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Peripheral mechanisms preventing autoimmunity and maintaining tolerance to commensal microbiota involve [CD4.sup.+] [Foxp3.sup.+] regulatory T ([T.sub.reg]) cells (1,2) generated in the thymus or extrathymically by induction of naive [CD4.sup.+] [Foxp3.sup.-] [...]

Our innate immune system distinguishes microbes from self by detecting conserved pathogen-associated molecular patterns (1). However, these are produced by all microbes, regardless of their pathogenic potential. To distinguish virulent [...]

This review describes the mechanisms of the immune response to meningococcal disease, examining the extent to which individual variation of the immune response can determine susceptibility. It concludes by summarising [...]

The pathogenesis of tuberculosis involves multiple phases and is believed to involve both a carefully deployed series of adaptive bacterial virulence factors and inappropriate host immune responses that lead to tissue damage. A defined Mycobacterium tuberculosis mutant strain lacking the sigH-encoded transcription factor showed a distinctive infection phenotype. In resistant C57BL/6 mice, the mutant achieved high bacterial counts in lung and spleen that persisted in tissues in a pattern identical to those of wild-type bacteria. Despite a high bacterial burden, the mutant produced a blunted, delayed pulmonary inflammatory response, and recruited fewer CD[4.sup.+] and CD[8sup.+] T cells to the lung in the early stages of infection. In susceptible C3H mice, the mutant again showed diminished immunopathology and was nonlethal at over 170 days after intravenous infection, in contrast to isogenic wild-type bacilli, which killed with a median time to death of 52 days. Complete genomic microarray analysis revealed that M. tuberculosis sigh may mediate the transcription of at least 31 genes directly and that it modulates the expression of about 150 others; the Sigh regulon governs thioredoxin recycling and may be involved in the maintenance of intrabacterial reducing capacity. These data show that the M. tuberculosis sigh gene is dispensable for bacterial growth and survival within the host, but is required for the production of immunopathology and lethality. This phenotype demonstrates that beyond an ability to grow and persist within the host, M. tuberculosis has distinct virulence mechanisms that elicit deleterious host responses and progressive pulmonary disease.

In schistosomiasis mansoni, parasite eggs precipitate an intrahepatic granulomatous and fibrosing inflammatory process, which is mediated by, and dependent on, MHC class II-restricted CD4 T helper (Th) lymphocytes specific for schistosome egg antigens (SEA). In the mouse model of the disease, CBA mice develop large granulomas, whereas in C57BL/6 (BL/6) mice these granulomas are significantly smaller. To further investigate how the prevailing cytokine environment influences the development of the egg-induced immunopathology, we immunized the low-pathology BL/6 mice with SEA in complete Freund's adjuvant (CFA) once before, and once again during, the course of a 7-week infection. This immunization caused a pronounced Th1 shift in the SEA-specific CD4 T cell response, which was detected in the mesenteric lymph nodes (MLNs) and spleens, as well as in the granulomatous lesions themselves. The immunized mice displayed a dramatic enhancement of hepatic egg-induced immunopathology manifested by a marked increase in granuloma size and parenchymal inflammation, leading to early death. Control mice immunized with equivalent amounts of SEA or CFA alone displayed the smaller hepatic lesions in a Th2-dominant environment typically seen in the unimmunized BL/6 mice. Analysis of granuloma and MLN lymphocytes from the SEA/CFA-immunized mice revealed that the proportion of CD4 T cells was unchanged in comparison with the control BL/6 groups and remained significantly lower than that seen in the normally high-pathology CBA strain. These results suggest that the shift toward Th1-type cytokine production by a numerically stable population of CD4 T cells correlates with severe exacerbation of immunopathology in schistosomiasis.

Macrophage-stimulating protein (MSP) is a member of the hepatocyte growth factor-scatter factor (HGF-SF) family. Labeled MSP bound to Madin-Darby canine kidney (MDCK) cells transfected with complementary DNA encoding Ron, a cell membrane protein tyrosine kinase. Cross-linking of [I.sup.125]-labeled MSP to transfected cell (MDCK-RE7 cells) and immunoprecipitation by antibodies to Ron revealed a 220-kilodalton complex, a size consistent with that of MSP (80 kilodaltons) cross-linked to the β chain of Ron (150 kilodaltons). The binding of [I.sup.25]-labeled MSP to MDCK-RE7 cells was inhibited by unlabeled MSP, but not by HGF-SF. MSP caused phosphorylation of the β chain of Ron and induced migration of MDCK-RE7 cells. These results establish the ron gene product as a specific cell-surface receptor for MSP., Macrophage-stimulating protein (MSP) is an 80-kD disulfide-linked serum protein that induces the responsiveness of murine peritoneal resident macrophages to chemoattractants[1]. MSP also acts directly as a chemoattractant for resident macrophages[2], [...]

