Jarle Norstein

Human Intestinal B‐Cell Blasts and Plasma Cells Express the Mucosal Homing Receptor Integrin α4β7

Interactions between homing receptors on circulating leucocytes and endothelial addressins regulate tissue‐specific cellular extravasation. Although integrin á4β7 appears to be the main receptor for guthoming T lymphocytes, less is known about molecules mediating mucosal B cell homing. Expression of integrin α4β7 on B lymphocytes, B cell blasts, and plasma cells in human gut‐associated lymphoid tissue (GALT; the Peyers patches and appendix) and lamina propria was studied by multi‐colour immunofluorescence applied on cryosections. Isolated mononuclear cells from the same tissue compartments were examined by flow cytometry and compared with peripheral blood B cells. Integrin α4β7 was expressed by IgA+ B cell blasts and plasma cells (CD38high) in the lamina propria, B cell blasts in GALT, and sIgD+ B lymphocytes in peripheral blood. In contrast, GALT sIgD+ B lymphocytes were negative or only weakly positive for α4β7. These results suggested that B lymphocytes down‐regulate αAβ7 upon extravasation in GALT but up‐regulate this integrin after antigen‐priming. Thus, α4β7 may be a homing receptor also for B cell blasts extravasating in the gut lamina propria, where this integrin is maintained on plasma cells, perhaps as a local retention factor.

Survival after resection for primary lung cancer: A population based study of 3211 resected patients

Background: Very few population based results have been presented for survival after resection for lung cancer. The purpose of this study was to present long term survival after resection and to quantify prognostic factors for survival. Methods: All lung cancer patients diagnosed in Norway in 1993–2002 were reported to the Cancer Registry of Norway (n = 19 582). A total of 3211 patients underwent surgical resection and were included for analysis. Supplementary information from hospitals (including co-morbidity data) was collected for patients diagnosed in 1993–8. Five year observed and relative survival was analysed for patients diagnosed and operated in 1993–9. Factors believed to influence survival were analysed by a Cox proportional hazard regression model. Results: Five year relative survival in the period 1993–9 was 46.4% (n = 2144): 58.4% for stage I disease (n = 1375), 28.4% for stage II (n = 532), 15.1% for IIIa (n = 133), 24.1% for IIIb (n = 63), and 21.1% for stage IV disease (n = 41). The high survival in stage IIIb and IV was due to the contribution of multiple tumours. Cox regression analysis identified male sex, higher age, procedures other than upper and middle lobectomy, histologies such as adenocarcinoma and large cell carcinoma, surgery on the right side, infiltration of resection margins, and larger tumour size as non-favourable prognostic factors. Conclusions: Survival was favourable for resected patients in a population based group including subgroups such as elderly patients, those with advanced stage, small cell lung cancer, tumours with nodal invasion, and patients with multiple tumours. These results question the validity of the current TNM system for lung cancer with regard to tumour size and categorization of multiple tumours.

Risk factors for 30-day mortality after resection of lung cancer and prediction of their magnitude

Background: There is considerable variability in reported postoperative mortality and risk factors for mortality after surgery for lung cancer. Population-based data provide unbiased estimates and may aid in treatment selection. Methods: All patients diagnosed with lung cancer in Norway from 1993 to the end of 2005 were reported to the Cancer Registry of Norway (n = 26 665). A total of 4395 patients underwent surgical resection and were included in the analysis. Data on demographics, tumour characteristics and treatment were registered. A subset of 1844 patients was scored according to the Charlson co-morbidity index. Potential factors influencing 30-day mortality were analysed by logistic regression. Results: The overall postoperative mortality rate was 4.4% within 30 days with a declining trend in the period. Male sex (OR 1.76), older age (OR 3.38 for age band 70–79 years), right-sided tumours (OR 1.73) and extensive procedures (OR 4.54 for pneumonectomy) were identified as risk factors for postoperative mortality in multivariate analysis. Postoperative mortality at high-volume hospitals (⩾20 procedures/year) was lower (OR 0.76, p = 0.076). Adjusted ORs for postoperative mortality at individual hospitals ranged from 0.32 to 2.28. The Charlson co-morbidity index was identified as an independent risk factor for postoperative mortality (p = 0.017). A prediction model for postoperative mortality is presented. Conclusions: Even though improvements in postoperative mortality have been observed in recent years, these findings indicate a further potential to optimise the surgical treatment of lung cancer. Hospital treatment results varied but a significant volume effect was not observed. Prognostic models may identify patients requiring intensive postoperative care.

Phenotypes of B and T cells in human intestinal and mesenteric lymph

BACKGROUND & AIMS Cells in lymph draining the human gut have not been characterized previously. The aim of this study was to phenotype B and T cells present in microlymphatics of Peyers pathces and in mesenteric lymph. METHODS The studies were conducted by multicolor immunohistochemistry, flow cytometry, and immunocytochemistry. RESULTS In decreasing order of frequency, microlymphatics in Peyers patches contained naive T (CD3+CD45RA+ alpha 4 beta 7low) and B (sIgD+CD20+ alpha 4 beta 7low) lymphocytes, memory T (CD45RO+ alpha 4 beta 7+) and B (sIgD-CD20+ alpha 4 beta 7+) lymphocytes, and B-cell blasts (CD19+CD38high alpha 4 beta 7high). Naive cells were usually positive for L-selectin, memory cells were either positive or negative, and B-cell blasts were usually negative. Mesenteric lymph contained naive T (approximately 60%) and B (approximately 25%) lymphocytes, memory T and B lymphocytes (approximately 10%), and B-cell blasts (approximately 2%). Cytospins confirmed these results and showed, in addition, that B-cell blasts contained cytoplasmic immunoglobulin (Ig) A, IgM, or IgG in overall proportions of 5:1: < 0.5. CONCLUSIONS Our results are similar to the phenotypes previously described in animal thoracic or mesenteric lymph. A fraction of the B cells stimulated in Peyers patches are near terminal differentiation (contain cytoplasmic Ig) before they enter peripheral blood. Many memory cells, and most if not all B-cell blasts entering lymph show an adhesion molecule profile (alpha 4 beta 7high L-selectin low) in keeping with the presumed phenotype of lymphoid cells destined for mucosal effector sites such as the gut lamina propria.

