The oldest-old (people aged 80 or older) constituted 5 % of the population in Sweden in 2000, an increase from 1.5 % fifty years earlier. The immune system undergoes dramatic changes at high age, sometimes referred to as “immunosenescence”. However, the natures of these changes, and in particular, their clinical consequences are incompletely understood. In a previous longitudinal study, a set of immune parameters were identified and termed immune risk phenotype (IRP) because of an association with increased mortality. The IRP consists of changes in the T lymphocyte compartment, in particular an inverted CD4/CD8 ratio. The IRP was found to be associated with cytomegalovirus (CMV) infection, which through expansions of cytolytic anti-viral CD8 cell responses was ascribed a role in the development of IRP. The general aim of this thesis was to increase the knowledge of changes in the immune system and their clinical consequences in the oldest-old. The population-based random sample of the longitudinal NONA-Immune Study (n = 138, mean age 90 years at baseline) was used for all investigations. In paper I, the effects on sample size of various exclusion protocols for immune studies of the elderly was examined. The commonly used SENIEUR protocol, selecting individuals representing ‘normal ageing’, excluded 90 % of nonagenarians. Based on different protocol criteria, individuals were grouped into ‘very healthy’, ‘moderately healthy’ or ‘frail’. The prevalence of CMV was similar across the groups. Further, differentiated CD8 populations associated with CMV, i.e. those expressing CD56, CD57 and CD45RA while lacking expression of CD27 and CD28, were equally distributed across the groups of the oldest-old, but were, as expected, significantly increased in the elderly compared to a middle aged control group. The findings showed that lymphocyte subsets associated with IRP might serve as significant biomarkers of ageing independent of the overall health status, also supporting the notion that immunological studies of the oldest-old should be done in population-based non-selected populations. The IRP and the presence of low-grade inflammation, for example increase of   IL-6 in plasma, constitute major predictors of 2-year mortality in the oldest-old. In paper II, the CD4/CD8 ratio and IL-6 were found to predict 97 % of observed survival and 57 % of deaths over 2 years. The impact of IRP and IL-6 on 2-year survival was independent of age, sex and several diseases. The longitudinal design allowed temporal evaluations, suggesting a sequence of events starting with IRP and leading to inflammation in the decline state.                                      Four-year mortality in the oldest-old (paper III) was found to be mainly related to markers of inflammation and IRP. Individuals with both inverted CD4/CD8 ratio and high IL-6 level had significantly higher 4 year mortality (82 %) compared to individuals with CD4/CD8 ratio ³ 1 and low IL-6 level (29 %) at baseline. The presence of IRP and increased IL-6 level showed some associations with presence of diseases; in particular, IL6 was associated with the presence of cognitive impairment. However, despite being strong predictors of mortality, IRP and IL-6 could not be linked to any specific cause of death, probably due to the multi-factorial nature of these factors.                                                                                                                             The prevalence of antinuclear antibodies (ANA) in the oldest-old was higher compared to younger controls (paper IV). The difference across age was most pronounced in men, showing low levels at younger age, whereas the prevalence among the oldest-old men reached a similar level as in women. There was no association between the presence of ANA and IRP, CMV status or health status in the oldest-old.

Epidemiological studies have shown strong and consistent associations between exposure to air pollution and increases in morbidity and mortality. Key air pollutants that have been identified include fine particulate matter (PM) and ozone (O3), both major contributors to smog. However, there is a lack of understanding of the mechanisms involved and the relative contributions of individual pollutants. A controlled human exposure facility was used to carry out inhalation studies of concentrated ambient fine particles (CAP), O3, CAP+O3 and filtered air following a randomized design. Exposures were 2 hrs in duration at rest. Subjects included mild asthmatics and non-asthmatics. This thesis focuses on acute cardiovascular responses including blood pressure (BP), brachial artery reactivity (flow-mediated dilatation [FMD]) and markers of systemic inflammation (blood neutrophils and interleukin [IL]-6). Results showed that for CAP-containing exposures (CAP, CAP+O3) there were small but significant transient increases in diastolic BP (DBP) during exposures. Furthermore, neutrophils and IL-6 increased 1 - 3 hrs after and FMD decreased 20 hrs after CAP-containing exposures. Responses to O3 were smaller, comparable to filtered air. The data suggests that adverse responses were mainly driven by PM. The DBP increase was rapid-developing and quick to dissipate, which points to an autonomic irritant response. The magnitude of the DBP increase was strongly negatively associated with the high frequency component of heart rate variability, suggesting parasympathetic withdrawal as a mechanism. In comparison, IL-6, neutrophil and FMD responses were slower to develop, indicative of an inflammatory mechanism. An intriguing finding was that IL-6 increased 3 hrs after CAP, but not after CAP+O3. Further investigation revealed that exposure to CAP+O3 in some individuals may trigger a reflex inhibition of inspiration, decreasing their tidal volume and inhaled pollutant dose, leading to a reduction in systemic IL-6, a potential protective mechanism. Together the findings support the epidemiological evidence of adverse fine PM health effects. Many questions remain to be answered about the health effects of air pollution including a better understanding of how inhaled pollutants result in cardiovascular effects. It is hoped that the insights gained from this thesis will advance the understanding of air pollution health effects.

