Incidence and clinical significance of lactose malabsorption in ulcerative colitis and Crohn's disease

The incidence of lactose malabsorption was investigated in 85 patients with ulcerative colitis and 71 patients with Crohn's disease by means of lactose tolerance tests and disaccharidase determinations in small intestinal mucosa. Eight patients with ulcerative colitis (9%) and four with Crohn's disease (6%) had lactose malabsorption. A control group displayed a similar incidence. It is concluded that lactose malabsorption is not particularly common in ulcerative colitis and Crohn's disease. If it is present, its aetiology seems to be unrelated to the intestinal disease.Transitional lactose malabsorption was detected in two cases during a relapse of ulcerative colitis.Institution of a lactose-free (or lactose-poor) diet was an important supporting measure in seven patients who were unaware of their milk intolerance, in particular in two with ileostomy. Therefore, it is recommended that a lactose tolerance test should always be performed in patients with ulcerative colitis or Crohn's disease.Twenty-one patients with ulcerative colitis and nine with Crohn's disease, none of whom had lactose malabsorption, were placed on milk-free diets. A beneficial effect was noticed in five of the patients with ulcerative colitis, and in three of those with Crohn's disease. The mechanism is unknown.Evidence is presented that milk allergy is not responsible for the beneficial effect of a lactosefree diet in patients with associated lactose malabsorption.     

P-ANCA in monozygotic twins with inflammatory bowel disease.

Perinuclear antineutrophil cytoplasmic antibodies (P-ANCA) have been demonstrated in patients with ulcerative colitis and in a higher frequency than expected in their first degree relatives. A hypothesis was proposed that P-ANCA is genetically determined and may represent a subclinical marker of genetic susceptibility to ulcerative colitis. This study analysed P-ANCA in monozygotic twins with inflammatory bowel disease to evaluate this hypothesis further. P-ANCA was analysed with indirect immunofluorescence technique in 12 monozygotic twin pairs with ulcerative colitis and 14 twin pairs with Crohn's disease. Furthermore, the study included 21 non-twin patients with ulcerative colitis, 18 non-twin patients with Crohn's disease, and 52 healthy controls matched for sex and age. In ulcerative colitis P-ANCA occurred in nine of 14 (64.3%) monozygotic twins and in 13 of 21 (61.9%) non-twin cases, which was significantly different compared with healthy controls who were positive in three of 52 (5.8%) cases (p < 0.0001). P-ANCA was found in two of 10 (20%) healthy twin siblings to twins with ulcerative colitis, which was not significantly different from healthy controls (p = 0.18). The results in Crohn's disease did not differ from healthy controls. Previous findings of P-ANCA occurring in ulcerative colitis but not in Crohn's disease are supported. This study does not support the hypothesis that P-ANCA is a subclinical marker of genetic susceptibility to ulcerative colitis.     

Crohn's disease and ulcerative colitis in the same patient.

A well documented case of a patient with both Crohn's disease and ulcerative colitis is presented. A 29 year old woman underwent resection of her terminal ileum and ascending colon for typical Crohn's disease with ileocolitis. Eleven years later, an ileoproctocolectomy was performed for typical ulcerative colitis involving the left colon. The resection specimen also showed evidence of colonic Crohn's disease near the anastomotic site. This unusual case shows that Crohn's disease and ulcerative colitis can occur in the same patient. The rarity of such cases supports the concept that Crohn's disease and ulcerative colitis are separate entities, rather than different manifestations of the same disease process.     

Effect of infliximab in the treatment of refractory inflammatory bowel disease with complication]

BACKGROUND/AIMS: Many studies on infliximab have confirmed its efficacy in the remission induction and even maintenance in refractory and fistulizing Crohn's disease. We report the treatment efficacy of infliximab in Crohn's disease and ulcerative colitis refractory to steroid treatment and the complications of infliximab treatment. METHODS: We performed infliximab administration in 5 cases (3 Crohn's disease, 2 ulcerative colitis) refractory to systemic steroid treatment and 5 cases of Crohn's disease with fistula. Patients received an intravenous infusion of infliximab at 3-5 mg/kg body weight. RESULTS: In 3 cases of refractory Crohn's patients, clinical response and remission induction were obtained in 2 (67%) and 1 cases (33%). After infusion of infliximab, the occlusion of internal fistula could be found in all 2 cases. Two out of 3 cases of anal fistula were completely healed. In two cases of refractory ulcerative colitis, one case who showed clinical manifestation of toxic megacolon had improved and avoided the colectomy, but the other case did not respond to the infusion of infliximab and underwent colon resection. CONCLUSIONS: We found that administration of infliximab is an effective alternative for refractory and fistulizing Crohn's disease but further studies are necessary for refractory ulcerative colitis.     