Major histocompatibility complex class II–dependent antigen presentation by human intestinal endothelial cells

BACKGROUND & AIMS In the normal gut, human intestinal microvascular endothelial cells (HIMECs) express major histocompatibility complex (MHC) class II molecules. Enhanced expression is found in chronic inflammation. We examined the cytokine regulation of MHC class II molecules and the associated invariant chain (Ii) in HIMECs and investigated whether such cells can process and present a complex protein antigen to T cells. METHODS Enzyme-linked immunosorbent assay, flow cytometry, immunoelectron microscopy, as well as T-cell activation assay with HIMECs and HLA-DR-restricted T-cell clones were employed. RESULTS In unstimulated HIMEC monolayers, HLA-DR, -DP, and -DQ and Ii were undetectable at the protein level, but interferon gamma (IFN-gamma) (100 U/mL) induced expression that peaked for DR after 2-3 days, for DP after 4-6 days, for DQ after 10-12 days, and for Ii after 2-3 days. Tumor necrosis factor alpha had no effect alone but enhanced class II expression in combination with IFN-gamma, most notably for DQ and DP. HLA-DR3-restricted and Mycobacterium tuberculosis heat shock 65-kilodalton-specific T-cell clones were activated to produce IFN-gamma in response to relevant antigen presented by IFN-gamma-treated HIMECs. This response was inhibited by blocking monoclonal antibody to HLA-DR and by chloroquine when compared to professional antigen-presenting cells, HIMECs activated T-cell clones quite efficiently. CONCLUSIONS These data suggest that microvascular endothelial cells can present complex protein antigens in the human gut.

EXPRESSION OF THE L1 ANTIGEN (CALPROTECTIN) BY TISSUE MACROPHAGES REFLECTS RECENT RECRUITMENT FROM PERIPHERAL BLOOD RATHER THAN UPREGULATION OF LOCAL SYNTHESIS: IMPLICATIONS FOR REJECTION DIAGNOSIS IN FORMALIN‐FIXED KIDNEY SPECIMENS

The L1 antigen (calprotectin) is present in circulating monocytes but is restricted to certain subsets of tissue macrophages. Its expression is significantly increased in inflammatory bowel disease, apparently because of newly recruited monocytes. In vitro experiments were performed to substantiate lack of L1 upregulation in tissue macrophages, thereby justifying the use of this marker to detect newly recruited cells. Its reliability was further evaluated by studying mononuclear cell infiltrates characteristic of acute kidney rejection. After pro‐inflammatory stimulation, monocytes matured in vitro (n=12) as well as adherent mononuclear cells from normal small intestinal mucosa (n=5) were examined for L1 expression by immunocytochemistry and by ELISA (cell lysates). In addition, peritubular mononuclear L1+ cells were examined by immunohistochemistry in routine biopsy specimens from transplanted kidneys with (n=11) or without (n=14) histopathologically diagnosed acute rejection. L1 was not upregulated in monocytes matured in vitro, nor in mucosal macrophages after stimulation with interferon‐γ, LPS, phorbol ester, or supernatant from activated leucocytes. In transplanted kidneys with signs of acute rejection, the fraction of L1+ macrophages was significantly increased (P<0·001). Because L1 is persistently downregulated in mature tissue macrophages and is formalin‐resistant, it identifies young infiltrating macrophages in routinely processed biopsy material. L1 should therefore be a valuable adjunct in the diagnosis of kidney rejection.

Is there an association between SV40 contaminated polio vaccine and lymphoproliferative disorders? An age–period–cohort analysis on Norwegian data from 1953 to 1997

Between 1955 and 1963, an estimated number of 150 million people in various parts of the world, including Norway, received poliomyelitis vaccine possibly contaminated with infectious simian virus 40 (SV40). Human studies have investigated the hypothesised association between SV40 and various cancers, but the results have so far been contradicting. The aim of the present study was to examine Norwegian cancer incidence data to assess a possible association between birth cohorts assumed to have been subjected to the vaccine and the incidence rate of lymphoproliferative disorders (excluding Hodgkins lymphoma), further subdivided into non‐Hodgkins lymphoma (NHL), lymphocytic leukemia and plasma cell neoplasms. Between 1953 and 1997, the incidence rate of lymphoproliferative diseases combined increased about 3‐fold in both males and females. Subgroup analysis showed that this increase was largely attributable to NHL. Age–period–cohort modelling of the subgroups, as well as of all groups combined, showed that the cohort effect was more prominent than the period effect. However, the variations in incidence patterns across the birth cohorts did not fit with the trends that would be expected if a SV40 contaminated vaccine did play a causative role. Thus, our data do not support the hypothesis of an association between the vaccine and any subgroup of lymphoproliferative diseases.