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A study of the HLA-A, -B, -C, and -DR antigens in patients with Crohn's disease and controls did not reveal a significant strong association with a particular HLA antigens. A segregation analysis of parental HLA haplotypes in nine families with at least two children suffering from Crohn's disease did not show a significant deviation from the expected Mendelian segregation.

Oxidative damage has been implicated in the pathogenesis of inflammatory bowel disease. In the present study sulphasalazine and mesalazine (5-aminosalicylic acid) in vitro were shown to possess scavenging activity and to attenuate the production of oxygen metabolites by neutrophils. In a double-blind randomized crossover study, with five patients with inflammatory bowel disease in remission and four healthy controls, we evaluated the influence of in vivo administration of sulphasalazine and mesalazine on the neutrophil oxygen metabolite production in vitro. Apart from a small but significant increase in the neutrophil H2O2 and O2 production by sulphasalazine, in particular in controls, in vivo administration of both drugs hardly affected the oxygen metabolite-producing capacity of the cells. This observation was confirmed by in vitro preincubation of neutrophils with the drugs and subsequent oxygen metabolite production analysis. It is concluded that sulphasalazine and mesalazine do not influence the oxidative capacity of neutrophils, but scavenge and attenuate the production of oxygen metabolites when present in the immediate surroundings of the cells. Thus, protection against oxidative damage is definitely one of the modes of action of these drugs.

The effect of perioperative blood transfusion on recurrence after primary operation was retrospectively studied in a group of 104 patients with Crohn's disease. Patients who had minor procedures like strictureplasty, segmental small-bowel resection, and operation for perianal fistula were excluded. Patients who had more extensive surgery were selected, to have an approximately equal distribution of blood transfusion in the different subgroups. Sixty-six female and 45 male patients were included; 65 patients had perioperative blood transfusion and 39 did not. Irrespective of blood transfusion it was confirmed that patients with small-bowel localization have a better prognosis than patients with combined or colonic localization. Patients who had resection of a specimen of less than 30 cm or more than 70 cm had a worse prognosis than the others. The reason for this observation is unclear. Except for patients with colonic localization only, blood transfusion was about equally distributed among patients with ileocaecal localization (19 of 36) and patients with ileal disease (17 of 34). Perioperative blood transfusion had no effect on disease recurrence, either for the whole group of transfused patients or for any of the subgroups, apart from those with colonic localization only. They had a significantly lower recurrence, as diagnosed before 60 months of follow-up. This is ascribed to the fact that these patients had large colonic resection with a lower chance of having active recurrent disease. In conclusion, we could not confirm the protective effects of blood transfusion on recurrence of Crohn's disease, as observed by others.

Six hundred and seventy one patients (52.5% women) with Crohn's disease seen at Leiden University Hospital between 1934 and 1984 were identified. Follow up was 98.2% complete. Sixty four (9.7%) of the 659 patients died. The cause of death was related to Crohn's disease in 34 patients, probably related to the disease in four, and unrelated, from incidental causes, in 25. The cause of death could not be identified in one patient. There was a significant decrease of deaths related to the disease after 1973. Causes of death such as amyloidosis and malnutrition have disappeared and postoperative deaths have decreased. The standardised mortality ratio showed an excess mortality of 2.23 for all patients. It was higher for women (3.30) than for men (1.76). A comparison of two recent 10 year periods showed a significant decrease in standardised mortality ratio in men but not in women. Patients whose disease started before the age of 20 years had an excess mortality compared with older patients. This study supports the view that the prognosis of Crohn's disease has improved in general but high quality medical and surgical management is important particularly for younger patients.

Indium-111 autologous leucocyte scanning is a non-invasive and reliable technique for the detection of abdominal abscesses. In the past decade several papers have been published concerning the use of this technique in the assessment of inflammatory bowel disease (IBD) with variable results. We conducted a prospective study of 62 patients with IBD attending the Leiden University Hospital, to assess the diagnostic value of indium-111 tropolonate autologous granulocyte scanning. Fifty-one patients had Crohn's disease (CD) (30 with involvement of the small bowel, 18 the colon only, and 3 patients had both localizations), and 11 had ulcerative colitis (UC). Twenty-one of 26 patients with evidence of active disease of the small intestine had a true-positive scan (sensitivity, 80%). However, accurate assessment of localization and extent of disease were often difficult. The other five patients had a false-negative scan. Seven patients had a true-negative scan. No false-positive scans were found. Thus, the diagno...