Prevalence and family risk of ulcerative colitis and Crohn's disease: an epidemiological study among Europeans and south Asians in Leicestershire.

The family history of patients identified during incidence studies in Leicestershire were investigated and the prevalence and comparative risks calculated; 1254 patients aged 15 to 80 years were sent a questionnaire about their family history. All cases with a positive family history were reviewed and confirmed cases included in the study. In Europeans the standardised prevalence of Crohn's disease was 75.8/10(5) and that of ulcerative colitis 90.8/10(5). The prevalence of Crohn's disease among South Asians was 33.2/10(5) and that of ulcerative colitis 135/10(5). The prevalence of Crohn's disease in Europeans was significantly greater than that in Hindus (chi 2 = 16, p < 0.001), while the prevalence of ulcerative colitis was significantly lower in Europeans than Hindus (chi 2 = 27, p < 0.001) and Sikhs (chi 2 = 4.4, p < 0.05). The comparative risk of developing ulcerative colitis in first degree relatives of Europeans patients with ulcerative colitis was increased by approximately 15, but the risk of Crohn's disease was not increased. The comparative risk of developing Crohn's disease among first degree relatives of patients with Crohn's disease was increased by up to 35, the comparative risk of ulcerative colitis was approximately 3. The risk among relatives of South Asian patients with Crohn's disease was not increased, but the risk of ulcerative colitis to relatives of patients with ulcerative colitis was. This study supports the view that Crohn's disease and ulcerative colitis arise in people with a genetic predisposition and exposed to some, as yet unknown, environmental factor.     

Microaggregate of immunostained macrophages in noninflamed gastroduodenal mucosa: a new useful histological marker for differentiating Crohn's colitis from ulcerative colitis

OBJECTIVE: In 10% of cases it may be difficult to differentiate Crohn's colitis from ulcerative colitis. Distinguishing the two conditions is important because they are distinct entities with different therapeutic implications. Noncaseating granulomas are usually considered diagnostic of Crohn's disease. We previously reported that the presence of a microaggregate of immunostained macrophages within the noninflamed gastroduodenal mucosa was a characteristic finding of Crohn's disease. The aim of this study was to determine whether a microaggregate of immunostained macrophages can be a reliable marker for differentiating Crohn's colitis from ulcerative colitis. METHODS: We investigated the presence of microaggregates of immunostained macrophages and epithelioid cell granulomas in biopsy specimens taken from the noninflamed gastroduodenal mucosa of 22 known Crohn's colitis patients and 23 established ulcerative colitis patients. The incidence of microaggregates and granulomas was compared between these two groups. RESULTS: Microaggregates and granulomas were detected only in the Crohn's colitis patients. In addition, the presence of microaggregates was more frequent than that of granulomas in Crohn's colitis patients (54.5% and 18.2%, respectively, 95% confidence interval for the difference: 10.0-62.7%). CONCLUSION: Detecting a microaggregate of immunostained macrophages in a biopsy specimen taken from noninflamed gastroduodenal mucosa seems to be a useful method for differentiating Crohn's colitis from ulcerative colitis.     

Inflammatory bowel disease and leukemia

In a review of a large number of patients with inflammatory bowel disease, leukemia was observed in five patients with chronic ulcerative colitis and in two patients with Crohn's disease. In ulcerative colitis patients, there were three cases of acute myelocytic leukemia and one case each of acute lymphoblastic leukemia and chronic granulocytic leukemia. In Crohn's disease patients, there was one case each of chronic granulocytic leukemia and chronic lymphocytic leukemia associated with thrombocythemia. Sixteen other cases of leukemia have been reported to date in inflammatory bowel disease. All types of leukemia, but particularly acute myelocytic leukemia, have been described. There has been no single common feature as to type (whether ulcerative colitis or Crohn's disease), extent and course, or medical and surgical treatment of the bowel disease. The relative risk of leukemia in patients with ulcerative colitis was 5.3 [95% confidence interval 1.7 to 12.3 (P<0.01)] and of acute myelocytic leukemia 11.4 [95% confidence interval 2.3 to 24.9 (P<0.01)]. Our data on patients with Crohn's disease were not sufficient to assess the statistical significance of leukemia in this disease. This study suggests that there may be an increased risk of leukemia, particularly acute myelocytic leukemia, in ulcerative colitis. The causal relationship, if any, remains undetermined.     

