Possible role of L-selectin in T lymphocyte alveolitis in patients with active pulmonary sarcoidosis

A number of adhesion molecules participate in the recruitment of inflammatory cells to the site of inflammation, and selectins together with their ligands are important in the early transient adhesion phase. In this study, we evaluated the role of L-selectin in T lymphocyte alveolitis in patients with active pulmonary sarcoidosis. We measured serum and bronchoalveolar lavage fluid (BALF) concentrations of soluble (s)L-selectin using an ELISA. Serum and BALF concentrations of sL-selectin were significantly elevated in patients with sarcoidosis compared with control healthy subjects and idiopathic pulmonary fibrosis (IPF) patients (P < 0.05 and P < 0. 01, respectively). The lymphocyte surface marker was also examined in peripheral blood and BALF by flow cytometric analysis. The percentage of CD3+CD62L+ cells (L-selectin-bearing T lymphocytes) was significantly lower in peripheral blood of sarcoidosis than in that of healthy subjects (P < 0.01). In contrast, the percentage of CD3+CD62L- cells (L-selectin-negative T lymphocytes) in BALF of patients with sarcoidosis was significantly higher than in healthy subjects (P < 0.05) and IPF patients (P < 0.01). Furthermore, there was a significant correlation between serum concentrations of sL-selectin and the number of L-selectin-negative T lymphocytes in BALF (r = 0.535, P < 0.01). Our results suggest that L-selectin may be involved in T lymphocyte alveolitis in patients with active pulmonary sarcoidosis.     

Evidence for extrathymic T cell maturation after thymectomy in infancy

Our previous study showed that children who had been partially or completely thymectomized during heart surgery as infants had lower proportions and numbers of total lymphocytes and reduced proportions of T cells (CD3(+)), helper T cells (CD4(+)) and naive T cells (CD3(+) CD4(+) CD45RA(+)), but normal proportion of cytotoxic T cells (CD8(+)). In this study T lymphocytes from a selected group of eight of these children and age- and gender-matched controls were characterized further using flow cytometry to determine phenotypes of T cells and T cell subsets related to T cell regulation and phenotypes suggestive of extrathymic maturation. Immune function was assessed by measuring autoantibodies and antibodies against vaccines. The study group had significantly lower numbers of all the main subsets of T lymphocytes and the composition was different. Thus, the proportions of lymphocytes with the following phenotypes: CD3(+), CD2(+), CD7(+), CD4(+), CD62L(+), CD4(+) CD62L(+) and CD4(+) CD69(-) were significantly reduced in the study group compared with the control group, but significantly higher proportions were seen of lymphocytes expressing CD8alpha(+) CD8beta(-) and TCRgammadelta(+) CD8alpha(+) CD8beta(-). The absolute number and proportion of CD4(+) CD25(+) cells were reduced but the proportions of the subgroup of naive regulatory T cells (CD4(+) CD25(+) CD62L(+)) and non-activated regulatory T cells (CD4(+) CD25(+) CD69(-)) were not reduced in the thymectomized children. We conclude that the phenotypic characteristics of T lymphocytes of children who have lost their thymus in infancy are indicative of extrathymic maturation. T regulatory cells appear to be less affected than other subsets by the general reduction in T cell numbers.     

艾滋病患者T淋巴细胞表面归巢分子的表达在抗病毒治疗后升高

目的 探讨艾滋病(AIDS)患者高效抗反转录病毒治疗(HAART)前后T淋巴细胞表面归巢分子CD49d、CCR9、CD62L表达的变化情况.方法 采用流式细胞术检测42例艾滋病患者和18例HIV阴性健康对照的外周血T淋巴细胞表面CD49d、CCR9和CD62L表达,用BD FACSDiva软件分析计算各组细胞表达的百分率.结果 治疗后组外周血的平均CD4~+T淋巴细胞明显高于治疗前组(P<0.01);治疗前组CD3~+CD49d~+、CD3~+ CCR9~+、CD3~+CD62L~+、CD3~+CD4~+、CD4~+CD49d~+、CD4~+CCR9~+、CIM~+CD62L~+、CD8~+CD49d~+、CD8~+CD62L~+T淋巴细胞的百分率显著低于治疗后组和阴性对照组(P<0.05);CD3~+CD8~+T淋巴细胞的百分率高于治疗后组(P<0.05).治疗后组CD3~+CCR9~+、CD8~+CCR9~+、CD8~+CD62L~+T淋巴细胞的百分率均低于阴性对照组(P均<0.001).结论 AIDS患者外周血T淋巴细胞亚群不仅比例失调,而且其表面表达肠道归巢分子CD49d、CCR9,淋巴结归巢分子CD62L的数量发生异常改变.抗病毒治疗可以逆转以上部分免疫病理变化.建议肠道归巢分子CD49d、CCR9和淋巴结归巢分子CD62L可作为艾滋病疾病进展和评价机体HAART后免疫重建的指标.     