Decreased cell mediated cytotoxicity occurs frequently in inflammatory bowel disease, particularly in patients with active disease. It is not clear, however, whether this decrease is caused by the disease or is a consequence of the medical treatment. In this study we evaluated the effect of in vivo treatment with 5-aminosalicylic acid and sulphasalazine on the in vitro natural killer cell activity in five patients with inflammatory bowel disease in remission and in four healthy control subjects in a double blind randomised crossover trial preceded and separated by four weeks of treatment with placebo. The natural killer cell activity was significantly impaired in 67% (six of nine subjects) after four weeks' sulphasalazine treatment and tended to be related to subjects with a slow acetylator phenotype. In contrast, 5-aminosalicylic acid treatment caused only a marginal reaction in the natural killer cell activity in 22% (two of nine subjects). The inhibitory effects were found to be reversible since the decreased natural killer cell activity was completely restored after placebo treatment in all subjects. In conclusion, in vivo treatment with sulphasalazine inhibits the in vitro natural killer cell activity and this seems to be mediated by the sulphapyridine moiety. This phenomenon may contribute to the low natural killer cell activity found in patients with active inflammatory bowel disease.

Plasma fibronectin concentrations were measured by an ELISA method in two groups of patients with Crohn's disease. In the first study the value of fibronectin as acute phase protein was determined in 48 patients. There was a poor but significant correlation (r = 0.294, p = 0.043) between disease activity and fibronectin concentration in these patients. However, fibronectin was found to show the best correlation with the disease activity of eight acute phase parameters tested. In the second study, the relation between development or presence of fibrosis/stenosis in the intestine of 91 patients with Crohn's disease was related to the plasma fibronectin concentration. The incidence of this type of lesion was found to increase with the level of fibronectin in the plasma together with the disease history of these patients, in particular when intestinal resection had to be performed. These observations reveal that assessment of fibronectin in plasma of patients with Crohn's disease is of limited value for the determination of disease activity, but that its concentration is related to the biological behavior, i.e. formation of fibrosis/stenosis, of the inflammatory lesion.

Crohn's disease is a chronic inflammatory granulomatous disorder affecting any part of the gastrointestinal tract, particularly the terminal ileum and the colon. Familiar complications are strictures, fistulae, perforation, haemorrhages and malabsorption due to multiple resections. A patient with two rare complications of Crohn's disease is described. A 16-year-old female with ileocaecal Crohn's disease presented with anaemia and ileus. This ileus was caused by some 40 tablets of ferrosulphate with a non-soluble matrix, in the presence of an existing stenosis of the ileum due to Crohn's disease. An ileocaecal resection was performed. During an exacerbation of Crohn's disease she developed hepatic vein thrombosis with a Budd-Chiari syndrome (upper abdominal pain, hepatomegaly and ascites). Prescription of tablets with a non-soluble matrix is contraindicated in patients with a partial stenosis of the intestine. Patients with active Crohn's disease are predisposed to thromboembolic complications. Hepatic vein thrombosis in our patient may have been the result of hypercoagulability during the exacerbation of her disease.