* Context.--Diagnosis and classification of primary intraocular lymphoma can be challenging because of the sparse cellularity of the vitreous specimens. Objective.--To classify and clinically correlate intraocular lymphoma according to the World Health Organization (WHO) classification by using vitrectomy specimens. Design.--Clinical history, cytologic preparations, flow cytometry reports, and outcome of 16 patients diagnosed with intraocular lymphoma were reviewed. Results.--The study group included 10 women and 6 men. The mean age of the patients was 63 years (range, 19-79 years). Eleven patients had central nervous system involvement and 6 patients had systemic involvement. All cases were adequately diagnosed and classified according to the WHO classification by using combination of cytologic preparations and 4-color flow cytometry with a limited panel of antibodies to CD19, CD20, CD5, CD10, and [kappa] and [lambda] light chains. The cases included 9 primary diffuse large B-cell lymphomas of the CNS type; 2 diffuse large B-cell lymphomas, not otherwise specified; 1 extranodal, low-grade, marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT); 1 precursor B-lymphoblastic lymphoma; and 3 peripheral T-cell lymphomas, not otherwise specified. Of note, all 11 cases of diffuse large B-cell lymphoma were [CD10.sup.-]. All the patients received systemic chemotherapy and radiation therapy. Only 4 patients were free of disease at last follow-up (range, 18 months to 8 years), with severe visual loss. Conclusions.--Intraocular lymphoma cases can be adequately classified according to the WHO classification. Diffuse large B-cell lymphoma, [CD10.sup.-] and most likely of non-germinal center B-cell-like subgroup, is the most common subtype of non-Hodgkin lymphoma in this site, in contrast to ocular adnexal lymphoma for which MALT lymphoma is the most common subtype. (Arch Pathol Lab Med. 2009;133:1233-1237), Primary intraocular lymphoma (PIOL), considered part of primary central nervous system lymphoma (PCNSL), is a rare type of non-Hodgkin lymphoma. Primary intraocular lymphoma is a unique, malignant lympho-proliferation because of [...]

* Retinoblastoma is the most common primary intraocular tumor of childhood and may be heritable or occur sporadically. Anterior diffuse retinoblastoma is an uncommon variant that is thought to be sporadic. We describe a child with anterior diffuse retinoblastoma who presented with a pseudohypopyon. Genetic analysis showed a germline mutation of the RB1 allele that is potentially heritable. Immunofluorescence staining was positive for transforming growth factor P and for vascular endothelial growth factor and negative for inducible nitric oxide synthase and for hypoxia inducible factor a in the tumor seeds, indicating acquisition of nonischemia-mediated survival factors of the tumor seeds in the aqueous humor. (Arch Pathol Lab Med. 2009;133:1215-1218), Retinoblastoma is the most common primary intraocular tumor in childhood. When a family history is present, 50% of offspring of a parent carrying an RB1 mutant allele will inherit that [...]

* Context.--Tumor necrosis factor a, interleukin 6, and interleukin 8 serum/plasma levels are frequently used for the monitoring of patients with systemic immune activation/ sepsis. This requires comparability of test results over time. However, cytokines are usually not considered to be very stable after blood collection, which might artificially interfere with test results. Objective.--To obtain better knowledge about stability of these cytokines in blood samples for interpretation of test results. Design.--Blood of patients with systemic immune activation was collected in EDTA, lithium heparin, ammonium heparin, and serum tubes. Aliquots were analyzed after storage at room temperature for 2 to 8 hours. Additionally, storage conditions for separated serum/plasma for 24 hours and the reproducibility of repeated cytokine measurements by an automated DPC Immulite analyzer were tested. Results.--Tumor necrosis factor a level was stable in EDTA plasma for 8 hours, while slightly increasing in heparin plasma and serum. Interleukin 6 concentrations were stable for 8 hours in all blood types, whereas interleukin 8 concentrations were stable only in EDTA plasma and were strongly increasing in heparin plasma and serum. Cytokine concentrations in separated serum/plasma were stable during 24 hours if stored at 4[degrees]C or frozen at -20 or -70[degrees]C. Reproducibility of repeated cytokine measurements revealed no significant differences for all blood types. Conclusions.--Cytokine levels were most critically influenced by the period between blood collection and plasma separation, but its impact was strongly dependent on cytokine and anticoagulant. However, under appropriate conditions cytokine levels were surprisingly stable for up to 8 hours., Diagnostic analysis of cytokine levels in serum or plasma has become an important issue for several disease conditions. Especially in cases of systemic inflammation/sepsis, several cytokines, such as tumor necrosis [...]

