Treatment of severe autoimmune blistering skin diseases with combination of protein A immunoadsorption and rituximab: a protocol without initial high dose or pulse steroid medication.

BACKGROUND: Skin blistering diseases due to autoantibodies are typically treated with high dose systemic corticosteroids and other conventional immunosuppressants. However, in severe cases, this treatment may not be sufficient to achieve disease control or contraindicated because of comorbidity. METHODS: We describe 15 patients (pts.) with such diseases: 6 pts. with pemphigus vulgaris, 3 pts. with bullous pemphigoid, 3 pts. with mucous membrane pemphigoid (MMP), one being anti-laminin-332-MMP (AL332-MMP), 2 pts. with pemphigus foliaceus and 1 pt. with epidermolysis bullosa acquisita (EBA). Patients were treated with a combination of protein A immunoadsorption (PAIA, 3-21 treatments) and rituximab (3-6 treatments) in addition to low dose conventional immunosuppression. RESULTS: All patients showed rapid clinical improvement starting within the first 4 weeks and decline of circulating autoantibody levels. Complete/partial remission was 88%/12% in pemphigus and 71%/29% in subepidermal blistering diseases. Overall relapse rate was 13% with an average follow-up of 22 months. In the AL332-MMP pt. the PAIA/rituximab treatment was stopped because of an oesophagus cancer considered as the paraneoplastic cause of the skin disease. CONCLUSION: Combined treatment with PAIA and rituximab showed rapid and long-lasting response, thereby allowing substantial reduction of dosage of concomitant immunosuppressive medication. We hereby confirm data from other investigators that PAIA/rituximab treatment is a promising therapeutical modality for pemphigus, pemphigoids and EBA, characterized by a favourable ratio of beneficial efficacy and minimized long-term adverse effects.

The digital MIQE guidelines: Minimum Information for Publication of Quantitative Digital PCR Experiments.

There is growing interest in digital PCR (dPCR) because technological progress makes it a practical and increasingly affordable technology. dPCR allows the precise quantification of nucleic acids, facilitating the measurement of small percentage differences and quantification of rare variants. dPCR may also be more reproducible and less susceptible to inhibition than quantitative real-time PCR (qPCR). Consequently, dPCR has the potential to have a substantial impact on research as well as diagnostic applications. However, as with qPCR, the ability to perform robust meaningful experiments requires careful design and adequate controls. To assist independent evaluation of experimental data, comprehensive disclosure of all relevant experimental details is required. To facilitate this process we present the Minimum Information for Publication of Quantitative Digital PCR Experiments guidelines. This report addresses known requirements for dPCR that have already been identified during this early stage of its development and commercial implementation. Adoption of these guidelines by the scientific community will help to standardize experimental protocols, maximize efficient utilization of resources, and enhance the impact of this promising new technology.

Progressive lipo-lymphedema associated with increased activity of dermal fibroblasts in monoclonal gammopathy of undetermined significance: is there a causal relationship?

The pathophysiology of skin diseases associated with monoclonal gammopathies is generally unknown. Our aim was to investigate whether a monoclonal gammopathy could be a causal factor in progressive lymphedema. We describe a 75 year old patient with a rapidly progressive lipo-lymphedema and a monoclonal gammopathy of unknown significance (MGUS) suspected as a key etiological factor. Dermal fibroblasts were cultured from lesional lower leg skin and non-lesional abdominal skin and compared to healthy control fibroblasts. We found 10-fold elevated basic fibroblast growth factor 2 (FGF-2) in the patient's serum and significantly increased basal FGF-2 production of lesional and non-lesional fibroblasts compared to healthy controls. Upon restimulation with patient or healthy control serum, lesional fibroblasts showed significantly increased proliferation rates and FGF-2 production in vitro. Non-lesional abdominal fibroblasts showed an intermediate phenotype between lesional and control fibroblasts. Our findings provide the first evidence that lesional dermal fibroblasts from lipo-lymphedema with plasma cell infiltration show increased proliferation and FGF-2 production and that both local tissue factors and altered FGF-2 serum levels associated with monoclonal gammopathies might contribute to this phenotype. Thus we propose a possible pathophysiologic link between the gammopathy-associated factors and the generation of lymphedema with initial fibrogenesis aggravating pre-existing lipedema.