Indium-111 autologous leucocyte scanning is a non-invasive and reliable technique for the detection of abdominal abscesses. In the past decade several papers have been published concerning the use of this technique in the assessment of inflammatory bowel disease (IBD) with variable results. We conducted a prospective study of 62 patients with IBD attending the Leiden University Hospital, to assess the diagnostic value of indium-111 tropolonate autologous granulocyte scanning. Fifty-one patients had Crohn's disease (CD) (30 with involvement of the small bowel, 18 the colon only, and 3 patients had both localizations), and 11 had ulcerative colitis (UC). Twenty-one of 26 patients with evidence of active disease of the small intestine had a true-positive scan (sensitivity, 80%). However, accurate assessment of localization and extent of disease were often difficult. The other five patients had a false-negative scan. Seven patients had a true-negative scan. No false-positive scans were found. Thus, the diagnostic accuracy for small-intestinal Crohn's disease was 85%. In contrast, of 32 patients with colonic disease (CD and UC), 26 had a true-positive scan corresponding in localization and extent with standard investigations, 3 patients had a false-negative scan (sensitivity, 90%), and 3 had a true-negative scan (diagnostic accuracy, 91%). The patients' acceptability of this procedure was definitely superior to that for radiology and endoscopy. In conclusion, this technique has a definite place in evaluating localization and extent of active colonic disease and in severely ill patients in whom invasive techniques are contraindicated.(ABSTRACT TRUNCATED AT 250 WORDS)

To determine whether patients with Crohn’s disease and ulcerative colitis dif-fere in their capacity to produce immunoglobulins, we have studied the in vitro immunoglobulin synthesis by peripheral blood lymphocytes of such patients and compared the results with those of healthy controls. The spontaneous immunoglobulin production by peripheral blood lymphocytes from Crohn’s disease patients was significantly increased for both IgA and IgG, whereas for IgM the increase did not reach statistical significance. In ulcerative colitis, however, the spontaneous IgA and IgG production was almost identical to that of the healthy controls and thus lower than in Crohn’s disease. Pokeweed mitogen stimulation resulted in a significantly enhanced immunoglobulin production in Crohn’s disease and in controls, whereas peripheral blood lymphocytes from ulcerative colitis patients were found to be rather insensitive to pokeweed mitogen stimulation. Suppression of the stimulated immunoglobulin production by concanavalin A revealed considerable reduction in all groups studied. In general, the highest suppression was found in patients with Crohn’s disease. In patients with Crohn’s disease or ulcerative colitis there was no relation between the changes in the in vitro immunoglobulin synthesis and the population of B or T lymphocytes and monocytes present in the peripheral blood. The differences in the spontaneous and stimulated immunoglobulin synthesis by peripheral blood lymphocytes, as found in this study, point to major changes in the regulation of the immunoglobulin synthesis in Crohn’s disease and ulcerative colitis.

Two hundred and seventy five patients with Crohn's disease from five countries were interviewed. Each patient was matched with a control of the same age. Of the 275 women with Crohn's disease 224 had been married at some time compared with 208 controls. The mean age at marriage was 23 years. Diagnosis of Crohn's disease was made five years later and the survey was conducted on average 16 years after marriage. Cases and controls had a similar obstetric study before diagnosis. After diagnosis there was a significant reduction in the number of children born to patients (0.4) compared with controls (0.7). Crohn's disease did not increase the rate of miscarriage or Caesarean section but prematurity was more common in patients (16%) than controls (7%). The site of disease at diagnosis did not affect these findings. Medical advice against pregnancy may be partly responsible for this reduction in fertility, but patients practised contraception less than controls and a significantly greater proportion of these (42%) failed to become pregnant compared with controls (28%). Crohn's disease results in subfertility.This study investigated fertility and pregnancy outcomes in 275 women with Crohn's disease from 5 European countries and in 275 age-matched controls. The mean age at marriage was 23 years among both cases and controls. Diagnosis was Crohn's disease was made an average of 5 years after marriage; this survey was conducted an average of 16 years after marriage. Although cases and controls had similar obstetric histories before diagnosis, after diagnosis there was a significant reduction in the number of children born to cases. 42% of married women with Crohn's disease who did not use contraception failed to become pregnant in the post-diagnosis period compared with 28% of controls in the same period. Crohn's disease did not increase the rates of miscarriage or Cesarean section, but prematurity was more common among cases (16%) than controls (7%). The site of disease did not influence these findings. These findings strongly suggest that Crohn's disease is associated with subfertility.

