CD4-independent protective cytotoxic T cells induced in early life by a non-replicative delivery system based on virus-like particles

The relative immaturity of the neonatal immune system limits CD4(+) Th1 and cytotoxic T lymphocyte (CTL) responses, and represents a significant challenge for the development of vaccines against intracellular pathogens. In this report, we demonstrate the ability of a non-replicative delivery system based on parvovirus-like particles (VLP) to induce CTL responses in the neonatal period. A single immunization of 1-week-old BALB/c mice with recombinant VLP carrying a CD8(+) T cell determinant from lymphocytic choriomeningitis virus (VLP-LCMV) induced antigen-specific CD8(+) cytotoxic T cells that were similar to those elicited by adult immunization, as assessed by cytotoxic activity, interferon (IFN)-gamma secretion, cytotoxic precursor cell frequencies, in vitro avidity for antigen and protective activity against viral challenge. These CTL responses are elicited within 2 weeks of a single immunization, in the absence of adjuvant and independently of the presence and help of CD4(+) T cells, highlighting the potential of VLP as candidate vaccine vectors in early life.     

Coding haplotype analysis supports HCR as the putative susceptibility gene for psoriasis at the MHC PSORS1 locus

PSORS1, near HLA-C, is the major genetic determinant of psoriasis. We present genetic and structural evidence suggesting a major role for the HCR gene at the PSORS1 locus. Genotyping of 419 families from six populations revealed that coding single-nucleotide polymorphisms of HCR formed a conserved allele HCR*WWCC that associated highly significantly with psoriasis and with the HLA-Cw6 allele in all populations. Because of strong linkage disequilibrium between HLA-Cw6 and HCR*WWCC, the two genes could not be genetically distinguished by this sample size. However, the variant HCR allele was predicted to differ in secondary structure from the wild-type protein. HCR protein expression in lesional psoriatic skin differed considerably from that observed in normal skin. These results provide strong evidence for the HCR*WWCC allele as a major genetic determinant for psoriasis, probably by a mechanism impacting on keratinocyte proliferation.     

Inflammatory myofibroblastic tumour (inflammatory pseudotumour) of the breast. Clinicopathological and genetic analysis of a case with evidence for clonality.

Inflammatory myofibroblastic tumours (IMTs) were initially considered to be benign reactive processes, but cases with an unfavourable outcome have been reported. Moreover, clonal genetic alterations have recently been published in some cases, suggesting that IMT may represent a malignant neoplastic entity. This paper reports a case of IMT that developed in the mammary gland, an unusual site. The histological picture was characterized by a proliferation of spindle cells with little cellular atypia and rare mitoses, associated with a polymorphous inflammatory infiltrate. Their immunophenotype, characterized by the expression of vimentin, smooth muscle actin, and cytokeratins, corresponded to that of myofibroblasts. Cytogenetic analysis revealed the clonal nature of the lesion. The modal karyotype was 48, X, ins(2;X)(q34;p21.2p22.2), +7, del(9)(p23), +19. Including the present observation, a 9p deletion has now been found in three cases of IMT. These observations show that IMT may be a clonal neoplasm, even in sites different from deep soft tissues.     

Histological detection of minimal metastatic involvement in axillary sentinel nodes: a rational basis for a sensitive methodology usable in daily practice.