Identification of GP2, the major zymogen granule membrane glycoprotein, as the autoantigen of pancreatic antibodies in Crohn's disease.

BACKGROUND AND AIMS: The aetiopathogenesis of Crohn's disease, an inflammatory bowel disease (IBD), is not yet fully understood. Autoimmune mechanisms are thought to play a role in the development of Crohn's disease, but the target antigens and the underlying pathways have not been sufficiently identified. METHODS: Based on data from immunoblotting and matrix-assisted laser desorption ionisation time-of-flight (MALDI-TOF) mass spectrometry, the major antigenic target of pancreatic autoantibodies (PABs), which are specific for Crohn's disease, was identified. Specificity of autoantibody reactivity was confirmed by enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence (IIF) using purified rat and human recombinant GP2 synthesised in transiently transfected mammalian HEK 293 cells. Real-time polymerase chain reaction (rt-PCR) and IIF were used to detect mRNA and antigen localisation in human colon biopsies. RESULTS: The major zymogen granule membrane glycoprotein 2 (GP2) was identified as the autoantigen of PABs in Crohn's disease. PAB-positive sera from patients with Crohn's disease (n = 42) displayed significantly higher IgG reactivity to rat GP2 in ELISA than either PAB-negative sera (n = 31), or sera from patients with ulcerative colitis (n = 49), or sera from blood donors (n = 69) (p<0.0001, respectively). Twenty-eight (66%) and 18 (43%) of 42 PAB-positive sera demonstrated IgG and IgA reactivity to human recombinant GP2 in IIF, respectively. Patients with PAB-negative Crohn's disease (n = 31) were not reactive. GP2 mRNA transcription was significantly higher in colon biopsies from patients with Crohn's disease (n = 4) compared to patients with ulcerative colitis (n = 4) (p = 0.0286). Immunochemical staining confirmed GP2 expression in human colon biopsies from patients with Crohn's disease. CONCLUSION: Anti-GP2 autoantibodies constitute novel Crohn's disease-specific markers, the quantification of which could significantly improve the serological diagnosis of IBD. The expression of GP2 in human enterocytes suggests an important role for anti-GP2 response in the pathogenesis of Crohn's disease.

Regulation of in vitro and in vivo immune functions by the cytosolic adaptor protein SKAP-HOM.

SKAP-HOM is a cytosolic adaptor protein representing a specific substrate for the Src family protein tyrosine kinase Fyn. Previously, several groups have provided experimental evidence that SKAP-HOM (most likely in cooperation with the cytosolic adaptor protein ADAP) is involved in regulating leukocyte adhesion. To further assess the physiological role of SKAP-HOM, we investigated the immune system of SKAP-HOM-deficient mice. Our data show that T-cell responses towards a variety of stimuli are unaffected in the absence of SKAP-HOM. Similarly, B-cell receptor (BCR)-mediated total tyrosine phosphorylation and phosphorylation of Erk, p38, and JNK, as well as immunoreceptor-mediated Ca(2+) responses, are normal in SKAP-HOM(-/-) animals. However, despite apparently normal membrane-proximal signaling events, BCR-mediated proliferation is strongly attenuated in the absence of SKAP-HOM(-/-). In addition, adhesion of activated B cells to fibronectin (a ligand for beta1 integrins) as well as to ICAM-1 (a ligand for beta2 integrins) is strongly reduced. In vivo, the loss of SKAP-HOM results in a less severe clinical course of experimental autoimmune encephalomyelitis following immunization of mice with the encephalitogenic peptide of MOG (myelin oligodendrocyte glycoprotein). This is accompanied by strongly reduced serum levels of MOG-specific antibodies and lower MOG-specific T-cell responses. In summary, our data suggest that SKAP-HOM is required for proper activation of the immune system, likely by regulating the cross-talk between immunoreceptors and integrins.