The prognosis of inflammatory bowel disease

The complications of ulcerative colitis generally develop during the first two years of disease. The mortality is higher than expected and the highest likelihood of colectomy also occurs early in the disease. Mortality in Crohn's disease is greater than expected, especially in males. For both conditions, the overall mortality has decreased steadily, and currently is less than 5%. Ulcerative colitis is curable with proctocolectomy and ileostomy. In Crohn's disease, intestinal resection and reanastomosis is followed by recurrence in the majority of patients. The recurrence rate after proctocolectomy and ileostomy for Crohn's disease of the colon also is considerable, ranging from 20% to 35%. In ulcerative colitis, the more colon involved, the more frequent and more serious are the complications. In Crohn's disease, the anatomic pattern of disease tends to predict the type and extent of complications. Both ulcerative colitis and Crohn's disease appear to follow a more severe course in children and adolescents with "inflammatory bowel disease." Patients with either ulcerative colitis or Crohn's disease are at increased risk for the later development of cancer. In ulcerative colitis, the excess risk is limited to colorectal cancer. Patients with Crohn's disease have increased cancer rates for both the small and large bowel. Finally, most patients with these diseases are able to maintain normal occupations and enjoy reasonably stable social and economic situations. The successful adaptation of patients with inflammatory bowel disease is influenced by a hopeful, optimistic personality and by an encouraging, supportive physician.     

Concanavalin A-binding cholesterol crystallization inhibiting and promoting activity in bile from patients with Crohn's disease compared to patients with ulcerative colitis.

BACKGROUND/AIMS: Crohn's disease is a risk factor for gallstone formation. In contrast, patients with ulcerative colitis have an incidence of gallstone formation comparable to the general population. The reason for this difference is not known. The aim of this study was to elucidate the factors controlling cholesterol crystallization in gallbladder bile of Crohn's disease and ulcerative colitis patients. METHODS: Gallbladder bile was obtained by aspiration during bowel resections (26 Crohn's disease patients, 20 ulcerative colitis patients). Biliary lipid composition, crystal detection time and the effect of extraction of the concanavalin A-binding fraction on crystal formation were determined. RESULTS: Cholesterol crystals were present in seven of the 26 bile samples of Crohn's disease-patients and one of the 20 ulcerative colitis patients. Four of the bile samples of Crohn's disease patients were fast nucleating. None of the 20 ulcerative colitis patients had fast nucleating bile. Lipid composition, total lipid concentration and CSI were not significantly different between the two groups. In Crohn's disease patients extraction of concanavalin A-binding fraction decreased crystallization in 10 bile samples but accelerated crystallization in one bile sample. In eight bile samples from ulcerative colitis patients crystallization increased after concanavalin A-binding fraction extraction. CONCLUSIONS: Compared to ulcerative colitis patients, gallbladder bile of Crohn's disease patients showed increased cholesterol crystallization despite comparable lipid composition and cholesterol saturation index. This difference is caused by increased cholesterol crystallization-promoting activity. Bile from ulcerative colitis patients contains a Con A-binding factor which inhibits cholesterol crystallization.     

High circulating concentrations of interleukin-6 in active Crohn''s disease but not ulcerative colitis.

Peripheral venous plasma concentrations of interleukin-6 were studied in 21 patients with active Crohn's disease, 20 patients with ulcerative colitis, and 16 control subjects. Interleukin-6 was detected in the plasma of 18 of 21 patients with Crohn's disease (median 47 (range less than 20-250) pg/ml) but in only two with ulcerative colitis and two control subjects. In the patients with Crohn's disease there was a significant negative correlation between the plasma interleukin-6 and the serum albumin concentrations. In eight patients with Crohn's disease and five patients with ulcerative colitis undergoing resection plasma from peripheral circulation and mesenteric vein draining diseased intestine was studied. Interleukin-6 was detected in seven of eight peripheral and mesenteric samples from the patients with Crohn's disease but was not detected in any of the samples from the patients with ulcerative colitis. There was no significant difference between mesenteric and peripheral samples in the concentrations of interleukin-6.     