There is no consensus method for the histological analysis of axillary sentinel nodes (SN). This study aimed to (1) assess the rate of occult metastases in SN using large serial sectioning and immunohistochemistry (IHC), (2) evaluate whether occult metastases were predictive of metastases in the downstream axillary nodes, and (3) specify a methodology of analysis of SN that could be both sensitive and applicable in daily practice. One hundred three patients with breast carcinoma underwent SN biopsy and then axillary dissection. SN free of tumor at standard examination of one section were sectioned at six levels (150-microm intervals) and immunostained for cytokeratin. The number and localization of labeled metastatic cells (occult metastases) were recorded. In 29 of the 103 patients (28%), SN were found to be metastatic after standard examination. The SN of the remaining 74 patients were further analyzed using IHC. Occult metastases were detected in 35 of these patients (47.3%), leading to an overall SN involvement rate of 62% (29+35/103). In 33 of these 35 cases, the plurality and the dispersion of the immunostained cells implied that the screening of only 3 of the 6 levels would have led to the detection of diagnostic positive events. Only one of the 35 patients (2.8%) with occult metastases showed metastatic lymph node in the downstream axilla. In our series of axillary SN, the analysis of one standard histologic section and, when negative, of only three additional sections after IHC revealed >60% of metastasis or occult metastasis. Metastasis detected by standard analysis had a high predictive value of downstream node metastasis, whereas the predictive value of occult metastasis revealed by IHC was poor. The clinical significance of occult metastases in SN needs to be specified by long-term follow-up analysis.     

A novel logistic model based on clinicopathological features predicts microsatellite instability in colorectal carcinomas.

High-frequency microsatellite instability has been reported to be associated with good prognosis in colorectal adenocarcinoma. However, methods to assess microsatellite instability (MIN) are based on genetic assays and are not ideally suited to most histopathology laboratories. The aim of the present study was to develop a model for prediction of MIN status in colorectal cancer based on phenotypic characteristics. Clinicopathological features of a cohort of 204 patients with primary colon cancer were retrospectively reviewed following predetermined criteria. Genetic assessment of MIN status was performed on DNA extracted from sections of formalin-fixed, paraffin-embedded specimens by testing a panel of 11 microsatellite markers. Logistic regression analysis generated a mathematical tool capable of identifying colorectal tumors displaying MIN status with a sensitivity of 77.8% and a specificity of 96.8%. Features associated with instability included the proximal location of the lesions, occurrence of solid and/or mucinous differentiation, absence of cribriform structures, presence of peritumoral Crohn-like reaction, expansive growth pattern, high Ki67 proliferative index, and p53-negative phenotype. This approach predicts microsatellite instability in colorectal carcinoma with an overall assigned accuracy of 95.1% and a negative predictive value of 97.8%. Implementation of this tool to routine histopathological studies could improve the management of patients with colorectal cancer, especially those presenting with stage II and III of the disease. It will also assist in identifying a subset of patients likely to benefit from adjuvant chemotherapy.     

Bilirubin-adsorption in 23 critically ill patients with liver failure

PURPOSE: Previous studies suggest that high levels of bilirubin exert cytotoxic, neurotoxic and encephalopathic effects that themselves may lead to further deterioration of liver function and multiorgan failure. Although extracorporeal BA is not a causal therapy, there are case reports of clinical benefits of BA. The present retrospective study investigated the clinical utility and effectiveness of BA in 23 patients with liver failure. METHODS: Twenty-three patients (61+/-11 years) with excessive hyperbilirubinemia (>25 mg/dL) after liver transplantation (n=7), partial liver resection (n=12) and others (n=4) were treated with BA (3.6 liters plasma per BA, BR350, Asahi) and followed for 45+/-8 days. RESULTS: A mean of 6.6 treatments (3-16) were performed per patient. On average, a single BA treatment reduced bilirubin-levels from 31+/-12 to 23.7+/-9 mg/dL (p<0.001). Levels of bile acid were reduced from 41.8+/-6 to 33.5+/-5 mg/dL. The 30-day mortality was 50%. BA was able to halt and stabilize the progressive increase in bilirubin levels in all patients. In contrast to survivors, non-survivors were characterized by a repeated rapid rise in bilirubin levels after cessation of BA treatment. CONCLUSIONS: BA is able to stabilize or decrease bilirubin levels in patients with liver failure. Our experience suggests that BA is a safe and promising short-term treatment option for patients with acute deterioration of hepatic function.     