Clinical symptom tool that raises the index of suspicion for eosinophilic oesophagitis in adults and drives earlier biopsy for definitive diagnosis.

BACKGROUND: Eosinophilic oesophagitis (EoE) and gastro-oesophageal reflux disease (GERD) present with overlapping symptomatology and it is challenging to distinguish EoE from GERD clinically before endoscopy. AIM: To investigate the prognostic value of a set of clinical symptoms and laboratory values in patients with EoE and GERD. METHODS: In this prospective, single-centre, observational study, we compared clinical and laboratory data from 202 patients with EoE or GERD (10 relevant characteristics). Those characteristics showing potential significance in a univariate analysis were then included in a multivariate analysis. RESULTS: The set of 10 characteristics (10-marker set) was able to distinguish between EoE and GERD with good reliability (correct assignment, i.e. agreement with subsequent EGD, of 94.4%). Reduction of the set to the six statistically and clinically most relevant markers continued to give good reliability (88.9%), and further stepwise reduction led to four-marker sets comprising history of atopy, history of food impaction, proton pump inhibitor refractory symptoms and either immunoglobulin E or peripheral eosinophilia, with correct assignment rates of 91.3% and 85.1% respectively. CONCLUSIONS: We have developed a simple and easily applicable clinical/laboratory marker set that helps to distinguish EoE from GERD earlier in the treatment course, thus guiding the endoscopist to perform biopsies from the oesophagus to ensure the diagnosis. The application of the scoring system is expected to diagnose EoE earlier and avoiding delay of adequate treatment.

Autoimmunity in Crohn's Disease-A Putative Stratification Factor of the Clinical Phenotype.

Inflammation in inflammatory bowel diseases (IBD) has been linked to a loss of tolerance to self-antigens suggesting the existence of autoantibodies in specific disease phenotypes. However, the lack of clearly defined autoantigenic targets has slowed down research. Genome-wide association studies have identified an impressive number of immune-related susceptibility loci for IBD with no clearly discernible pattern among them. Growing evidence supports the hypothesis that innate immune responses to a low-diversity and impaired gut microbiota may be of key importance in initiating and perpetuating chronic inflammation in IBD. Increasing evidence suggests that reduced microbial diversity and microbial-mucosal epithelium interaction (including adhesion and clearance) are critically involved in IBD pathogenesis. Along these lines the discovery of autoantigenic targets in Crohn's disease (CD) has refocused research in IBD on the possible role of autoimmune responses. The identification of the major zymogen granule membrane glycoprotein 2 (GP2) as an autoantigen in CD patients and its proposed role in the sensing of the microbiota lends credence to this trend. Loss of tolerance to GP2 occurs in up to 40% of patients with CD. Corresponding autoantibodies appear to be associated with distinct disease courses (types or phenotypes) in CD. Here, we critically review autoantibodies in CD for their impact on clinical practice and future IBD research. The immunomodulatory role of GP2 in innate and adaptive intestinal immunity is also discussed.

Phorbol ester-induced shedding of intercellular adhesion molecule-1 (ICAM-1) on erythroleukemic K 562 cells.

The effect of phorbol 12-myristate 13-acetate (PMA) on the expression and shedding of intercellular adhesion molecule-1 (ICAM-1) was investigated on the hematopoietic cell lines K 562 and U 937 using flow cytometry, fluorescence microscopy and ELISA technique. At low concentration of 1 nM, PMA stimulated the expression of ICAM-1 on the cell surface about 4-fold within 24 h, whereas a short-term treatment with 100 nM PMA led to the shedding of 35% of ICAM-1 from the surface of K 562 cells. The release of surface ICAM-1 was found on single cells by fluorescence microscopy to be a uniform process proceeding within 15 min. The shedding of ICAM-1 correlated with elevated levels of sICAM-1 in the supernatants of cultured cells. Also on K 562 cells stimulated by TNF-alpha, a PMA-induced release of ICAM-1 was observed in addition to the known spontaneous shedding. In contrast to the results with K 562 cells, no PMA-induced shedding of ICAM-1 was found on U 937 cells. This indicates a cell-specific process for K 562 cells. The PMA-mediated release of ICAM-1 from K 562 cells suggests that the shedding process does not only occur in parallel to the surface expression of ICAM-1, but may be controlled by particular mechanisms of down-regulation.