Analysis of circulating gammadelta T cells in children affected by IgE-associated and non-IgE-associated allergic atopic eczema/dermatitis syndrome

Recent studies have suggested that not only alphabeta(+) T cells, but also the less common gammadelta(+) T cells may play a role as effectors and immunoregolatory cells in the development and perpetuation of allergic inflammation. The objective of this study was to focus on the role of gammadelta(+) T cells in atopic dermatitis (AD), a chronic relapsing inflammatory disease of the skin, often associated with allergic bronchial asthma. The present study employed flow cytometric analysis to compare numbers and phenotypic characteristics of gammadelta(+) T cells in the peripheral blood of children with atopic dermatitis and age-matched healthy controls. The percentage of circulating Vgamma 9Vdelta2(+) T lymphocytes was significantly increased in AD patients with respect to the age-matched controls, with a positive correlation with clinical score severity. The prevalent phenotype in both AD patients and controls was CD45RO(+), with no differences observed in the percentage of Vdelta2(+) CD45RO(+) between these groups. Conversely, memory CD45RO(+) CD62L(+) Vdelta2(+) lymphocytes were significantly lower in AD patients. Furthermore, naive circulating Vdelta2(+) T lymphocytes were significantly lower in AD children than in aged-matched controls. No correlation was observed between circulating Vgamma 9Vdelta2(+) expansion and IgE serum levels. It was concluded that an association exists between the levels of circulating gammadelta(+) T lymphocytes and atopic dermatitis, with a positive correlation with clinical score but no link with IgE serum levels. The pathophysiological role of gammadelta T lymphocytes in atopic dermatitis awaits further investigation.     

Marked increase in L-selectin-negative T cells in neonatal pertussis. The lymphocytosis explained?

The detailed immunophenotype of peripheral blood lymphocytes from a neonate with pertussis was determined by flow cytometry and compared with results from cord blood from healthy newborns. Most (72%) of the lymphocytes were CD3+ T cells with a normal CD4/CD8 ratio (2.5). The T cells were largely HLA-DR negative and CD45RA+, consistent with unstimulated na?ve T cells. Almost all of the CD4+ T cells were Leu8 (L-selectin, CD62L) negative, while almost all of the CD8+ T cells were CD28+. There was no increase in CD7- CD4+ T cells (Th2-like). No relative increase in CD16/56+ NK cells (5%) or CD19/20+ B cells was seen. The most dramatic finding in this case was the remarkable lack of expression of L-selectin by the T cells. L-selectin expression is associated with homing of peripheral blood lymphocytes to lymph nodes. The dramatic reduction in L-selectin expression of the T lymphocytes in pertussis, perhaps induced by pertussis toxin, likely prevents homing of the T cells to peripheral lymphoid tissues and provides a likely explanation for the marked lymphocytosis noted in this disease.     

CD40-CD40L在强直性脊柱炎患者外周血淋巴细胞上的表达

目的探讨共刺激分子CD40CD40L在强直性脊柱炎(AS)患者的外周血淋巴细胞亚群上的异常表达与免疫功能紊乱的关系。方法用流式细胞仪采用直接免疫荧光法测定30例AS患者和20例健康对照人外周血淋巴细胞表面标志CD3、CD4、CD8、CD19的表达情况,CD40L在CD4 T和CD8 T细胞上的表达及CD40在CD19 B细胞上的表达。用速率散射比浊法测定血清中免疫球蛋白IgG,IgA和IgM的水平。结果①AS患者CD3 、CD3 CD4 、CD19 细胞较正常对照组显著增高(P<0.05),CD3 CD8 细胞较正常对照组显著降低(P<0.05);②AS患者CD4 T细胞和CD8 T细胞上的CD40L、CD19 B细胞上CD40的表达都较对照组显著增高(P<0.05);③AS患者血清中2种免疫球蛋白IgG、IgA的水平均较对照组显著增高(P<0.05)。结论CD40CD40L途径在AS免疫功能紊乱中起了重要作用。     