SummaryPlasminogen activators were determined in intestinal tissue, obtained after surgery from patients with Crohn’s disease and ulcerative colitis, and compared with normal intestinal tissue from colorectal cancer patients.The activity and quantity of tissue-plasminogen activator (t-PA) was found to decrease with the severity of inflammation in the patients with inflammatory bowel disease. Urokinase (u-PA) activity, however, was not changed compared with controls or in relation with severity of inflammation. In contrast, the level of u-PA antigen was found to be increased significantly in the inflammatory bowel disease tissues and was also related with severity of inflammation. The difference between u-PA activity and antigen in inflammatory bowel disease tissue could be attributed to an increase in inactive pro-u-PA and u-PA-inhibitor complexes.This increase in u-PA and the concomitant decrease in t-PA, are similar to those found in premalignant colonic adenomas, and might be related to the known increased cancer risk in inflammatory bowel disease.

The present study was undertaken to determine the value of indium-111 granulocyte scintigraphy in Crohn's disease of the small bowel by comparing the results with those of radiology, endoscopy and surgery. Twenty-one patients with Crohn's disease of the small bowel, 9 patients with Crohn's disease of the colon, 1 patient with both localizations and 8 with ulcerative colitis were studied by indium-111 granulocyte scanning. Eighteen patients had evidence of active small intestinal disease based on clinical, radiologic, and/or endoscopic, and/or histopathological features. Thirteen of them had a true positive scan (sensitivity 72%), but accurate assessment of localization and extent of disease was often difficult. Five patients had a false negative scan and 4 a true negative. No false positive scans were found. The diagnostic accuracy was 77%. In contrast, from 18 patients with colonic disease, 16 had a true positive scan corresponding in localization and extent with standard investigations, 1 patient had a false negative scan (sensitivity 94%), and 1 a true negative (diagnostic accuracy 95%). This study also showed that 3-5 h scanning after injection of indium-111-labeled granulocytes is the optimal timing for this test. The patient's acceptability of this procedure was definitely superior to radiology and endoscopy. In conclusion, this technique has a definite place in evaluating localization and extent of active colonic disease, but it does not replace good small bowel radiology and should not be recommended in the routine diagnostic workup of Crohn's disease of the small intestine.

This study was undertaken to investigate the influence of various parameters of injected autologous 111In labelled granulocytes on scintigraphic image quality. Forty-two scintigrams of 37 patients with inflammatory bowel disease were evaluated. The images were divided into three groups according to quality: good, intermediate and poor. The relationships between image quality and such radiopharmaceutical parameters as injected dose of 111In, number of injected cells and specific activity were investigated. It appeared that in order to obtain interpretable images, a specific activity of at least 85 kBq 111In/million cells was necessary. The activity of the injected dose must exceed 7 MBq if poor quality images and very long acquisition times are to be avoided.

We have investigated the correlation of 24 h and 48 h faecal Indium-111 excretion with each other and with several clinical activity indices for Crohn's disease (CD): Crohn's disease activity index (CDAI), activity index (AI), simple index (SI), Oxford score, and laboratory parameters, such as ESR, serum albumin, orosomucoid, C-reactive protein, alpha-l-antitrypsin (alpha 1-AT) faecal concentration, and alpha 1-AT clearance in 58 CD patients (37 with small bowel and 21 with colonic disease). A significant correlation was found between 24 and 48 h faecal Indium-111 excretion for small bowel (r = 0.708, p less than 0.0001) and colonic disease (r = 0.994, p less than 0.0001). The median faecal Indium-111 excretion for colonic involvement (4%; 0.15-50% median and range) was significantly (p less than 0.005) higher than that for small bowel disease (0.45%; 0.03-2.9%). No significant correlation was found between faecal Indium-111 excretion and any activity index in the patients with small bowel disease, while in the group of patients with colonic localisation only the AI showed a significant correlation (r = 0.593, p less than 0.02). Faecal Indium-111 excretion was significantly correlated with alpha 1-AT clearance (r = 0.712, p less than 0.0001) and faecal alpha 1-AT concentration (r = 0.750, p less than 0.0001) in small bowel and in colonic localisation (r = 0.530, p less than 0.02 and r = 0.444, p less than 0.05). Serum albumin was significantly correlated only in the group of patients with colonic disease (r = -0.593, p less than 0.05). The present study shows poor agreement between activity indices, serum parameters of activity and faecal Indium-111 excretion. As a good correlation was found with the alpha1-clearance, which reflects losses into the gut, these results may suggest that faecal Indium excretion does not only reflect activity of inflammation, but my relate to the extent of intestinal ulceration.