Autoimmune gastritis in autoimmune thyroid disease.

BACKGROUND: Autoimmune gastritis leads to oxyntic gastric atrophy, a condition at increased risk for gastric cancer. Autoimmune gastritis in conjunction with autoimmune thyroid disease has been reported previously. AIM: In a case-control study in patients with autoimmune thyroid disease to evaluate the usefulness of serum pepsinogens for the identification of oxyntic gastric atrophy, and to determine the relationship of Helicobacter pylori with oxyntic gastric atrophy. METHODS: Patients with autoimmune thyroid disease (cases) and goitre (controls) were prospectively enrolled in the study. Pepsinogen (PG) I levels ≤25 µg/mL and PG I/II ratio ≤3 were indicative for oxyntic gastric atrophy. Antibodies against H. pylori, CagA and parietal cells were also determined. Esophagogastroduodenoscopy with biopsies was offered to patients with serological oxyntic gastric atrophy. RESULTS: In total, 34 autoimmune thyroid disease patients and 30 controls were enrolled. Serological oxyntic gastric atrophy was present only in autoimmune thyroid disease patients (8/34, 23.5%, OR 8.3, 95% CI = 1.9-36.2). In all eight patients oxyntic gastric atrophy was confirmed by histology. OLGA stage I, II, III and IV was described in 0%, 33%, 50% and 17% of the cases, respectively. About, 89% and 11% of oxyntic gastric atrophy patients were seropositive for antibodies against parietal cells or H. pylori infection, respectively. Gastric atrophy involved the angulus/antrum in 50% of patients with autoimmune gastritis. CONCLUSIONS: The seroprevalence of oxyntic gastric atrophy is high in patients with autoimmune thyroid disease, and testing of serum pepsinogens should be included in the clinical assessment of these patients. H. pylori infection is unlikely to be a principal factor in the pathogenesis of oxyntic gastric atrophy in patients with autoimmune thyroid disease. In autoimmune gastritis, gastric atrophy can spread from the oxyntic towards the antral mucosa.

Evidence for a crucial role of neutrophil-derived serine proteases in the inactivation of interleukin-6 at sites of inflammation.

The bioactivity of interleukin-6 (IL-6) was found to be dramatically reduced in fluids from sites of inflammation. Here, we provide evidence that the neutrophil-derived serine proteases elastase, proteinase 3 and cathepsin G are mainly involved in its degradation and subsequent inactivation. The initially hydrolyzed peptide bonds were detected to be Val(11)-Ala(12) and Leu(19)-Thr(20) (elastase), Phe(78)-Asn(79) (cathepsin G) and Ala(145)-Ser(146) (proteinase 3). The soluble IL-6 receptor elicits a protective effect against the IL-6 inactivation by cathepsin G only. The inactivation of IL-6 by neutrophil-derived serine proteases might act as a feedback mechanism terminating the IL-6-induced activation of neutrophils.

Amino-terminal truncation of procalcitonin, a marker for systemic bacterial infections, by dipeptidyl peptidase IV (DP IV).

Increased concentrations of procalcitonin (PCT) are found in the plasma of patients with thermal injury and in patients with sepsis and severe infection, making this molecule important as a diagnostic and prognostic marker in these diseases. Interestingly, only the truncated form of PCT, PCT(3-116), is present in the plasma of these patients. The enzyme responsible for this truncation is unknown as yet. Here, using capillary zone electrophoresis, mass spectrometry and Edman sequence analysis, we demonstrate that dipeptidyl peptidase IV (DP IV, EC 3.4.14.5) is capable of catalyzing the hydrolysis of PCT(1-116), releasing the N-terminal dipeptide Ala-Pro. We hypothesize that PCT(3-116) is the result of the hydrolysis of PCT(1-116) by soluble DP IV of the blood plasma or by DP IV expressed on the surface of cells.

