Untargeted screening for novel autoantibodies with prognostic value in first-episode psychosis.

Immunological and inflammatory reactions have been suggested to have a role in the development of schizophrenia, a hypothesis that has recently been supported by genetic data. The aim of our study was to perform an unbiased search for autoantibodies in patients with a first psychotic episode, and to explore the association between any seroreactivity and the development of a Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) disorder characterized by chronic or relapsing psychotic symptoms. We collected plasma samples from 53 patients when they were treated for their first-episode psychosis, and 41 non-psychotic controls, after which the patients were followed for a mean duration of 7 years. Thirty patients were diagnosed with schizophrenia, delusional disorder, schizoaffective disorder, bipolar disorder or a long-term unspecified nonorganic psychosis during follow-up, whereas 23 patients achieved complete remission. At the end of follow-up, plasma samples were analyzed for IgG reactivity to 2304 fragments of human proteins using a multiplexed affinity proteomic technique. Eight patient samples showed autoreactivity to the N-terminal fragment of the PAGE (P antigen) protein family (PAGE2B/PAGE2/PAGE5), whereas no such autoreactivity was seen among the controls. PAGE autoreactivity was associated with a significantly increased risk of being diagnosed with schizophrenia during follow-up (odds ratio 6.7, relative risk 4.6). An immunohistochemistry analysis using antisera raised against the N-terminal fragment stained an unknown extracellular target in human cortical brain tissue. Our findings suggest that autoreactivity to the N-terminal portion of the PAGE protein family is associated with schizophrenia in a subset of patients with first-episode psychosis.

Surface single-molecule dynamics controlled by entropy at low temperatures.

Configuration transitions of individual molecules and atoms on surfaces are traditionally described using an Arrhenius equation with energy barrier and pre-exponential factor (attempt rate) parameters. Characteristic parameters can vary even for identical systems, and pre-exponential factors sometimes differ by orders of magnitude. Using low-temperature scanning tunnelling microscopy (STM) to measure an individual dibutyl sulfide molecule on Au(111), we show that the differences arise when the relative position of tip apex and molecule changes by a fraction of the molecule size. Altering the tip position on that scale modifies the transition's barrier and attempt rate in a highly correlated fashion, which results in a single-molecular enthalpy-entropy compensation. Conversely, appropriately positioning the STM tip allows selecting the operating point on the compensation line and modifying the transition rates. The results highlight the need to consider entropy in transition rates of single molecules, even at low temperatures.

The Human Protein Atlas as a proteomic resource for biomarker discovery.

The analysis of tissue-specific expression at both the gene and protein levels is vital for understanding human biology and disease. Antibody-based proteomics provides a strategy for the systematic generation of antibodies against all human proteins to combine with protein profiling in tissues and cells using tissue microarrays, immunohistochemistry and immunofluorescence. The Human Protein Atlas project was launched in 2003 with the aim of creating a map of protein expression patterns in normal cells, tissues and cancer. At present, 11,200 unique proteins corresponding to over 50% of all human protein-encoding genes have been analysed. All protein expression data, including underlying high-resolution images, are published on the free and publically available Human Protein Atlas portal (http://www.proteinatlas.org). This database provides an important source of information for numerous biomedical research projects, including biomarker discovery efforts. Moreover, the global analysis of how our genome is expressed at the protein level has provided basic knowledge on the ubiquitous expression of a large proportion of our proteins and revealed the paucity of cell- and tissue-type-specific proteins.

Characterization of PrEST-based antibodies towards human Cytokeratin-17.

Antibody-based proteomics efforts depend on validated antibodies to ensure correct annotation of analyzed proteins. We have previously argued that a low sequence identity to other proteins is a key feature for antigens used in antibody generation. Thus, a major challenge for whole-proteome studies is how to address families of highly sequence related proteins within the context of generating specific antibodies. In this study, two non-overlapping parts of human Cytokeratin-17, a protein belonging to the intermediate filament family of highly sequence-related proteins, were selected as a model system to study the specificity and cross reactivity of antibodies generated towards such a target. These recombinantly produced Protein Epitope Signature Tags (PrESTs) were immunized in five rabbits each and the batch-to-batch variations in the obtained immune responses were studied by mapping of linear epitopes using synthetic overlapping peptides. The obtained results showed a similar but not identical immune response in the respective antibody groups with a limited number of epitopes being identified. Immunohistochemical analysis of the affinity purified monospecific antibodies on tissue micro arrays resulted in a general recognition of human cytokeratins for all analyzed binders whereas antibodies identified as binding to the most unique parts of the PrESTs showed the most Cytokeratin-17 like staining. The data presented here support the strategy to use sequence identity scores as the main criteria for antigen selection but also indicate the possibility to instead produce a single antibody recognizing a defined group of proteins when the intended targets overall sequence identity score is too high. This type of group-specific antibodies would be an important tool for antibody-based projects aiming for a complete coverage of the human proteome.