Targeting CD45RB alters T cell migration and delays viral clearance

CD45 is a receptor tyrosine phosphatase essential for TCR signaling. One isoform, CD45RB, is down-regulated in memory cells and targeting CD45RB with a specific antibody has been shown to inhibit graft rejection. Its role in immunity to infection, however, has not been tested. Here, we report the effect of anti-CD45RB antibody treatment on the induction of anti-influenza CD8+ T cells and viral clearance. Anti-CD45RB-treated mice had delayed pulmonary viral clearance compared with untreated mice whose infection was completely cleared by day 8 post-infection. In anti-CD45RB-treated mice, the total CD4+ and CD8+ T cell numbers in both the lungs and mediastinal nodes were substantially reduced at days 5 and 8; this effect was less marked for the spleen. CD8+ T cells specific for influenza virus were also reduced compared with the control group in all three organs at day 8. By day 11, when both treated and control groups showed no virus remaining in the lungs, specific CD8+ T cell numbers were at similar low levels. Homing to lymph nodes and lung of dye-labeled T cells was greatly inhibited (by >80%) by anti-CD45RB treatment. This reduced homing corresponded with reduced CD62L and beta1-integrin expression in both uninfected and infected mice. Since CD62L plays a critical role in homing lymphocytes to lymph nodes, and high levels of CD62L and alpha4beta1-integrin are expressed by lymphocytes that home to bronchus-associated lymphoid tissue, we suggest that reduced expression of these molecules is a key explanation for the delay in immune responses.     

Anti-phospholipid antibodies and CD5+ B cells in HIV infection

This cross-sectional study evaluates the correlation between anti-phospholipid antibodies and CD5+ B cells in 110 patients infected with HIV-1. There were 89.1% of the patients who had IgG antibodies against cardiolipin and phosphatidylserine. The prevalence of IgM and IgA antibodies was < 22%. AIDS was associated with lower frequencies of IgM antibodies against cardiolipin (P = 0.05) and IgG-antibodies against cardiolipin and phosphatidylserine (P = 0.011). Drug users had higher IgM antibodies against phospholipids than patients from other risk groups (P = 0.02). A history of thromboembolic events was not accompanied by higher levels of anti-phospholipid antibodies (P > 0.2). No correlation between anti-phospholipid antibodies and CD5+ B cells was detected. Percentage part of CD5+ B lymphocytes was elevated in all patients and absolute CD4+ T lymphocyte counts and HIV p24 antigen were inversely correlated. In advanced disease a significant reduction of anti-phospholipid antibodies was contrasted with persistent elevation of CD5+ B lymphocytes. These observations may reflect immunological dysfunction involving apoptosis and endothelial damage rather than polyclonal B cell hyperstimulation. A possible explanation would be that in HIV infection an increased rate of spontaneous apoptosis in peripheral blood lymphocytes is accompanied by functional and structural changes of mitochondria. Therefore, structurally altered mitochondrial phospholipids could serve as antigen to induce specific humoral immune responses.     

FTY720, a novel immunosuppressant, induces sequestration of circulating mature lymphocytes by acceleration of lymphocyte homing in rats, III. Increase in frequency of CD62L-positive T cells in Peyer's patches by FTY720-induced lymphocyte homing.