The N-terminal X-X-Pro sequence of the HIV-1 Tat protein is important for the inhibition of dipeptidyl peptidase IV (DP IV/CD26) and the suppression of mitogen-induced proliferation of human T cells.

Recent data in the literature suggest that the HIV-1 Tat(1-86) protein exhibits immunosuppressive effects. Moreover, Tat was found to interact with dipeptidyl peptidase IV (DP IV), which is identical to the T cell activation marker CD26. Here we show that the N-terminal amino acid sequence of Tat is essential for the inhibition of DP IV-catalyzed IL-2(1-12) degradation. N-terminal modification of Tat with rhodamine prevented inhibition of enzymatic activity of DP IV as well as suppression of DNA synthesis of mitogen-stimulated human T cells. Moreover, natural peptides containing the X-X-Pro N-terminal motif of Tat also inhibited DP IV activity. These data suggest the existence of endogenous immunomodulatory oligopeptides which influence immune cell proliferation and differentiation via DP IV as does HIV-1 Tat.

Dipeptidyl peptidase IV (DP IV, CD26) is involved in regulation of DNA synthesis in human keratinocytes.

Various studies have shown that the membrane ectoenzyme dipeptidyl peptidase IV (DP IV, CD26), expressed on T, NK, and B cells in the human immune system, is involved in the regulation of DNA synthesis and cytokine production. Here, we clearly demonstrate that this enzyme is highly expressed also on human epidermal foreskin and split-skin keratinocytes and that the specific DP IV inhibitors Lys[Z(NO2)]-thiazolidide, Lys[Z(NO2)]-pyrrolidide inhibit the enzymatic activity as well as the DNA synthesis of these cells. These data demonstrate that CD26 plays a role also in regulation of DNA synthesis of epidermal keratinocytes and that the enzymatic activity is required for mediating these effects.

Transforming growth factor beta 1 inhibits interleukin-10 mRNA expression and production in pokeweed mitogen-stimulated peripheral blood mononuclear cells and T cells.

The multifunctional cytokine transforming growth factor-beta 1 (TGF-beta 1) is known to inhibit the proliferation of lymphocytes. Whether this effect is a result of a direct action of TGF-beta 1 or an involvement of other "immunoinhibitory" cytokines is not yet clear. Here we have analyzed the effects of TGF-beta 1 on IL-10 and IL-1RA production in pokeweed mitogen-stimulated peripheral blood mononuclear cells (PBMC) and purified T lymphocytes. We show in these systems that TGF-beta 1 at a concentration of 10 ng/ml significantly suppresses both IL-10 mRNA expression and IL-10 production. IL-2 and IL-6 were capable of abolishing the effect of TGF-beta 1 on DNA synthesis and production of IL-10 by T lymphocytes in an additive manner. However, TGF-beta 1 did not influence IL-1RA production in PWM-stimulated PBMC. The present data show that the inhibitory effect of TGF-beta 1 on mitogen-activated immune cells is not the consequence of induction of the inhibitory cytokines IL-10 or IL-1RA but rather an inhibitory action on the production of IL-2 and/or IL-6.

Selective proteolytic cleavage of IL-2 receptor and IL-6 receptor ligand binding chains by neutrophil-derived serine proteases at foci of inflammation.

Traumatic brain injuries induce a strong, locally restricted inflammatory response. Here we demonstrate that activated neutrophils infiltrate the site of tissue destruction and release large amounts of enzymatically active elastase, cathepsin G, and proteinase 3. High intracerebral protease concentrations were found to be accompanied by a reduced inhibitory potential at foci of inflammation. In 39 neurotrauma patients, a temporal correlation between the protease release from neutrophils and the solubilization of interleukin-2 (IL-2) receptor and IL-6 receptor ectodomains at sites of tissue destruction was observed, suggesting that neutrophil-derived proteases may play a crucial role in the cytokine receptor shedding at foci of inflammation. Under in vitro conditions, the cleavage of membrane-bound IL-2Ralpha was found to be predominantly catalyzed by elastase and, to a lesser extent, by proteinase 3. Cathepsin G was found to be incapable of solubilizing this receptor. In contrast, the cleavage of the IL-6R 80 kDa chain was catalyzed by cathepsin G but not by elastase or proteinase 3. The receptor fragments released by the action of these enzymes were found to retain their ligand-binding capacity. These results strongly suggest a pathophysiologic role of neutrophil-derived serine proteases, particularly in regulation of the expression of functional IL-2 and IL-6 receptors at foci of inflammation.