Epidemiological studies have shown strong and consistent associations between exposure to air pollution and increases in morbidity and mortality. Key air pollutants that have been identified include fine particulate matter (PM) and ozone (O3), both major contributors to smog. However, there is a lack of understanding of the mechanisms involved and the relative contributions of individual pollutants. A controlled human exposure facility was used to carry out inhalation studies of concentrated ambient fine particles (CAP), O3, CAP+O3 and filtered air following a randomized design. Exposures were 2 hrs in duration at rest. Subjects included mild asthmatics and non-asthmatics. This thesis focuses on acute cardiovascular responses including blood pressure (BP), brachial artery reactivity (flow-mediated dilatation [FMD]) and markers of systemic inflammation (blood neutrophils and interleukin [IL]-6). Results showed that for CAP-containing exposures (CAP, CAP+O3) there were small but significant transient increases in diastolic BP (DBP) during exposures. Furthermore, neutrophils and IL-6 increased 1 - 3 hrs after and FMD decreased 20 hrs after CAP-containing exposures. Responses to O3 were smaller, comparable to filtered air. The data suggests that adverse responses were mainly driven by PM. The DBP increase was rapid-developing and quick to dissipate, which points to an autonomic irritant response. The magnitude of the DBP increase was strongly negatively associated with the high frequency component of heart rate variability, suggesting parasympathetic withdrawal as a mechanism. In comparison, IL-6, neutrophil and FMD responses were slower to develop, indicative of an inflammatory mechanism. An intriguing finding was that IL-6 increased 3 hrs after CAP, but not after CAP+O3. Further investigation revealed that exposure to CAP+O3 in some individuals may trigger a reflex inhibition of inspiration, decreasing their tidal volume and inhaled pollutant dose, leading to a reduction in systemic IL-6, a potential protective mechanism. Together the findings support the epidemiological evidence of adverse fine PM health effects. Many questions remain to be answered about the health effects of air pollution including a better understanding of how inhaled pollutants result in cardiovascular effects. It is hoped that the insights gained from this thesis will advance the understanding of air pollution health effects.

Mathematical models of signal transduction pathways are characterized by a large number of proteins and uncertain parameters, yet only a limited amount of quantitative data is available. The dissertation addresses this problem using two different approaches: the first approach deals with a model simplification procedure for signaling pathways that reduces the model size but retains the physical interpretation of the remaining states, while the second approach deals with creating rich data sets by computing transcription factor profiles from fluorescent images of green-fluorescent-protein (GFP) reporter cells. For the first approach a model simplification procedure for signaling pathway models is presented. The technique makes use of sensitivity and observability analysis to select the retained proteins for the simplified model. The presented technique is applied to an IL-6 signaling pathway model. It is found that the model size can be significantly reduced and the simplified model is able to adequately predict the dynamics of key proteins of the signaling pathway. An approach for quantitatively determining transcription factor profiles from GFP reporter data is developed as the second major contribution of this work. The procedure analyzes fluorescent images to determine fluorescence intensity profiles using principal component analysis and K-means clustering, and then computes the transcription factor concentration from the fluorescence intensity profiles by solving an inverse problem involving a model describing transcription, translation, and activation of green fluorescent proteins. Activation profiles of the transcription factors NF-κB, nuclear STAT3, and C/EBPβ are obtained using the presented approach. The data for NF-κB is used to develop a model for TNF-α signal transduction while the data for nuclear STAT3 and C/EBPβ is used to verify the simplified IL-6 model. Finally, an approach is developed to compute the distribution of transcription factor profiles among a population of cells. This approach consists of an algorithm for identifying individual fluorescent cells from fluorescent images, and an algorithm to compute the distribution of transcription factor profiles from the fluorescence intensity distribution by solving an inverse problem. The technique is applied to experimental data to derive the distribution of NF-κB concentrations from fluorescent images of a NF-κB GFP reporter system.