The dissection of CD8 T cells during liver-stage infection.

Multiple injections of gamma-radiation-attenuated Plasmodium sporozoites (gamma-spz) can induce long-lived, sterile immunity against pre-erythrocytic stages of malaria. Malaria antigen (Ag)-specific CD8 T cells that produce IFN-gamma are key effector cells in this model of protection. Although there have been numerous reports dealing with gamma-spz-induced CD8 T cells in the spleen, CD8 T cells most likely confer protection by targeting infected hepatocytes. Consequently, in this chapter we discuss observations and hypotheses concerning CD8 T cell responses that occur in the liver after an encounter with the Plasmodium parasite. Protracted protection against pre-erythrocytic stages requires memory CD8 T cells and we discuss evidence that gamma-spz-induced immunity is indeed accompanied by the presence of intrahepatic CD44hi CD45RBlo CD62lo CD122lo effector memory (EM) CD8 T cells and CD44hi CD45RBhi CD621hi CD122hi central memory (CM) CD8 T cells. In addition, the EM CD8 T cells rapidly release IFN-gamma in response to spz challenge. The possible role of Kupffer cells in the processing of spz Ags and the production of cytokines is also considered. Finally, we discuss evidence that is consistent with a model whereby intrahepatic CM CD8 T cells are maintained by IL-15 mediated-homeostatic proliferation while the EM CD8 T cells are conscripted from the CM pool in response to a persisting depot of liver-stage Ag.

Wernicke's encephalopathy in two patients with acquired immunodeficiency syndrome.

Two non-alcoholic homosexual patients with acquired immunodeficiency syndrome (AIDS) are reported who developed acute Wernicke's encephalopathy in the terminal stage of their illness. The first patient presented with vascular congestion, minute haemorrhages, proliferation of microglia and of the vessel walls at the predilection sites of the Wernicke-Korsakoff process. In the second patient only the mamillary bodies were involved. Besides Wernicke's encephalopathy, a primary cerebral immunoblastoma and cerebral toxoplasmosis were found in the first patient, whereas the second showed severe encephalitis with numerous microglial and multinucleated giant cells reacting positively with anti-HIV antibody. Just as in the development of Wernicke's encephalopathy in malignant diseases, the catabolic trend of the metabolism of the immunodeficient patients with consecutive thiamine deficiency must be considered the principal pathogenetic mechanism.

Tissue expression of the cancer-associated antigens CA 19-9 and CA-50 in chronic pancreatitis and pancreatic carcinoma.

The expression of the gastrointestinal cancer-associated antigens CA 19-9 and CA-50 was studied in 43 ductal pancreatic carcinomas, 1 mucinous cystadenoma, 1 signet-ring-cell carcinoma, 42 pancreata with chronic pancreatitis, and 10 normal fetal and adult pancreata. The anti-CA-50 antibody gave a more intense and more uniformly distributed staining of the ductal epithelial cells than the anti-CA 19-9 antibody. Both antigens, however, exhibited the same staining pattern of ductal epithelial cells in normal pancreas and chronic pancreatitis. Well differentiated carcinomas showed a predominantly membrane-bound antigen expression, whereas moderately and poorly differentiated carcinomas gave a more diffuse cytoplasmic staining. Epithelial dysplasia could not be differentiated by the staining pattern from normal, hyperplastic, metaplastic, or neoplastic cells. The immunohistochemical reaction with these anticarbohydrate antibodies, therefore, does not allow a qualitative discrimination between chronic pancreatitis and pancreatic carcinoma. CA 19-9, which expression depends on the Lewis gene, was negative in two patients with Le(a-b-) phenotype. Although anti-CA-50 antibody was reactive with the cancer cells of these 2 patients, the staining was weak and heterogenous.

Comparative study on the expression of the blood group antigens Le a, Le b, Le x, Le y and the carbohydrate antigens CA 19-9 and CA-50 in chronic pancreatitis and pancreatic carcinoma.