* Context.--In comparison to [alpha][beta] T cells, little is known about the immunophenotype of healthy peripheral blood [gamma][delta] T cells or about conditions associated with expansion of this usually minor T-cell subset. Objective.--To study the immunophenotype of increased nonneoplastic peripheral blood [gamma][delta] T cells and to determine clinical conditions associated with this laboratory finding. Design.--Flow cytometric T-cell phenotyping studies performed on 352 consecutive peripheral blood specimens were reviewed, and 62 cases (18%) in which [gamma][delta] T cells comprised either more than 5% of the total lymphocytes or had an absolute count of more than 200 cells per [micro]L or both, were studied further. Clinical data were available from 36 cases. Results.--The [gamma][delta] T cells often had an immunophenotype distinct from the [alpha][beta] T cells, with differences in CD5 expression as the most common (n = 17), followed by differences in CD3 (n = 6) and CD7 (n = 3). CD16 coexpression by the [gamma][delta] T cells was also frequent (n = 20). In 28 (78%) of 36 cases, there were one or more associated conditions: infection/inflammatory disease (n = 18), autoimmune disease (n = 9), lymphoproliferative disorder (n = 6), and splenectomy (n = 3). Conclusions.--Circulating [gamma][delta] T cells are immunophenotypically distinct from ap T cells, and mild increases in these cells are not uncommon and may be associated with immune system activation and splenectomy. Recognition of this phenomenon is important because reactive [gamma][delta] T cells can exhibit distinctive immunophenotypic features that are also encountered in neoplastic conditions, such as T-cell large granular lymphocytic leukemia., Early in their ontogeny, T cells commit to express either [alpha][beta] or [gamma][delta] T-cell receptor (TCR) heterodimers, resulting in phenotypically and functionally distinct T-cell lineages. (1) In healthy adults, [alpha][beta] [...]

Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma with a poor prognosis that may be confused with less aggressive diseases, such as small lymphocytic lymphoma and follicular lymphoma. In many cases immunophenotyping, particularly analysis of reactivity for CD5 and CD10, is an important adjunct to morphology that usually distinguishes MCL from follicular lymphoma; the former is [CD5.sup.+]/[CD10.sup.-], whereas follicular lymphoma is the reverse. We report a case of MCL, initially diagnosed as follicular lymphoma, that at presentation expressed neither CD5 nor CD10. At relapse, it was still [CD5.sup.-], but CD10 was now detected. Studies for a t(11;14) translocation and CYCLIN D1 protein expression, however, permitted a revised diagnosis of MCL. An MCL with this immunophenotype and classical morphology has not been previously reported., Mantle cell lymphoma (MCL) is a moderately aggressive B-cell non-Hodgkin lymphoma (NHL) that was first distinguished in the 1990s from morphologically similar lymphomas, such as small lymphocytic lymphoma (SLL) and [...]

Context.--The immunophenotypic profile of basophils is not yet fully established, and the immunophenotypic changes in chronic myelogenous leukemia are not fully characterized. Objective.--To establish a comprehensive immunophenotypic spectrum of normal basophils and to assess the range of immunophenotypic aberrations of basophils in chronic myelogenous leukemia. Design.--Using 4-color flow cytometry, we compared the immunophenotypic profile of basophils in peripheral blood or bone marrow samples from 20 patients with no evidence of neoplasia to basophils from 15 patients with chronic myelogenous leukemia. Results.--Basophils in control cases were all positive for CD9, CD13, CD22, CD25 (dim), CD33, CD36, CD38 (bright), CD45 (dimmer than lymphocytes and brighter than myeloblasts), and CD123 (bright), and were negative for CD19, CD34, CD64, CD117, and HLA-DR. Basophils in all chronic myelogenous leukemia patients possessed 1 to 5 immunophenotypic aberrancies. The most common aberrancies were underexpression of CD38, followed by aberrant expression of CD64 and underexpression of CD123. CD34 and CD117 were present in cases with basophilic precursors. Myeloblasts showed a distinct immunophenotypic profile, as they typically expressed CD34 and CD117, showed dimmer expression (compared with basophils) of CD38, CD45, and CD123, and lacked expression of CD22. Conclusions.--Flow cytometric immunophenotyping can identify immunophenotypic aberrations of basophils in chronic myelogenous leukemia, and discriminate basophils from myeloblasts., Basophils are the least common blood granulocytes, with a prevalence of about 0.5% of total leukocytes and about 0.3% of nucleated marrow cells in a healthy individual, (1,2) and acute [...]