Ο ρινικός πολύποδας (ΡΠ) είναι μια χρόνια φλεγμονώδης νόσος του ρινικού βλεννογόνου, η οποία χαρακτηρίζεται από διήθηση φλεγμονωδών κυττάρων, όπως ηωσινόφιλα, λεμφοκύτταρα και πλασμοκύτταρα, τροποποιήσεις στη διαφοροποίηση του επιθηλίου και ανάπλαση ιστού, που περιλαμβάνει υπερπλασία της βασικής μεμβράνης, συσσώρευση εξωκυττάριου υλικού και οίδημα. Ο παράγοντας αναστολής της μετανάστευσης μακροφάγων (MIF) είναι μία μοναδική κυτταροκίνη με σημαντικό ρόλο στο σηπτικό σόκ και στις χρόνιες φλεγμονώδεις και αυτοάνοσες ασθένειες.Παράγεται από ενεργοποιημένα Τ-κύτταρα, μακροφάγα αλλά και από ποικιλία άλλων κυττάρων. Εκτός των άλλων, έχει βρεθεί ότι επάγει την έκφραση της IL-6 από διάφορα κύτταρα και ανταγωνίζεται την κατασταλτική επίδραση των γλυκοκορτικοειδών στην έκφρασή της. Απαντάται σε αυξημένα επίπεδα στο ρινικό πολύποδα. Ο αυξητικός παράγοντας μετασχηματισμού-β1 (TGF-β1) θεωρείται ένας αντιφλεγμονώδης παράγοντες, ο οποίος ανταγωνίζεται τη δράση της IL-1β και του TNF-α, στην έκφραση της ΜΜΡ-1 και ΜΜΡ-3. Διεγείρει επίσης την έκφραση του ΤΙΜΡ-1, του κολλαγόνου τύπου Ι και της IL-6 και λόγω των δράσεών του αυτών εμπλέκεται ισχυρά στις διαδικασίες ίνωσης. Απαντάται σε σημαντικά επίπεδα στο ρινικό πολύποδα. Η IL-6 είναι μία Th2 πολυλειτουργική κυτταροκίνη η οποία εμπλέκεται σε ποικίλες φλεγμονώδεις καταστάσεις. Διεγείρει την ανάπτυξη των ινοβλαστών, αυξάνει τη σύνθεση και εναπόθεση του κολλαγόνου και μειώνει την αποικοδόμησή του. Απαντάται σε αυξημένα επίπεδα στο ρινικό πολύποδα και θεωρείται σημαντικός παθαγενετικός παράγοντας μέσω της επαγωγής του σχηματισμού των πλασμοκυττάρων και της σύνθεσης συστατικών του στρώματος, και της προαγωγής της σύνθεσης και εναπόθεσης κολλαγόνου και της ανάπλασης ιστού. Σκοπός της παρούσης εργασίας είναι η μελέτη της συμβολής του MIF και του TGF-β1 στη παραγωγή της IL-6 από ινοβλάστες ρινικού πολύποδα, των σηματοδοτικών μονοπατιών που εμπλέκονται, και η διερεύνηση της πιθανής συνεργειακής δράσης τους στην έκφραση της κυτταροκίνης. Τόσο ο TGF-β1 (0,01-1 ng/ml) όσο και ο MIF (1-100 ng/ml) προκάλεσαν διέγερση της έκφραση της IL-6 σε ινοβλάστες ρινικού πολύποδα κατά δοσοεξαρτώμενο τρόπο, η οποία κατεστάλλει σημαντικά από αναστολέις των ΜΑΡ κινασών και της ΡΙ-3 κινάσης. Ο TGF-β1 (1 ng/ml) προκάλεσε επίσης χρονοεξαρτώμενη αύξηση στα επίπεδα της IL-6 γιά χρόνο επώασης μέχρι 2 ώρες, τα οποιά έμεινα σταθερά στη συνέχεια μέχρι τις 72 ώρες επώασης, επαγωγή της παραγωγής ενδοκυτταρικών ενεργών ειδών οξυγόνου (ROS) με μέγιστο σε δύο χρόνους επώασης 20 και 180 λεπτά, και ενεργοποίηση των ERK κινασών από 15-60 λεπτά επώασης, με μέγιστη ενεργοποίηση στα 30 λεπτά, και στη συνέχεια πτώση στα επίπεδα του μάρτυρα. Ενώ ο MIF σε συγκέντρωση 1-100 ng/ml προκάλεσε μικρή μείωση στην έκφραση της φωσφατάσης-1 των ΜΑΡΚ (ΜΚΡ-1), ο TGF-β1 αντίθετα, σε συγκέντρωση 1 ng/ml προκάλεσε αύξηση στην έκφραση της ΜΚΡ-1 σε δύο χρόνους επώασης 0,5 και 24 ώρες. Μετά από επώαση των ινοβλαστών ρινικού πολύποδα παρουσία TGF-β1 (1 ng/ml) και MIF (100 ng/ml) μαζί, δεν παρατηρήθηκε συνεργειακή επίδραση στην έκφραση της IL-6. Ενώ τόσο ο TGF-β1 όσο και ο MIF προκάλεσαν διέγερση στην έκφραση της IL-6 από ινοβλάστες πνεύμονα, δεν παρατηρήθηκε και πάλι συνεργειακή επίδρασή τους στην έκφραση της κυτταροκίνης αυτής. Συμπερασματικά, φαίνεται ότι ο MIF, ενώ ανταγωνίζεται την κατασταλτική επίδραση των γλυκοκορτικοειδών στην έκφραση της IL-6 μέσω της ρύθμισης των επιπέδων της ΜΚΡ-1, δεν έχει την ίδια επίδραση στην έκφραση της IL-6 από τον TGF-β1, μέσω ρύθμισης της έκφρασης της φωσφατάσης αυτής. Από