Microsatellite Instability Is Uncommon in Intestinal Mucosa of Patients with Crohn's Disease

Patients with long-standing inflammatory bowel disease have an increased risk for colorectal carcinoma. Microsatellite instability occurs in colonic neoplasms and has been reported in colonic tissues from patients with ulcerative colitis. Patients with Crohn's disease also have an increased risk for colorectal cancer, although it is lower than that associated with ulcerative colitis. This study was designed to determine whether microsatellite instability occurs in Crohn's disease, and whether it occurs with similar frequency to that observed in ulcerative colitis. In all, 177 tissue samples from 33 patients with Crohn's disease were evaluated for microsatellite alterations. Microsatellite instability occurred in five different tissue samples from one of 33 Crohn's disease patients. Four of the five tissue samples showed microsatellite instability at more than one locus. We conclude that microsatellite instability is less common in Crohn's disease than ulcerative colitis and may reflect differences in cancer risk between these two forms of inflammatory bowel disease.     

RDW as an Additional Marker in Inflammatory Bowel Disease/Undifferentiated Colitis

BACKGROUND: Anemia is a common complication in inflammatory bowel disease patients. We postulate that the distribution of lesions in Crohn's disease is more likely than ulcerative colitis to lead to malabsorption as an additional cause of anemia. RDW, a simple and inexpensive test could be an additional differentiating test. METHODS AND RESULTS: Retrospective review of 284 cases of which 156 cases were diagnosed with Crohn's disease and 128 cases were diagnosed with ulcerative colitis. There was a significant difference in the mean RDW between the Crohn's and the ulcerative colitis cases (14.9 vs. 14.3, P = .027). CONCLUSIONS: We conclude there is a statistical significance between the two groups though this may not represent a clinically significant difference. From our analysis we conclude that RDW is statistically significant and with the implementation of a more rigorous study design and analysis of further data RDW may prove to be a clinically effective marker in differentiating Crohn's disease from ulcerative colitis.     

Compared azathioprine efficacy in ulcerative colitis and in Crohn's disease

AIM: To compare the 6-month efficacy and tolerance of azathioprine in 68 patients with steroid-resistant or steroid-dependent chronic ulcerative colitis (n=30) or Crohn's disease (n=38).METHODS: Clinical remission was defined as a Crohn's Disease Activity Index<150 for Crohn's disease and number of non-bloody stools<=3/day for ulcerative colitis, associated with prednisone requirement<=10 mg/day.RESULTS: Seventy-three per cent of patients with ulcerative colitis had distal or left-sided colitis and 84% of patients with Crohn's disease had pancolitis. Azathioprine was discontinued early for side-effect in 8 (26.7%) patients with ulcerative colitis and in 8 (21.1%) patients with Crohn's disease (NS). In patients treated at least 6 months by azathioprine, clinical remission rates were 77.3% and 70% for chronic ulcerative colitis and Crohn's disease (NS). Complete corticosteroids weaning was obtained significantly more often in ulcerative colitis patients than in Crohn's disease patients (59.1% vs 30%; P<0.05).CONCLUSION: Azathioprine seems to be at least as effective and equally tolerated in steroid-resistant or steroid-dependent chronic ulcerative colitis or Crohn's disease patients.     

Nodular duodenitis involving CD8+ cell infiltration in patients with ulcerative colitis

BACKGROUND/AIMS: Limited efforts have been made to determine changes in the upper gastrointestinal tract in ulcerative colitis. The aim of this study was to analyze gastroduodenal lesions in patients with ulcerative colitis. METHODOLOGY: The endoscopical appearance of lesions in the duodenum and stomach was first examined. Biopsy specimens taken from 25 patients with ulcerative colitis, as well as 21 with Crohn's disease and 16 with nonspecific gastroduodenitis who had no Helicobacter pylori infection, were then evaluated by histology and immunohistochemistry for CD8, CD68 and HLA-DR. In ulcerative colitis patients, the HLA-phenotype was also analyzed by the standard NIH complement-dependent microlymphocyte toxicity assay. RESULTS: Endoscopically evident alteration of nodularity in the descending part of duodenum was prominent in ulcerative colitis and Crohn's disease, but not gastroduodenitis. Histological inflammatory change of the duodenal bulb in ulcerative colitis and Crohn's disease was mild as compared to gastroduodenitis cases. Endoscopic and histological change (redness and deformity of villi) in the duodenum were more prominent in ulcerative colitis patients with pancolitis than those with left-sided/proctitis. CD8+ cells infiltrating both the duodenum and stomach were increased in ulcerative colitis and Crohn's disease as compared to gastroduodenitis whereas focal perifoveolar accumulation of CD68+ cells and enhanced epithelial expression of HLA-DR were characteristic of Crohn's disease. Histopathological alteration in the duodenum was particularly prevalent in ulcerative colitis patients with HLA-DR4 and Cw1. CONCLUSIONS: Nodular, histologically mild duodenitis involving CD8+ cell infiltration, the severity of which positively correlates with the extent of colitis, is characteristic of ulcerative colitis.     