The expression of the blood group antigens Le a, Le b, Le x, Le y and the carbohydrate antigens CA 19-9 and CA-50 was studied in 20 ductal pancreatic carcinomas, 24 pancreases with chronic pancreatitis and 10 normal fetal and adult pancreases. CA 19-9, CA-50 and Le a showed the strongest staining intensity, the highest percentage of labelled cells, and a membrane-bound expression pattern in epithelial cells of normal pancreas, chronic pancreatitis and well differentiated (G1) carcinoma; in moderately and poorly differentiated carcinomas (G2/3) it was predominantly cytoplasmic. The staining pattern of Le b and Le x was less clearly membrane-bound but varied with cytoplasmic and Golgi-located distributions in all pancreatic specimens. Le y revealed a consistent granular antigen expression in the Golgi-region of ductal epithelial, acinar and carcinoma cells. None of the antibodies allowed a morphological differentiation by their expression pattern between hyperplastic, metaplastic and dysplastic or neoplastic cells. The differences in their staining patterns were quantitative and did not allow a qualitative differentiation between chronic pancreatitis and pancreatic carcinoma. We found coexpression of Le a and Le b antigens in 46/54 pancreatic specimens. All but 7 pancreata were CA 19-9 positive. An association between Le x, y and Le a, b antigen expression could not be noted in our material.

[Neuropathologic findings in 13 deceased patients with acquired immunologic deficiency syndrome]. / Neuropathologische Befunde bei 13 Verstorbenen mit erworbenem Immundefektsyndrom.

The neuropathological findings in 13 patients with the acquired immune deficiency syndrome (AIDS) and with AIDS related complex (ARC) are reported. Six patients presented with neurological symptoms, whereas autopsy revealed CNS involvement in nine cases. Four patients showed neither neurological nor neuropathological abnormalities. The most frequent neuropathological diagnoses were toxoplasma encephalitis (4 cases) and multiple or solitary cerebral necroses (3 cases). Long tract degeneration of the spinal cord was found in 2 cases. Cytomegalovirus infection, progressive multifocal leukoencephalopathy, primary lymphoma of the CNS, infiltration of the leptomeninges by plasmocytoma cells and a solitary metastasis of a bronchial carcinoma were diagnosed in one case each. Subacute leukoencephalitis, mentioned frequently in the literature, was not present in this material. In one case, however, status spongiosus and gliosis was found in the cortex and basal ganglia. As similar spongy changes can be seen in mice infected experimentally with retroviruses, a pathogenetic role of the human T-cell lymphotropic/leukaemia virus type III (HTLV-III) cannot be ruled out. Astrogliosis and hypertrophy of astrocytes were found in nine cases. Morphometrically, the number of astrocytes was significantly higher in AIDS patients than in control cases which were selected randomly on grounds of comparable age. Whether this finding bears some relationship with HTLV-III encephalopathy remains open to further investigation. Glial nodules were found in four cases; according to silver impregnation they were composed of microglial elements.

Spongiform encephalopathy in a patient with acquired immune deficiency syndrome (AIDS).

The histological and ultrastructural findings of subacute spongiform encephalopathy (SSE) are described in the cerebral cortex and basal ganglia of a homosexual patient who died with acquired immune deficiency syndrome (AIDS). It is suggested that SSE, beside the diffuse AIDS leukoencephalopathy, might be another morphological substrate of the AIDS dementia complex.

Purpura cerebri in gram-negative septicaemia. A histological and immunohistochemical study.

Two cases with brain purpura following Gram-negative septicaemia were examined morphologically and immunohistochemically. The brain lesions, including ball and ring haemorrhages, a few days old, with some microglial cells accumulated around the older foci, were restricted to the white matter. Immunohistochemically, scanty deposits of IgG, IgA and IgM mainly in the macrophages in brain, kidneys and lungs were found, whereas staining with antibodies directed against IgE and complement (C3, C4) remained negative. In the brain, immunoglobulin deposits were located mainly in the macrophages, furthermore, in and around the walls of a few intact (non-haemorrhagic) vessels; within the perivascular haemorrhagic foci no deposits could be demonstrated. The relevance of these observations to the pathogenesis of brain purpura is discussed.

[Autopsy findings in patients with acquired immunodeficiency syndrome]. / Autopsiebefunde bei Verstorbenen mit erworbenem Immundefektsyndrom.

We have evaluated the autopsies of 11 patients with HTLV III/LAV-infection. The clinical diagnosis was AIDS in 10 cases and AIDS related complex (ARC) in one case. The most common infectious disease was pneumocystis carinii pneumonia, occurring in 5 cases. 3 patients showed evidence of mycobacterial infections and another three showed cytomegalovirus infections. Kaposi's sarcoma was found in 4 and other malignancies in 3 cases. Our results are in agreement with the findings of other authors.