την άλλη μεριά η επαγωγή της έκφρασης της ΜΚΡ-1 από τον TGF-β1 φαίνεται να μην επηρεάζει την παραγωγή της IL-6 για μικρούς χρόνους επώασης, μέχρι 2 ώρες, πιθανόν λόγω της ανασταλτικής επίδρασης των ROS, που επάγονται από τον TGF-β1, στη δράση της ΜΚΡ-1, ενώ την επηρεάζει για μεγάλους χρόνους επώασης , εξ ού και τα σταθερά επίπεδα της IL-6 μέχρι και 72 ώρες επώασης. / Nasal polyp (NP) is a chronic inflammatory condition of nasal mucosa, characterized by infiltration of inflammatory cells such as eosinophils, lymphocytes and plasma cells, alterations in epithelial differentiation and tissue reconstruction, involving hyperplasia of basal membrane, accumulation of extracellular material and edema. Macrophage migration inhibitory factor (MIF) is a unique cytokine, the role of which in chronic inflammatory and autoimmune diseases and septic shock pathogenesis is very important. MIF is produced by activated T-lymphocytes, macrophages and a plethora of other cells. MIF appears to antagonize the suppressive effect of glucocorticoids as well as induce the expression of IL-6 in multiple cells. High levels of MIF are detected in nasal polyps. Transforming growth factor- β1 (TGF-β1) is an anti-inflammatory factor antagonizing the positive effect of IL-1β and TNF-α on the expression of MMP-1 and MMP-3, TGF-β1 also stimulates the expression of TIMP-1, collagen type I and IL-6; because of these effects, TGF-β1 is involved in the process of fibrosis. TGF-β1 levels in nasal polyps are significantly elevated. IL-6 is a cytokine participating in Th2 response and consequently is involved in a subset of inflammatory reactions. IL-6 stimulates the growth of fibroblasts, increases the production and deposition of collagen and it decreases its degradation. IL-6 is found in nasal polyps at elevated levels and it is thought to be an important pathogenic factor acting mainly in tissue reconstruction, stimulation of plasma cell differentiation, production of stromal material, promotion of collagen synthesis and deposition. The purpose of this paper is to study the effect of MIF and TGF-β1 in IL-6 production by fibroblasts isolated from nasal polyps, dissect the signaling pathways involved, and investigate their synergistic effect on the production of IL-6. Both TGF-β1 (0, 01-1 ng/ml) and MIF (1-100 ng/ml) induced IL-6 expression in nasal polyp fibroblasts in a dose-dependent manner. This effect was significantly suppressed by inhibitors of MAP and PI-3 kinase pathways. TGF-β1 (1 ng/ml) also induced IL-6 expression within 2 hours of administration. Elevated IL-6 levels remained unchanged for 72h further. TGF-β1 also promoted the production of intracellular reactive oxygen species (ROS), which peaked in 20 and 180 minutes and the activation of ERK kinase, peaked in 30 minutes. While MIF, at a concentration of 1-100 ng/ml, caused a slight decrease in the expression of phospatase-1 of MAPK (MKP-1), TGF-β1, at a concentration of 1 ng/ml, increased the expression of MKP-1. No synergistic effect on IL-6 expression was detected after incubating nasal polyp and lung fibroblasts together with TGF-β1 (1 ng/ml) and MIF (100 ng/ml). In conclusion, while MIF antagonizes the suppressive effect of glucocorticoids on the expression of IL-6 by regulating the levels of MKP-1, it fails to antagonize the TGF-β1 inducing effect on IL-6 via MKP-1. The induction of MKP-1expression by TGF-β1 is not affecting the production of IL-6 after short incubation periods; this effect can be explained by the inhibitory effect of TGF-β1 induced ROS on MKP-1. After prolong incubation with TGF-β1 (up to 72 hours), IL-6 levels remain elevated.