Renal cell carcinomas produce IL-6, IL-10, IL-11, and TGF-beta 1 in primary cultures and modulate T lymphocyte blast transformation.

We investigated the immunomodulatory capacity of primary cultures of renal cell carcinomas (RCC) by assessing production of cytokines and modulation of mitogen-induced T lymphocyte blast transformation. The results clearly show that immunomodulatory capacity is a common feature of RCC and that in vitro these tumors can produce interleukin-10 (IL-10) up to 20 ng/ml, IL-6 up to 35 micrograms/ml (> 250 kU/ml in the B9 system), IL-11 up to 15 micrograms/ml, and transforming growth factor-beta 1 (TGF-beta 1) up to 22 ng/ml. Furthermore, these tumors have the capacity to modulate T cell blast transformation over two orders of magnitude in each direction. The correlations of the immunologic properties of tumor cell cultures with the conventional classification of tumors (histology, cytology, staging, grading, presence of metastases, and secondary tumors) are analyzed. The significance of these findings for modulation of local immunity by RCC as well as for patient outcome is discussed.

Increased release of transforming growth factor (TGF)-beta1, TGF-beta2, and chemoattractant mediators in pneumonia.

Transforming growth factor-beta (TGF-beta), interleukin-8 (IL-8), and leukotrienes are potent neutrophil chemoattractants that are released in several lung diseases. There is limited information about the release of TGF-beta in bronchoalveolar lavage fluid (BALF) of patients with pneumonia. Furthermore, it is not clear if TGF-beta is differentially expressed in different lung diseases. The aim of our study was to compare the concentrations of TGF-beta1 and TGF-beta2 in the BALF of patients with pneumonia and other lung diseases. Furthermore, correlation of the TGF-beta levels with the concentration of chemoattractant mediators as well as with indicators of macrophage and granulocyte activation should be investigated. Patients with pneumonia, interstitial lung disease (ILD), or chronic obstructive pulmonary diseases (COPD) were included. Patients with ischemic heart disease without pulmonary involvement served as controls. The concentrations of TGF-beta1 and TGF-beta2, of the chemoattractant cytokine IL-8, of leukotriene B4, and of the leukotrienes C4, D4, and E4 were measured. Neutrophil elastase and granulocyte content (PMN) were used as markers for granulocyte activation, and neopterin was used as a marker for the activation of macrophages. Significantly elevated levels of TGF-beta1 (mean = 0.216 ng/ml, p < 0.01) were found in patients with microbiologically positive pneumonia but not in patients with ILD or COPD. A significant (p < 0.001) correlation was found between the TGF-beta1 concentrations and the IL-8 levels and the percentage of granulocytes (r = 0.76, and r = 0.44, respectively). Elevated TGF-beta2 concentrations were measured in the BALF of patients with pneumonia (mean = 1.4 ng/ml, p < 0.01) and with ILD. Pneumonia was also associated with increased concentrations of leukotrienes C4, D4, and E4 (mean = 91.61 pg/ml, p < 0.05) and leukotriene B4 (mean = 203.9 pg/ml, p < 0.01), significantly elevated levels of PMN elastase (mean = 2958.26 ng/ml, p < 0.01), and neopterin (mean = 0.42 nmol/L). Our results strongly suggest that different lung diseases do differ with regard to the released cytokines. TGF-beta1 probably plays a key role in regulation of pulmonary inflammation, particularly in pneumonia.

A detailed protocol for the measurement of TGF-beta1 in human blood samples.