Biopsies of apparently normal buccal mucosa were taken from 14 patients with Crohn's disease and 13 healthy controls who were matched for dental status. Most patients had an increased number of lymphocytes around vessels in the subepithelial tissue and two showed fibrosis with moderate atrophy of minor glands. Plasma cells which contained immunoglobulin, predominantly IgA, were only found around minor salivary glands in both patients and controls. Quantitative studies showed a significant increase in the number of cells containing IgA in patients compared with controls. No correlation was found between immunoglobulin pattern and disease activity, age, sex, or duration of Crohn's disease. A significant correlation was found between the activity of the disease, as defined by the Crohn's Disease Activity Index, and the number of plasma cells containing IgM.

Sera from patients with Crohn's disease have been reported to show positive immunofluorescence with lymph nodes of nude mice primed with a filtrate of intestinal tissue affected with Crohn's disease. An indirect immunofluorescence assay was used to test sera of 63 unrelated patients with Crohn's disease, 21 with ulcerative colitis and 36 control subjects against lymph nodes of athymic nude (nu/nu) mice which had been injected with Crohn's disease and ulcerative colitis intestinal tissue filtrates. Forty nine per cent of Crohn's disease patients, 10% of ulcerative colitis patients and 3% of control sera reacted against lymph nodes of mice injected injected with ulcerative colitis intestinal tissue filtrates, 18% of Crohn's disease sera were with intestinal tissue homogenate from Dutch Crohn's patients. With the lymph nodes of mice injected with ulcerative colitis intestinal tissue filtrates, 18% of Crohn's disease sera were positive, whereas all ulcerative colitis and control sera were negative. Lymph nodes from 18 of the 19 mice injected with Crohn's disease tissue filtrates reacted with Crohn's disease sera, whereas only three of these 19 mice reacted with ulcerative colitis sera. A comparative study, carried out in parallel with Crohn's disease filtrate induced hyperplastic lymph nodes from the Bilthoven colony (W2) and from the New York colony (E671) using sera from 54 Crohn's disease patients from Leiden, showed immunoreactivity with 44 and 57% of the Crohn's disease sera against the two hyperplastic lymph nodes. Thirty six of the 54 Crohn's disease sera (67%) reacted with either or both lymph nodes. Only 11% of the Crohn's disease sera which were examined for immunofluorescence and lymphocytotoxic antibodies had lymphocytotoxic antibodies, whereas 40% and 46% of the same sera showed positive immunofluorescence against E671 and W2, respectively. Absorption studies indicated that lymphocytotoxic antibodies activity and the immunofluorescence against the primed nude mouse lymph node are mediated by different serum antibodies in Crohn's disease. The reproducibility of the nude mouse immunofluorescence test system for a preferential immunoreactivity of Crohn's disease sera against Crohn's disease tissue primed murine lymph nodes has been confirmed by the present study. Further studies are necessary to find out whether crossreactive antigen(s) as recognised by some of the Crohn's disease sera in mice injected with ulcerative colitis tissue filtrate is similar to the antigen(s) detected by Crohn's disease sera in mice injected with Crohn's disease tissue filtrates.