La schizophrénie est une maladie mentale grave qui présente une comorbidité fréquente avec la toxicomanie et avec divers troubles immunitaires. Une méta-analyse réalisée récemment dans notre laboratoire a montré une augmentation d’IL-6 (une cytokine pro-inflammatoire), du récepteur soluble d’IL-2 (un marqueur d’activation du système immunitaire), et d’IL-1RA (une cytokine anti-inflammatoire) dans la schizophrénie, suggérant l’existence d’un syndrome inflammatoire dans cette maladie. La toxicomanie aussi est associée au dérèglement du réseau des cytokines inflammatoires, mais les effets dépendent du type de drogues et ils sont parfois diamétralement opposés. On dispose encore de peu d’informations sur le statut immunitaire et inflammatoire des patients qui ont un double diagnostic de schizophrénie et de toxicomanie. Le but de ce travail était d’explorer l’existence d’un état inflammatoire systémique chez les patients schizophrènes et toxicomanes, et l’influence du traitement avec un médicament antipsychotique atypique, la quétiapine. Les objectifs spécifiques étaient : 1) Mesurer les concentrations plasmatiques des cytokines inflammatoires chez les schizophrènes et toxicomanes avant, pendant et après traitement avec la quétiapine ; et 2) Faire des études de corrélations entre les taux de cytokines, les symptômes cliniques, et la consommation de drogues. Les résultats montrent que comparativement aux contrôles normaux, les patients avec un double diagnostic présentent une augmentation d’IL-6, d’IL-1RA, du sIL-2R et d’IL-8 avant traitement à la quétiapine. Les augmentations des concentrations plasmatiques d’IL-1RA sont particulièrement importantes chez les patients avec double diagnostic, si on les compare à celles publiées chez les schizophrènes sans toxicomanie. Le traitement à la quétiapine n’influence pas les concentrations plasmatiques de ces cytokines, sauf sIL-2R qui augmente davantage au cours du traitement. Des corrélations positives de puissance modérée sont retrouvées entre IL-6 et dépression, IL-6 et alcool, IL-1RA et cognition, IL-8 et dépression, IL-8 et alcool, sIL-2R et cannabis. Notre étude révèle que la réponse inflammatoire est activée chez les schizophrènes et toxicomanes. De plus, la toxicomanie semble jouer un rôle facilitant ou potentialisateur dans les augmentations des taux circulants d’IL-1RA. Les études en cours sur différentes populations de schizophrènes avec ou sans toxicomanie, et chez des toxicomanes non schizophrènes permettront de préciser le rôle des différentes drogues d’abus dans le syndrome inflammatoire chez les schizophrènes, ainsi que les implications de ce syndrome sur le plan clinique et thérapeutique. / Schizophrenia is a psychosis which presents a frequent comorbidity with substance use disorders (SUD) and with various immune alterations. Using meta-analysis, we have demonstrated previously establishment of an inflammatory syndrome in schizophrenia patients, illustrated by elevated circulating levels of IL-6 (a pro-inflammatory cytokine), sIL-2R (marker of immune activation) and IL-1RA (an anti-inflammatory cytokine). SUD is also associated with dysregulation of inflammatory cytokines, but the effects may depend on the type of substance of abuse. The goal of this project was: 1) To measure plasma concentrations of inflammatory cytokines in schizophrenia patients with comorbid SUD, before, during and after treatment with