FTY720, a novel immunosuppressant, sequesters circulating mature lymphocytes, especially T cells, within lymph nodes and Peyer's patches by accelerating lymphocyte homing, and thereby causes lymphocyte depletion in the blood. The FTY720-induced acceleration of lymphocyte homing appears to be mediated by lymphocyte homing receptors including CD62L, CD49d/beta7, and CD11a/CD18. In this study, expressions of CD62L, CD49d and CD11a on T cells in the peripheral blood, lymph nodes and Peyer's patches were analysed by flow cytometry in rats given FTY720 (1 mg/kg) orally. FTY720 markedly decreased the number of peripheral blood T cells, while not affecting CD62L, CD49d and CD11a expressions at 1-3 hr after administration. In contrast, both the frequency of CD62L-positive T cells and intensity of CD62L expression on T cells were increased in Peyer's patches but not lymph nodes at 3 hr after administration of FTY720. CD49d and CD11a expressions on T cells were unaffected by FTY720 in both Peyer's patches and lymph nodes at the same point in time. On the other hand, analysis of lymphocyte homing with calcein-labelled lymphocytes and anti-CD62L monoclonal antibody (mAb) confirmed that FTY720 predominantly increased CD62L-dependent lymphocyte homing to Peyer's patches. These findings indicate that FTY720 increases the frequency of CD62L-positive T cells by accelerating CD62L-predominant homing in Peyer's patches.     

Protective effect of DNA immunization against mycobacterial infection is associated with the early emergence of interferon-gamma (IFN-gamma)-secreting lymphocytes

The development of more effective anti-tuberculosis (TB) vaccines would contribute to the global control of TB. Understanding the activated/memory T cell response to mycobacterial infection and identifying immunological correlates of protective immunity will facilitate the design and assessment of new candidate vaccines. Therefore, we investigated the kinetics of the CD4+ T cell response and IFN-gamma production in an intravenous challenge model of Mycobacterium bovis bacille Calmette-Guérin (BCG) before and after DNA immunization. Activated/memory CD4+ T cells, defined as CD44hiCD45RBlo, expanded following infection, peaking at 3-4 weeks, and decreased as the bacterial load fell. Activated/memory CD4+ T cells were the major source of IFN-gamma and the level of antigen-specific IFN-gamma-secreting lymphocytes, detected by ELISPOT, paralleled the changes in bacterial load. To examine the effects of a DNA vaccine, we immunized mice with a plasmid expressing the mycobacterial secreted antigen 85B (Ag85B). This led to a significant reduction in mycobacteria in the liver, spleen and lung. This protective effect was associated with the rapid emergence of antigen-specific IFN-gamma-secreting lymphocytes which were detected earlier, at day 4, and at higher levels than in infected animals immunized with a control vector. This early and increased response of IFN-gamma-secreting T cells may serve as a correlate of protective immunity for anti-TB vaccines.     

Exogenous Melatonin Up-Regulates Expression of CD62L by Lymphocytes in Aged Mice under Inflammatory and Non-Inflammatory Conditions

It is well documented that age-related impaired functioning of immunocompetent cells is associated with an increase in the rates of chronic inflammatory diseases. Recently, an ability of melatonin to modulate inflammatory processes by regulating leucocyte recruitment has been demonstrated. However, to date, no studies have attempted to determine the impact of melatonin on the expression of CD62L by lymphocytes. CD62L, also known as L-selectin, is required for the entry of lymphocytes into secondary lymphoid organs, sites of tumor growth and chronic inflammation through high endothelial venules. Here, we investigated the effect of melatonin at physiological concentrations on the expression of CD62L by T and NK cells in vivo and in vitro. We demonstrated that NK and CD3⁺ T cells obtained from the spleen of aged mice were characterized by decreased expression of CD62L compared to young mice. Melatonin administration up-regulated the levels of surface CD62L on NK and T cell populations in aged mice under non-inflammatory conditions and on CD8⁺ T cells in aged mice with chronic inflammation. Pre-incubation with melatonin prevented the reduction in CD62L expression by CD8⁺ T cells induced by the co-cultivation of peripheral blood mononuclear cells with human pancreatic adenocarcinoma cell line (MiaPaCa-2). The obtained results suggest that melatonin can modulate lymphocyte homing into lymph nodes and sites of chronic inflammation and, therefore, can stimulate immune responses in chronic inflammatory conditions associated with aging.     