In vitro immunoglobulin synthesis by isolated intestinal mononuclear cells of macroscopically normal mucosa from patients with Crohn's disease has been studied and results compared with those obtained with cells from normal mucosa of resection specimens from patients with colonic carcinoma, or other intestinal disorders. The total lamina propria mononuclear cells (LPMC) in Crohn's disease produced spontaneously less IgA and more IgG than the control groups, but no difference was observed for IgM. An enriched lymphocyte fraction (LPL) of the Crohn's disease patients showed a higher spontaneous synthesis of IgA and IgG when compared with controls. In contrast, another fraction enriched for macrophages (LPM) produced spontaneously less IgA, IgG, and IgM in Crohn's, than in control patients. Incubation with pokeweed mitogen (PWM) decreased immunoglobulin synthesis by LPMC in Crohn's disease and controls, and this was enhanced by simultaneous incubation with concanavalin A. In controls PWM stimulation increased immunoglobulin synthesis by LPL and decreased immunoglobulin synthesis by LPM. In Crohn's disease, however, PWM had no effect on either fraction. This study shows major differences in the regulation of the immunoglobulin synthesis by intestinal cells between Crohn's disease and controls.

Since oral lesions appear to occur more commonly in patients with Crohn's disease (CD) than in normal controls or patients with ulcerative colitis, it has been suggested that a deficit of locally produced IgA allows the invasion of the oral mucous membrane by antigens and contributes to the production of oral lesions. In connection with this hypothesis, the concentrations of IgA, IgM, and IgG in whole and parotid saliva were investigated by the ELISA technique in 20 patients with CD and 20 healthy subjects matched for dental status. IgA predominated in whole and parotid saliva in both patients and controls, and in both groups whole saliva had higher levels of IgA, IgM, and IgG than parotid saliva did. Compared with the controls, IgA, IgM, and IgG levels were significantly elevated in the whole saliva of CD patients. However, no correlation was found between immunoglobulin levels and age, sex, therapy, duration, localization, or activity of the disease.

A group of 310 unrelated patients suffering from Crohn's disease has been screened for quantitative and electrophoretic variations of alpha 1-antitrypsin (alpha 1AT). A comparison was made betweeen patients and healthy controls. The distribution of electrophoretic alpha 1AT variants in the patients showed no significant deviation from the controls. The alpha 1AT quantities are significantly higher in the Crohn's disease population than in the controls.

Polymorphonuclear leucocytes of patients with untreated Crohn's disease showed a lower level of oxidative metabolism than polymorphonuclear leucocytes of treated Crohn's disease patients and controls. Whereas the production of superoxide anion (O-.2) in Crohn's disease patients was almost normal, polymorphonuclear leucocytes of untreated Crohn's disease patients showed a significantly deficient production of hydrogen peroxide (H2O2). In the medically treated Crohn's disease patients, a significant negative correlation was found between H2O2 production by polymorphonuclear leucocytes and disease activity. These findings suggest an intrinsic cellular defect in the neutrophils of Crohn's disease patients which, together with the decreased locomotor function of these cells in vivo, might contribute to the pathogenesis of the chronic inflammation and granuloma formation in this disease.

In a series of 226 patients with Crohn's disease admitted to the University Hospital at Leiden between 1934 and 1972, 21 of the 60 patients with almost total colonic involvement were treated by an ileo-rectal anastomosis between 1957 and 1973. Sixteen patients underwent a proctocolectomy between 1948 and 1972. Five of them have previously had an ileo-rectal anastomosis and are therefore included in both groups. The patients have been followed up for a mean period of 8.3 years. There was no surgical mortality in the group of ileo-rectal anastomosis, whereas in the group of proctocolectomy there have been one early and one late postoperative death. The recurrence rate after ileo-rectal anastomosis was 75 per cent, but 40 per cent of these cases responded well to conservative treatment and have not required further surgery. The recurrence rate after proctocolectomy was 31 per cent. The results concerning mortality, morbidity, and recurrence are compared with the series in the literature.