an atypical antipsychotic, quetiapine; and 2) To perform correlation studies between plasma concentrations of inflammatory cytokines and clinical symptoms, including positive and negative symptoms, cognition, depression and substance use. Relative to normal controls, patients with a dual diagnosis showed increased plasma concentrations of IL-6, IL-1RA, sIL-2R, and IL-8 at baseline, IL-1RA increases being the most important. Quetiapine treatment did not influence plasma cytokine concentrations, except sIL-2R which increased further. Moderate positive correlations were found between IL-6 and depression, IL-6 and alcohol, IL-1RA and cognition, IL-8 and depression, IL-8 and alcohol and between sIL-2R and cannabis. This study demonstrates that the immune and inflammatory response is activated in schizophrenia patients with comorbid SUD. Furthermore, SUD may play a facilitating or potentiating role in the increases in peripheral levels of IL-1RA. Ongoing studies in different patient populations with schizophrenia with or without SUD, and patients with SUD alone will help elucidate the role of different substances of abuse in the inflammatory syndrome in schizophrenia, as well as the clinical and therapeutic relevance of this syndrome.

No description available.

L'objectif des travaux de cette thèse a été d'explorer les bases moléculaires de l'effet de l'huile d'Argan (HA) sur le métabolisme lipidique au niveau mitochondriale et peroxysomale ainsi qu'élucider son potentiel anti-inflammatoire. Nous avons donc montré, dans un premier temps, que les méthodes artisanales préservaient les propriétés antioxydantes d'HA empêchant l'oxydation de l'acide férulique contrairement à l'HA d'origines commerciale. Ensuite, le traitement par l'HA ou par les lipopolysaccharides (LPS) de fibroblastes humains, un modèle cellulaire de la pseudo-adrénoleucodystrophie néonatale (P-NALD), révèle pour l'HA une prolifération des peroxysomes indépendante de l'activation du récepteur nucléaire PPARα et de son coactivateur PGC-1α. Par contre, l'induction de la prolifération de peroxysomes par les LPS est accompagnée d'une activation de PPAR et de PGC-1Parallèlement, une étude a été réalisée au niveau hépatique chez des souris traitées par l'HA ou par les LPS. Nous avons montré pour la première fois l'activité antioxydante de l'huile d'Argan in vivo au niveau hépatique par l'induction de l'activité enzymatique de la catalase peroxysomale et une activité hypolipémiante par la stimulation des activités déshydrogénases (ACADs) de la -oxydations mitochondriale des acides gars. De plus, l'HA induit la transcription des gènes PPECK et G6PH de la voie de la néoglucogenèse. Nous avons montré également pour la première fois un effet préventif de l'HA contre la répression des activités déshydrogénases des voies de -oxydations mitochondriale et peroxysomale, ainsi que celle la voie de la néoglucogenèse. Nos travaux démontrent que l'HA possède un potentiel anti-inflammatoire, induit par le LPS, élucidé par la répression de cytokines pro-inflammatoires IL-6 et TNFα et par l'induction de cytokines anti-inflammatoires IL10 et IL-4. L'ensemble de nos résultats indiquerait que l'huile d'Argan, du fait de sa composition riche en acide gras mono et polyinsaturés et en antioxydants, a des effets hypolipémiants et anti-inflammatoires au niveau hépatique qui se traduisent par une régulation de l'expression à la fois de récepteurs nucléaires et de leur gènes cibles ainsi que de certaines cytokines

No description available.