Increased plasma levels of matrix metalloproteinase-9 are associated with the severity of chronic urticaria

BACKGROUND: Matrix metalloproteinase (MMP)-9 is produced by many inflammatory cells such as macrophages, neutrophils, mast cells, eosinophils and T lymphocytes. Activated T cells are capable, through cell-cell contact, of inducing MMP-9 expression in human mast cells. OBJECTIVE: To investigate the activation status of peripheral CD4+ T cells and the level of MMP-9 in the plasma of patients with chronic urticaria (CU), and whether MMP-9 levels are in association with CU severity. METHODS: Study subjects included 29 patients with CU and 30 healthy control subjects. At the time of assessment, patients were divided into subgroups according to urticarial severity. Plasma levels of total MMP-9 (free pro-MMP-9 and free MMP-9) were determined by ELISA. CD4+ lymphocytes were positively selected with magnetic microbeads. After 48 h of activation, CD4+ T cells were assayed for both nuclear factor-kappa B (NF-kappa B) expression and proliferation. RESULTS: Plasma levels of MMP-9 were found to be significantly higher in 29 CU patients compared with 18 healthy controls (186 +/- 174 vs. 31 +/- 21 ng/mL, P<0.0001). We also found a significant correlation between MMP-9 levels and urticarial severity (r = 0.92, P<0.001). In addition, CD4+ T cells from CU patients expressed higher levels of NF-kappa B than CD4+ T cells from healthy controls (82 +/- 30 vs. 69 +/- 20 optical density, P = 0.007). Finally, as compared with seven healthy individuals, DNA synthesis in CD4+ T cells from seven CU patients was found to be significantly elevated (1000 +/- 240 vs. 751 +/- 166 counts per minute, P = 0.01). CONCLUSION: Increased levels of MMP-9 are found in CU patients, and particularly among those with severe disease. We also demonstrated that CD4+ T cells from such patients are highly activated.     

Expression of chemokine receptors CXCR4, CXCR5 and CCR7 on B and T lymphocytes from patients with primary antibody deficiency

The interaction of chemokines and their receptors directs lymphocyte migration, and is involved in the distribution and organization of lymphocytes within lymphoid tissues. We reasoned that abnormal chemokine receptor expression might give rise to defects of lymphocyte migration into and within lymphoid tissues, and consequently be associated with defective antibody production in primary antibody deficiencies. In this study, we have investigated the expression of chemokine receptors CXCR4, CXCR5 and CCR7 on lymphocyte subpopulations (naive and memory B cells; CD4⁺ and CD8⁺ T cells) in a cohort of patients with primary antibody deficiency (n = 23), and compared these with a group of healthy controls (n = 19). We show that there were significant differences in both the proportions of lymphocytes expressing, and the levels of expression of, specific chemokine receptors on individual lymphocyte subpopulations between patients and controls. Furthermore, these changes appeared more pronounced in patients with more severe antibody deficiency. These data support the hypothesis that abnormal lymphocyte trafficking may be involved in the pathogenesis of primary antibody deficiencies.     

Expression of mucosa-related integrin alphaEbeta7 on alveolar T cells in interstitial lung diseases.

The expression of alphaEbeta7 integrin has been related to the selective retention of lymphocytes in mucosal tissues of gut, urogenital tract and lung. To identify potential disease-associated alphaEbeta7 expression patterns on cells accounting for lymphocytic alveolitis in interstitial lung disease (ILD), alphaE expression on CD4+ and CD8+ T cell subsets was evaluated by dual-colour flow cytometry in peripheral blood and bronchoalveolar lavage fluid (BALF) of patients with idiopathic pulmonary fibrosis (IPF; n = 18), hypersensitivity pneumonitis (HP; n = 20) and sarcoidosis (n = 44) in comparison with healthy controls (n = 15). In both healthy individuals and all patient groups the proportion of alphaE-bearing T cells in peripheral blood was < 2%, whereas the vast majority of alveolar CD8+ T cells consistently co-expressed alphaE. Absolute alveolar CD8+alphaE+ cell numbers/ml were up to 30-fold increased in HP patients. Proportions of alphaE-bearing CD4+ cells in BALF were significantly elevated in IPF (74.0 +/- 2.7%) and HP (70.0 +/- 2.4%) compared with normals (30.0 +/- 1.8%) (mean +/- s.e.m.; P < 0.01). In sarcoidosis, the alphaE expression on BALF CD4+ cells displayed subgroup dependency: proportions significantly lower than normal were noted in chest radiographic stage I (14.3 +/- 1.5%), but increased proportions in stages II (50.0 +/- 3.8%) and III (64.0 +/- 4.8%). Correlations between common markers of T cell activation or BALF transforming growth factor-beta (TGF-beta ) bioactivity and alphaE expression were not noted. We conclude that the vast majority of alveolar CD8+ T cells consistently express alphaEbeta7 and that distinct patterns of alphaEbeta7 expression on alveolar CD4+ lymphocytes in sarcoidosis are related to the diverse manifestations of the sarcoid inflammatory process in the lung.     