Features of the neutrophil oxidative metabolism and enzyme activity in peripheral blood neutrophils were studied in 43 patients with Crohn's disease, 13 with ulcerative colitis and 33 healthy controls. The production of superoxide anion (O2-.) by phorbol-myristate-acetate stimulated neutrophils from patients with Crohn's disease and ulcerative colitis was significantly diminished compared with controls mean (SE) = 47.1 (3.6) and 38.0 (3.8) v 67.4 (7.5) nmol/10(7) cells/min, p less than or equal to 0.02, respectively, while the production of hydrogen peroxide was normal. The neutrophil content of superoxide dismutase (SOD), a cytoprotective enzyme, was also markedly diminished in Crohn's disease mean (SE) = 7.11 (0.23) ng SOD/micrograms DNA, p less than 0.05, and ulcerative colitis mean (SE) = 5.74 (0.42) compared with controls 7.84 (0.27), p less than 0.001. In contrast, the concentration of neutrophil elastase, a neutral protease, was found to be normal when compared with neutrophils from controls. The neutrophil O2-. production and the SOD concentrations were significantly and negatively correlated with the disease activity in Crohn's disease and ulcerative colitis. The results indicate diminished neutrophil function in peripheral blood of patients with Crohn's disease and ulcerative colitis as illustrated by a diminished oxidative system, which correlates with the disease activity.

Since abnormal concentrations of immunoglobulins have previously been found in saliva of patients with Crohn's disease, we measured the concentrations of IgA, IgM, and IgG in whole and parotid saliva with the ELISA technique in 20 patients with ulcerative colitis (UC) and 19 healthy control subjects. IgA predominated in whole and parotid saliva in both patients and controls, and in both groups whole saliva had higher levels of IgA, IgM, and IgG than did parotid saliva. IgA and IgG levels were significantly (p less than 0.05) elevated in the whole saliva of UC patients as compared with the controls. IgM was also increased, but the difference did not reach statistical significance. No correlation was found between immunoglobulin levels and age, sex, duration of the disease, and extent of colitis. A significant negative correlation was found between the activity of the disease and the concentration of IgA in whole saliva. The present study therefore suggests that the previously reported abnormalities in the saliva of patients with Crohn's disease and presented as possible evidence for a disease affecting the whole of the gastrointestinal tract, are not specific, since similar findings are observed in UC.

An association between Crohn's disease and immunoglobulin allotypes has been reported. Confirmation of this association in other populations would be of particular importance for the study of hereditary factors in Crohn's disease. In the present study we have typed 155 unrelated Dutch patients with Crohn's disease and 450 blood donors for the Gm, Am, and Km markers. No significant differences were found in Gm phenotypes and haplotypes between patients and controls. It therefore seems unlikely that the immunoglobulin allotypes play an important role in the susceptibility of individuals to Crohn's disease.

Plasminogen activators were determined in intestinal tissue, obtained after surgery from patients with Crohn's disease and ulcerative colitis, and compared with normal intestinal tissue from colorectal cancer patients. The activity and quantity of tissue-plasminogen activator (t-PA) was found to decrease with the severity of inflammation in the patients with inflammatory bowel disease. Urokinase (u-PA) activity, however, was not changed compared with controls or in relation with severity of inflammation. In contrast, the level of u-PA antigen was found to be increased significantly in the inflammatory bowel disease tissues and was also related with severity of inflammation. The difference between u-PA activity and antigen in inflammatory bowel disease tissue could be attributed to an increase in inactive pro-u-PA and u-PA-inhibitor complexes. This increase in u-PA and the concomitant decrease in t-PA, are similar to those found in premalignant colonic adenomas, and might be related to the known increased cancer risk in inflammatory bowel disease.

It is now well established that Crohn’s disease [CD] occurs significantly more frequently in the relatives of the patients than in the general population (1). More over, several families have been reported with more than one sibling affected with CD, and the majority of the affected monozygous twins so far reported are concordant for the disease (2). Ankylosing spondylitis, a disease with a well known genetic background was found to be associated with CD more than was expected by chance alone (2). All these arguments suggest a genetic predisposition for CD. Parameters to define susceptibility should bring an enormous advance in understanding familial CD. Therefore, we started a systematic search for genetic markers in CD.