Quantification of the multifunctional cytokine Transforming Growth Factor-beta1 (TGF-beta1) in blood samples has aroused increasing interest in recent years, since an abnormal regulation of this cytokine appears to play a key role in the pathogenesis of different diseases, such as autoimmundiseases or malignant tumors. The measurement of TGF-beta1 is complicated by a lot of problems concerning the collection, preparation and handling of blood samples, the platelet contamination, and the TGF-beta1 activation procedure. Here, we recommend detailed instructions for measurement of TGF-beta1 in blood plasma samples which should be followed to exclude the determination of false positive or negative results.

Inhibitors of dipeptidyl peptidase IV/CD26 suppress activation of human MBP-specific CD4+ T cell clones.

The ectoenzyme dipeptidyl peptidase IV (DP IV, EC 3.4.14.5, CD26) has been shown to play a crucial role in T cell activation. Specific inhibitors of DP IV suppress DNA synthesis as well as cytokine production (IL-2, IL-10, IL-12, IFN-gamma) of stimulated human and mouse T cells suggesting a potential application of these effectors in transplantations and autoimmune diseases. In the present study, we have examined the expression of DP IV/CD26 on six myelin basic protein (MBP)(87-99)-specific, CD4+ T cell clones (TCC) derived from patients with multiple sclerosis (MS) as well as the biological effects of the two synthetic DP IV inhibitors Lys[Z(NO2)]-thiazolidide and Lys[Z(NO2)]-pyrrolidide on the function of these cells. All TCC expressed high levels of DP IV/CD26, as shown by flow cytometry and by enzymatic DP IV assay. Enzymatic activity of resting TCC was found to be three to fourfold higher than on resting peripheral blood T cells and close to that of T cells 48 h after PHA stimulation. The DP IV inhibitors suppress DNA synthesis and IFN-gamma, IL-4, and TNF-alpha production of the antigen-stimulated TCC. These data suggest that CD26 plays a role in regulation of activation of autoreactive TCC. Further in-vivo investigations, first in experimental models, will clarify, whether the inhibition of the enzymatic activity of DP IV could be a useful tool for therapeutic interventions in MS or other autoimmune diseases.

MRP8/MRP14, CD11b and HLA-DR expression of alveolar macrophages in pneumonia.

Activation of alveolar macrophages is characterised by specific alterations to the expression pattern of surface markers under certain pathological conditions. MRP8/MRP14 and CD11b are involved in the regulation of macrophage migration and adhesion. HLA-DR regulates the antigen presentation by alveolar macrophages. The aim of this study was to investigate the phenotype of alveolar macrophages in pneumonia particularly in relationship to the changes in concentrations of TGF-beta1 and IL-8. Using cytofluorimetry, we analysed the surface expression of MRP8/MRP14, CD11b, and HLA-DR on alveolar macrophages of 42 pneumonia (PN) patients, 14 patients with interstitial lung diseases (ILD), five patients with chronic obstructive lung disease (COPD), and 58 patients without lung disease. Phenotypic characteristics were correlated to the concentration of TGF-beta1 and IL-8 in the bronchoalveolar lavage fluid (BALF) of the same patients. The direct influence of TGF-beta1 and IL-8 on expression of MRP8/MRP14, CD11b and HLA-DR of cultured monocytes and MonoMac cells was analysed. Significantly more MRP8/MRP14 and CD11b positive macrophages and less HLA-DR-positive macrophages were found in PN but not in ILD or COPD. The percentage of CD11b-positive macrophages correlated with the TGF-beta1 as well as the IL-8 concentrations. The amount of HLA-DR-positive macrophages correlated negatively to the concentration of TGF-beta1 and IL-8. These findings document a significant activation of alveolar macrophages during pneumonia. TGF-beta1 led to a modulation of HLA-DR and MRP8/MRP14-antigen expression in vitro. In conclusion, it was shown that in pneumonia but not in ILD or COPD alveolar macrophages were characterised by an increased MRP8/MRP14 and CD11b expression and a diminished HLA-DR expression. The characterisation of subpopulations within the alveolar macrophages may be a useful tool for the monitoring of disease progression.