Effector T lymphocytes in well-nourished and malnourished infected children

The mechanisms involved in impaired immunity in malnourished children are not well understood. CD4(+) CD62L(-) and CD8(+) CD28(-) do not express the naive cell markers CD62L and CD28, suggesting that they function as effector T cells. Using a flow cytometry-based analysis we examined the proportions of CD4(+) CD62L(-) and CD8(+) CD28(-) T cell subsets in well-nourished infected (WNI) and malnourished infected (MNI) children. Here we report that WNI children had a higher percentage of CD4(+) CD62L(-) (11.1 +/- 1.0) and CD8(+) D28(-) (40.2 +/- 5.0) T cell subsets than healthy (6.5 +/- 1.0 and 23.9 +/- 4.8) and MNI children (7.4 +/- 1.1 and 23.1 +/- 6.2, respectively) (P < 0.5). Data suggest that WNI children respond efficiently against pathogenic microbes. In contrast, relatively low numbers of circulating of CD4(+) CD62L(-) and CD8(+) CD28(-) T cells in MNI children may represent an ineffective response to infection. Levels of effector T cells in children with gastrointestinal infections versus those suffering from respiratory infections were also significantly different within the WNI group. While WNI children with gastrointestinal infections had higher absolute and relative values of CD8(+), and CD8(+) CD28(-) T subsets, by those with respiratory infections had higher values of CD4(+) lymphocytes. However, due to the small number of subjects examined, our results in WNI children should be interpreted with caution and confirmed using a larger sample size. Our data suggest that altered expression of CD62L and CD28 receptors may contribute to impaired T cell function observed in MNI children.     

Lack of age-associated LFA-1 up-regulation and impaired ICAM-1 binding in lymphocytes from patients with Down syndrome.

To investigate the role of LFA-1 in the immune defects in DS patients, we analysed lymphocytes from DS patients in LFA-1 expression and LFA-1 mediated cell adhesion. DS patients less than 2 years of age expressed a higher level of LFA-1 when compared with age-matched controls. The difference in LFA-1 expression was much less significant in older DS patients when compared with age-matched children. Although older children (2-15-year-old groups) without DS tend to increase their expression of lymphocyte LFA-1 when compared with younger normal children (0-2 years old), DS patients showed no age-associated increase in lymphocyte LFA-1 expression. Two-colour analysis with CD4/CD8 and LFA-1 in patients and controls showed that proportions of CD4 + lymphocytes were comparable in DS patients and controls, while the proportion of CD8 + lymphocytes was higher in older DS patients. Expression levels of LFA-1 on both CD4 + and CD8 + lymphocytes in younger DS patients were higher when compared with age-matched controls and close to the expression levels in the older DS group. Proportions of memory lymphocytes expressing the CD45RO isoform were higher in both younger and older DS patients when compared with age-matched control groups. Noticeably, the LFA-1 expression levels on CD45RO lymphocytes from younger DS patients were higher than the levels of the controls and declined in the older DS group. We tested lymphocytes (EBV transformed B cells, resting and anti-CD3 stimulated T cells) for cellular adhesion to recombinant ICAM-1 and found that lymphocytes from DS patients were less adhesive, even though their beta2 integrin expression was comparable with that of normal controls. These results suggest that more generalized pathological processes, such as early senescence of the immune system or ineffective lymphocyte activation, and subsequent integrin dysfunction may underlie the immune defects in DS patients.     