An epidemiologic study of inflammatory bowel disease was conducted in Regio Leiden, the Netherlands, between 1979 and 1983. Archives of endoscopy, radiology, pathology, and specialist letters were reviewed for suspected patients with inflammatory bowel disease, together with a survey of all general practitioners to verify completeness of data. One thousand forty patients were identified and each diagnosis was reviewed. Two hundred ten patients had Crohn's disease and 257 had ulcerative colitis. Of the other 573 patients, the largest proportion (21%) had incomplete data for disease classification. Others had irritable bowel syndrome, diverticulitis, or ischemic or irradiation colitis; some were nonresident patients with inflammatory bowel disease treated within the region and others were out of the period for inclusion in this investigation. The incidence of Crohn's disease was 3.9 per 10(5) per year and the period prevalence was 48 per 10(5). The sex-specific incidence was similar, although the disease was significantly more common in women aged 20-29 yr. The prevalence in the city municipalities of Leiden and Alphen on the Rijn (63 per 10(5)) was similar but significantly greater than in suburban (39 per 10(5)) or agarian areas (40 per 10(5)). This may be partially due to urban density but not to differences in water supply. The lack of cases in the migrant population almost reaches significant levels, but studies in locations with a higher migrant population may clarify the issue.

The aetiology of Crohn’s disease remains unknown. It has been suggested that genetic predisposition, environmental factors and immunological abnormalities play a role in the pathogenesis of the disease.

In a previous study using total mononuclear cells and lymphocytes, enriched by elutriation centrifugation, of patients with Crohn's disease and ulcerative colitis were found to have a decreased NK cell activity. In the present study the relation with disease activity and treatment, and the effect of recombinant gamma-interferon (gamma-IFN) on NK cell and monocyte cytotoxicity has been studied in 19 patients with Crohn's disease, 11 with ulcerative colitis, two with indeterminate colitis and 12 healthy controls. Patients with active Crohn's disease and active ulcerative colitis were shown to have an impaired NK cell activity compared to the control group. However, no difference was found in the percentage of CD16 (Leu 11+) cells, as determined by fluorocytometry, between patients with active or inactive disease. Moreover, the NK cell impairment was not related to corticosteroid treatment. Recombinant gamma-interferon (gamma-IFN) stimulated significantly the cytotoxic activity of the total mononuclear cells and the monocyte-enriched fraction against all target cell lines, both in patients and controls. No relation was found between the increase in cytotoxicity by gamma-IFN and disease activity in the patients. Stimulation with gamma-IFN demonstrated that the monocyte cytotoxic response of inflammatory bowel disease patients is normal. The present study reveals that the impairment in NK cell activity in patients with inflammatory bowel disease is related to disease activity and therefore suggests to be secondary to the inflammatory process.

Previous optimistic reports led us to undertake a study to determine the value of 99Tcm-sucralphate scintigraphy in the assessment of localization and extent of active inflammatory bowel disease. Eight patients were studied; four had Crohn's disease (three small bowel and one colon localization) and four patients had ulcerative colitis. The results obtained by scintigraphy were compared with those obtained by diagnostic radiology and/or endoscopy. In five patients indium-111 granulocyte scintigraphy was also performed. 99Tcm-sucralphate scans showed total discrepancy with standard investigations in four patients and partial discrepancy in the other four. Furthermore, it was difficult from the images to decide whether the radiolabelled sucralphate indicated true inflammation or normal distribution of the radiopharmaceutical. Patient acceptability was very low due to frequent scanning times and the recommended purgation which was not well tolerated and is contraindicated in severely ill patients. We conclude that this technique is not a good screening test for diagnosing inflammatory bowel disease and we have, therefore, discontinued the study.

A detailed family history of first-degree relatives of 400 unrelated Dutch patients with Crohn's disease revealed a second case among first-degree relatives in 32 families (8%). The most frequently observed positive relationship was among siblings. In two families, three children had Crohn's disease. One pair of concordant monozygotic twins was found; in the other pair of monozygotic twins, only one was affected by the disease. None of the five dizygotic twin pairs was found to be concordant for Crohn's disease. The results of the present study, together with those published in the medical literature, support a hereditary predisposition for Crohn's disease.