Context.--In the diagnosis of lymphomas and leukemias, flow cytometry has been considered an essential addition to morphology and immunohistochemistry. The interpretation of immunophenotyping results by flow cytometry involves pattern recognition of different hematologic neoplasms that may have similar immunologic marker profiles. An important factor that creates difficulty in the interpretation process is the lack of consistency in marker expression for a particular neoplasm. For this reason, a definitive diagnostic pattern is usually not available for each specific neoplasm. Consequently, there is a need for decision support tools to assist pathology trainees in learning flow cytometric diagnosis of leukemia and lymphoma. Objective.--Development of a Web-enabled relational database integrated with decision-making tools for teaching flow cytometric diagnosis of hematologic neoplasms. Design.--This database has a knowledge base containing patterns of 44 markers for 37 hematologic neoplasms. We have obtained immunophenotyping data published in the scientific literature and incorporated them into a mathematical algorithm that is integrated to the database for differential diagnostic purposes. The algorithm takes into account the incidence of positive and negative expression of each marker for each disorder. Results.--Validation of this algorithm was performed using 92 clinical cases accumulated from 2 different medical centers. The database also incorporates the latest World Health Organization classification for hematologic neoplasms. Conclusions.--The algorithm developed in this database shows significant improvement in diagnostic accuracy over our previous database prototype. This Web-based database is proposed to be a useful public resource for teaching pathology trainees flow cytometric diagnosis. (Arch Pathol Lab Med. 2008;132:829-837), The use of flow cytometry in immunophenotyping has undoubtedly added an essential dimension to the diagnosis of hematologic neoplasms. (1,2) Hematologic cells express a wide range of cell surface and [...]

A study of the evolutionary causes and effects of immunopathology is presented. The evolution of strategies for parasite virulence and host resistance might be shaped by immunity and future work might reveal whether immunopathology constrains the evolution of resistance in all host taxa.

Research has been conducted on Salmonella interactions with the host. The authors have determined cytokine levels including pro-inflammatory cytokines produced after the invasion of host range serotypes Salmonella typhimurium and S. enteritidis and host-specific serotype S. gallinarum into chicken cells in vitro, and have described the mechanisms of immunopathogenesis of salmonellosis in chicken.

Multiple sclerosis, a disorder of the central nervous system (CNS), is characterized by damage to myelin, the insulating membrane that surrounds nerve fibres. The lesions found in multiple sclerosis are [...]

Abstract. When injected into mice, the synthetic double-stranded polynucleotide poly(inosinic) * poly(cytidylic) acid induces high natural killer (NK) cell activity within 4 to 12 hours. Induction of NK activity in […]

T-Cell Tumor Elimination as a Result of T-Cell Receptor--Mediated Activation ACTIVATION OF NORMAL RESTING Tlymphocytes leads to a cascade of events that culminates in entry into the cell growth cycle [...]

Tumor necrosis factor (TNF), a cytokine, can produce egg granulomas and the schistosomes, the parasitic worms that cause schistosomiasis, employ host TNF alpha to stimulate reproduction. Researcher P. Amiri and colleagues found that the schistosome pathogens are able to use TNF when T and B lymphocytes, which form part of the body's immune system, are not present. These findings may lead the way to more research on the co-evolution of parasites and host cytokine responses.

Induction of Suppressor Cells Specific for AChR in Experimental Autoimmune Myasthenia Gravis THE BASIC ABNORMALITY IN MYASTHENIA gravis is a reduction in the number of acetylcholine receptors (AChR's) at neuromuscular [...]

Research was conducted to examine the role of T lymphocytes in host responses to sublethal systemic infection with Candida albicans using mAb depletion of CD4+ and CD8+ cells from CBA/CaH and BALB/c mice which develop severe and mild tissue damage, respectively. Results reveal that both CD4+ and CD8+ lymphocytes contribute to the reduction of tissue damage after systemic infection with C. albicans. Findings also provide evidence that the development and expression of CD4+ lymphocyte effector function is influenced by the genetic background of the mouse.