Abstract The aims of this study were to investigate the clinical features, the endoscopic and histological abnormalities of ileocolonic and gastroduodenal mucosa and immunogenetic background of microscopic colitis (MC) and its subtypes collagenous colitis (CC) and lymphocytic colitis (LC). 30 patients with CC and 54 with LC were examined with different control groups used according to the study. The mean age at diagnosis was in the sixties in both CC and LC, with a female preponderance in both Autoimmune conditions such as celiac diseased (CD) were common in MC. Bronchial asthma associated with LC. Lactose intolerance associated with MC but colonic diverticulosis was rare. Ileal histological changes were common in MC. Focal gastritis did not associate with MC. Lymphocytic gastritis was found only in LC. Gastric endoscopic erosions were more prevalent in CC than in LC. The age at diagnosis of MC was higher in H. pylori positive than negative patients. The patients with MC had shorter duodenal villi than controls even when patients with CD were excluded. HLA-DR3-DQ2 haplotype and TNF2 allele carriage were more frequent in patients with MC compared to controls. The genotype GG of IL-6-174 was more prevalent in MC compared to the controls. IL-6 genotype did not associate with the serum IL-6 concentration. The concentration of IL-6 was higher in patients with CC than in LC. In conclusion, in addition to colonic typical inflammation, histological abnormalities were detected also in gastric, duodenal and ileal mucosa. CD was common in MC, but there was no association with specific types of gastritis. HLA association was found in MC. Polymorphism in the proinflammatory IL-6-174 gene displayed a possible association with MC. Although CC and LC share many clinical features, the differences in the occurrence of immune conditions, gastric abnormalities and IL-6 response point to differences in their pathogenesis. / Tiivistelmä Tutkimuksen tavoitteena oli tutkia mikroskooppisen koliitin sekä sen alaryhmien, kollageenikoliitin ja lymfosyyttisen koliitin kliinisiä piirteitä, mahalaukun ja ohutsuolen limakalvon muutoksia sekä immunogeneettistä taustaa. Tutkimukseen osallistui 30 kollageeni- ja 54 lymfosyyttikoliittipotilasta sekä verrokkeja. Sekä kollageenikoliitti että lymfosyyttinen koliitti diagnosoitiin keskimäärin 50–60 v iässä, ja molemmissa tautiryhmissä naisia oli enemmän kuin miehiä. Autoimmuunisairaudet kuten keliakia olivat yleisiä liitännäissairauksia. Astmaa esiintyi lymfosyyttistä koliittia sairastavilla verrokkeja enemmän. Laktoosi-intoleranssi oli yleistä, mutta paksusuolen divertikuloosia oli harvoin mikroskooppista koliittia sairastavilla potilailla. Ileumin muutokset olivat yleisiä. Mikroskooppinen koliitti ei assosioitunut fokaaliseen gastriittiin. Lymfosyyttigastriittia todettiin vain lymfosyyttisessä koliitissa. Mahalaukun eroosioita esiintyi enemmän kollageenikoliitissa kuin lymfosyyttisessa koliitissa. Mikroskooppinen koliitti ilmeni iäkkäämpänä niillä, joilla todettiin helikobakteeri. Pohjukaissuolen suolinukka oli keliakiasta riippumatta matalampaa kuin verrokeilla. HLA-DR3-DQ2 haplotyyppiä, TNF-2 alleelia ja IL-6-174-GG genotyyppiä esiintyi enemmmän mikroskooppista koliittia sairastavilla potilailla kuin verrokeilla. IL-6 genotyyppi ei vaikuttanut seerumin IL-6-pitoisuuteen. IL-6 pitoisuus oli korkeampi kollageenikoliitissa kuin lymfosyyttisessä koliitissa. Havainnot osoittavat, että mikroskooppisessa koliitissa limakalvomuutoksia on paksusuolen lisäksi myös muualla mahasuolikanavassa. Keliakia on tavallinen liitännäistauti. HLA-DR3-DQ2 on yleinen mikroskooppista koliittia sairastavilla myös ilman keliakiaa. IL-6-174-GG genotyypin yleisyys viittaa siihen, että tämä polymorfismi saattaa altistaa mikroskooppiselle koliitille. Vaikka kollageenikoliitti ja lymfosyyttinen koliitti ovat kliinisesti samankaltaisia sairauksia, erot tautiassosiaatioissa, mahan limakalvon muutoksissa ja seerumin IL-6-tasoissa viittaavat erilaisiin syntymekanismeihin.