Intestinal nodular lymphoid hyperplasia in patients with common variable immunodeficiency: Local accumulation of B and CD8(+) lymphocytes

Common variable immunodeficiency (CVI) with hypogammaglobulinemia is often complicated by nodularlymphoid hyperplasia of the intestine. In this study the lymphoid constituents of intestinal nodular hyperplasia of five CVI patients were characterized with monoclonal antibodies. Few CD4(+) but abundant CD8(+) T lymphocytes were found around the follicles. The follicles were populated mainly by B cells expressing surface IgM. A few cells in the lamina propria expressed Leu7. No intracytoplasmic immunoglobulin-containing plasma cells were seen. Peyer's patches in gut biopsies from controls were also composed of follicles with B lymphocytes. A ring of T lymphocytes surrounded the follicles. CD4(+) helper cells largely outnumbered CD8(+) cells in this ring. Moreover, plasma cells were present in the lamina propria and the mixed cell zone covering the follicles. In peripheral blood of the patients, B cells were present in normal proportions but they could not be induced to produce IgGin vitro by T cell-dependent (pokeweed mitogen) or T cell-independent (Staphylococcus aureus Cowan I) mitogens. In two of the patients, IgM production could be inducedin vitro. Peripheral blood T cells were predominantly CD8(+) in three of the five patients, and in these same patients an increase in suppressor-cell activity of peripheral blood T cells on immunoglobulin production was observed. The data demonstrate a block in B-cell differentiation in the gut and in peripheral blood. Whether the local increase in CD8(+) cells in the nodular lymphoid hyperplasia is a primary event or is secondary to chronic immune stimulation and whether it contributes to local inhibition of B-cell differentiation remain to be investigated.Presented in part at the 87th annual meeting of the American Gastroenterological Association and Digestive Disease Week, May 17–23, 1986, San Francisco, California.     

Circulating CD4+ and CD8+ T cells are activated in inflammatory bowel disease and are associated with plasma markers of inflammation

Inflammatory bowel disease (IBD) is characterized by damage to the gut mucosa and systemic inflammation. We sought to evaluate the role of chronic inflammation on circulating T‐cell activation in human subjects with Crohn's disease and ulcerative colitis. We studied 54 patients with IBD and 28 healthy controls. T‐cell activation and cycling were assessed in whole blood samples by flow cytometry. Levels of lipopolysaccharide (LPS) were measured in serum by Limulus amoebocyte lysate assay, and plasma levels of inflammatory markers and LPS‐binding proteins were measured by ELISA. The proportions of circulating CD4⁺ and CD8⁺ T lymphocytes in cycle (Ki67⁺) are increased in patients with IBD compared with these proportions in controls. CD8⁺ T cells from patients with IBD are also enriched for cells that expressed CD38 and HLA‐DR, and proportions of these cells are related to plasma levels of interleukin‐6 and C‐reactive protein in these patients. Intracellular interleukin‐2 and interferon‐γ levels were elevated in resting and polyclonally activated CD4⁺ and CD8⁺ T cells in patients with IBD when compared with levels from healthy controls. Surprisingly, we did not find increased levels of LPS in the serum of patients with IBD. We did, however, find a signature of recent microbial translocation, as levels of LPS‐binding protein are increased in the plasma of patients with IBD compared with plasma levels in healthy controls; LPS‐binding protein levels are also directly related to proportions of CD38 HLA‐DR‐expressing CD4⁺ and CD8⁺ T cells. Local damage to the gastrointestinal tract in IBD may result in systemic inflammation and T‐cell activation.     

Soluble and cellular markers of immune activation in patients with systemic sclerosis

The peripheral blood lymphocyte pattern, the lymphocyte responses in vitro, as well as the soluble markers of immune activation were studied in 24 patients with systemic sclerosis (SSc patients). The proportions of total T cells (CD3), their CD4 subset, as well as B lymphocytes were within the normal range. The relative proportion of CD8 lymphocytes, however, was significantly reduced. Patients with SSc had a slightly lower percentage of CD4/4B4+ cells, whereas their proportion of CD4/2H4+ cells was elevated as compared to healthy controls. The proportion of lymphocytes expressing the interleukin-2 receptor (IL-2R) was significantly higher in SSc patients. The proliferative responses of peripheral blood mononuclear cells to PHA stimulation were reduced in the patient group, while expression of IL-2R on lymphocytes after such in vitro stimulation was comparable to that of controls. Expression of IL-2R on patient but not control lymphocytes was increased after in vitro exposure to laminin. Such exposure failed to induce IL-2 production or cell proliferative responses. Soluble plasma IL-2R level (sIL-2R) and soluble CD8 (sCD8) molecule levels in SSc patients were significantly elevated. These results indicate the presence of an ongoing lymphocyte activation in this disease process.