Influence of various alginate brands on the redifferentiation of dedifferentiated bovine articular chondrocytes in alginate bead culture under high and low oxygen tension

We examined the influence of various alginates on the redifferentiation of dedifferentiated articular chondrocytes in alginate bead culture under low (5%) and (21%) high oxygen supply. Isolated bovine articular chondrocytes were dedifferentiated and multiplied by 2-week monolayer culture under 21% oxygen. They were subcultured at a density of 10(7) cells/mL in six different commercially available sodium alginates (1.2%, w/v) and held under 21 or 5% oxygen for 3 weeks. Proliferation (DNA measurement on days 0 and 21 of culture), collagen type II production (immunocytochemistry and Western blotting), and [(3)H]proline and [(35)S]sulfate incorporation were monitored. Collagen type II production was significantly stronger under 5% oxygen compared with 21% oxygen in two alginates (three other alginates nearly reached the significance level). However, alginate-based differences proved not to be significant. [(3)H]Proline incorporation was not influenced by alginate but showed strong oxygen dependency (up to 3-fold higher under 5% oxygen). For [(35)S]sulfate incorporation oxygen dependency was even stronger (up to 8-fold higher under 5% oxygen) and significant alginate-dependent differences were found for several alginates. The effects of the different alginates did not correlate with their pH, viscosity, or guluronic:mannuronic acid ratio. Thus, the type of alginate and even more, the oxygen supply, influence the redifferentiation and matrix production of dedifferentiated bovine articular chondrocytes.     

Antibody response after RSV infection in children younger than 1 year of age living in a rural area of Mozambique

Serological responses have been studied in respiratory syncytial virus (RSV) infected children < 1 year of age attending the outpatient department of the Manhiça District Hospital (Mozambique). Molecular characterization of viral RNA in nasopharyngeal aspirates from the infected children indicated a high level of genetic uniformity among the infecting viruses, all of which belonged to a single genotype of RSV group A. A representative virus strain, Moz00, was isolated from one of the infants and was used, together with the group A strain A2 and the group B strain 8/60, as antigens in the quantification of infant antibody responses. In this study, 97.5% (39/40) and 96.4% (27/28) of infected children produced an antibody response against Moz00 detected by the membrane fluorescent antibody test (MFAT) and the neutralization test (NT), respectively. Seroconversion rates decreased when the A2 and 8/60 strains were used as antigen in MFAT (95.4% and 88.2%, respectively) or NT (81.8% and 54.5%, respectively), indicating that antibody responses had both group‐ and strain‐specific components. Antibodies in convalescent sera of infected children were compared with maternally derived antibodies detected in a group of children also < 1 year of age, but with no evidence of RSV infection. The convalescent sera exhibited reduced neutralizing capacity when the 8/60 strain was used as antigen (P = 0.028), suggesting that the infant antibody response lacks neutralizing capacity against strains of the heterologous virus group. Restricted cross‐reactivity and neutralizing capacity of antibodies generated by young children might be expected to induce only moderate protection in subsequent epidemics against genetically distant strains. J. Med. Virol. 69:579–587, 2003. © 2003 Wiley‐Liss, Inc.     

Classification of B-cells according to their differentiation status, their micro-anatomical localisation and their developmental lineage

B-lymphocytes or B-cells form a diverse and flexible repertoire of immune cells that are reactive to almost all potential pathogens by means of the production of antigen-specific immunoglobulins. They can be divided into different populations or subsets, characterised by a distinct combination of properties. These subsets are identified on the base of their differentiation status (precursor B-cells, peripheral B-cells), their localisation in the micro-anatomical compartments of the B-cell follicle (marginal zone B-cells, lymphocytic corona B-cells, follicle centre B-cells), and the developmental lineage to which they belong (B-1 cells, and B-2 or conventional B-cells). The latter classification of B-cells into B-1 cells and B-2 cells is commonly followed by immunologists, mainly in the study of mice models, while pathologists and haematologists tend to use a terminology for B-cells which refers to their localisation in the micro-anatomical compartments of the B-cell follicle and/or differentiation status. In this review, we will discuss the various subsets of B-cells and point to the similarities between the various classification systems in use.