated their prognostic values for NSCLC using immunohistochemistry (IHC). Kaplan-Meier analysis was used to assess the mortality risk associated with the prognostic protein IHC-staining intensities. The combined IHC scores of calmodulin, thymosin ß4, and thymosin ß10 were found to be correlated with NSCLC patient survival (p = 0.004). Furthermore, low cofilin-1 IHC-staining intensity was found to be correlated with a better outcome for patients with negative lymph node status (p = 0.006) while high cofilin-1 IHC-staining intensity was found to be correlated with a better outcome for patients with positive node status (p = 0.034). In conclusion, the prognostic protein signals selected using MALDI-MS can be identified and tested by IHC in formalin-fixed tissue samples. MALDI-MS-derived protein signals can be potentially translated to a conventional clinical setting to aid in the prognosis of patients with NSCLC at the molecular level.

The histopathology of fatal untreated human respiratory syncytial virus infection.

The pathology of respiratory syncytial virus (RSV) infection was evaluated 1 day after an outpatient diagnosis of RSV in a child who died in a motor vehicle accident. We then identified 11 children with bronchiolitis from the Vanderbilt University autopsy log between 1925 and 1959 who met criteria for possible RSV infection in the preintensivist era. Their tissue was re-embedded and evaluated by routine hematoxylin and eosin and PAS staining and immunostaining with RSV-specific antibodies. Tissue from three cases was immunostain-positive for RSV antigen and was examined in detail. Small bronchiole epithelium was circumferentially infected, but basal cells were spared. Both type 1 and 2 alveolar pneumocytes were also infected. Although, not possible for archival cases, tissue from the index case was evaluated by immunostaining with antibodies to define the cellular components of the inflammatory response. Inflammatory infiltrates were centered on bronchial and pulmonary arterioles and consisted of primarily CD69+ monocytes, CD3+ double-negative T cells, CD8+ T cells, and neutrophils. The neutrophil distribution was predominantly between arterioles and airways, while the mononuclear cell distribution was in both airways and lung parenchyma. Most inflammatory cells were concentrated submuscular to the airway, but many cells traversed the smooth muscle into the airway epithelium and lumen. Airway obstruction was a prominent feature in all cases attributed to epithelial and inflammatory cell debris mixed with fibrin, mucus, and edema, and compounded by compression from hyperplastic lymphoid follicles. These findings inform our understanding of RSV pathogenesis and may facilitate the development of new approaches for prevention and treatment.

Oxidized low-density lipoprotein is present in astrocytes surrounding cerebral infarcts and stimulates astrocyte interleukin-6 secretion.

Ischemic injury to brain is associated with both disruption of the blood-brain barrier and increased oxidative stress. Given the neurotoxicity associated with exposure to oxidized low-density lipoprotein (oxLDL) in vitro, we tested the hypothesis that oxLDL may be present in parenchymal cells of cerebrum after infarction and that oxLDL may influence the pathophysiology of cerebral infarction. Our results showed that the subacute phase of cerebral infarction in patients was characterized by the appearance of oxLDL epitopes in astrocytes, but not neurons or microglia, in the perinecrotic zone. We further demonstrated that minimally oxLDL was most effectively internalized by primary cultures of rat astrocytes, and that exposure to minimal oxLDL stimulated astrocyte interleukin-6 secretion but did not alter nitric oxide production. These results demonstrate for the first time that oxLDL is present in brain parenchyma of patients with ischemic infarction and suggest a potential mechanism by which oxLDL may activate innate immunity and thereby indirectly influence neuronal survival.

Immunohistochemical localization of carboxypeptidases D, E, and Z in pituitary adenomas and normal human pituitary.

Carboxypeptidases may play important role(s) in prohormone processing in normal and neoplastic adenohypophyseal cells of the pituitary. We have recently demonstrated carboxypeptidase E (CPE) and carboxypeptidase Z (CPZ) in the majority of adenohypophyseal cells with carboxypeptidase D (CPD) immunoreactivity largely confined to adrenocorticotrophs. This study evaluated the expression patterns of CPE, CPD, and CPZ immunoreactivity in 48 pituitary adenomas. Our immunohistochemistry demonstrated extensive intracytoplasmic immunoreactivity for CPE, CPD, and CPZ in adrenocorticotrophic hormone (ACTH)-producing adrenocorticotroph cells, prolactin-producing lactotroph cells, and growth hormone (GH)-producing somatotroph cell adenomas, all of which require carboxypeptide processing of prohormones to produce active endocrine hormones. In contrast to the restricted expression in the normal adenohypophysis, CPD appeared to be widespread in the majority of adenomas, suggesting that CPD levels are increased in adenomas. In luteinizing hormone/follicle-stimulating hormone (LH/FSH)-producing gonadotroph adenomas, which do not require carboxypeptidases to produce gonadotropins, only CPZ immunostaining was demonstrated. In null-cell adenomas, CPE immunoreactivity was detected in the majority of tumors, but CPD and CPZ were identified only in a minority of cases. CPE in these cells may process other peptides critical for pituitary cell function, such as chromogranin A or B. These findings suggest that CPs participate in the functioning of pituitary adenomas.