Fulminant colitis in inflammatory bowel disease

PURPOSE: The morphologic features of fulminant colitis may be nonspecific, making differentiation between ulcerative colitis and Crohn's disease difficult, even after colectomy. The aims of this study were 1) to identify histologic features that accurately differentiated ulcerative colitis, Crohn's disease, and indeterminate colitis in fulminant colectomy specimens; 2) to determine how frequently subsequent clinical course altered the pathologic diagnosis; and 3) to evaluate the natural history of histologically diagnosed indeterminate colitis. METHODS: Ninety-five fulminant colectomy specimens were evaluated, of which 85 had an original diagnosis of fulminant inflammatory bowel disease. Complete pathologic material and comprehensive clinical follow-up information was available on 67 cases of inflammatory bowel disease. These were re-evaluated in a blinded fashion, and histopathologic features were compared with the original diagnosis and reviewed in the light of subsequent clinical behavior to reach a final diagnosis. RESULTS: Evaluation of macroscopic features was not helpful in differentiating ulcerative colitis from Crohn's disease. Microscopic examination correctly diagnosed ulcerative colitis or Crohn's disease in only 58 of 67 (87 percent) cases. A further three cases (4 percent) were definitively classified after correlation with clinical data, leaving a residual six cases that were diagnosed as indeterminate colitis. Granulomas and lymphoid aggregates were the two most specific indicators of Crohn's disease. CONCLUSIONS: Histopathologic evaluation alone has limitations in the accurate classification of fulminant inflammatory bowel disease. Histologically diagnosed indeterminate colitis is a heterogeneous group that may include some patients who subsequently prove to have ulcerative colitis or Crohn's disease.Presented at the meeting of the United States and Canadian Academy of Pathology, Orlando, Florida, March 1 to 7, 1997.     

Cytokine production in patients with inflammatory bowel disease.

The production of cytokines in peripheral blood mononuclear leukocytes of patients with inflammatory bowel disease was investigated. T cell subset analysis and differential white blood cell counts were also performed. Thirty five patients with ulcerative colitis, 14 with Crohn's disease, and 15 age matched healthy volunteers were studied. No differences were observed in T cell subsets and OKT4/OKT8 ratios in patients with ulcerative colitis or Crohn's disease compared with controls. Interleukin 1 beta production was significantly increased in active ulcerative colitis and Crohn's disease, compared with values in controls, but returned to control levels in the inactive stages. In addition, in active ulcerative colitis and Crohn's disease, there were significant correlations between the interleukin 1 beta production and the ulcerative colitis activity index or Crohn's disease activity index. Interleukin 2 production was also significantly increased in the active ulcerative colitis and significantly correlated to the activity index, but there was no change in Crohn's disease patients compared with controls. Gamma interferon production in patients was the same as that in controls. This study suggests that the interleukin 1 beta and 2 values in peripheral mononuclear leukocytes of active untreated inflammatory bowel disease are indicators of the disease states of ulcerative colitis or Crohn's disease, or both.     

Evolutionary changes in the pathologic diagnosis after the ileoanal pouch procedure

PURPOSE: Inadequate initial differentiation between ulcerative colitis and Crohn's disease may lead to a diagnosis of indeterminate colitis. Construction of an ileoanal pouch in these patients may result in significant morbidity and pouch failure when the ultimate diagnosis is Crohn's disease. METHOD: We prospectively studied 543 patients with idiopathic inflammatory bowel disease to determine whether a patient's pathologic diagnosis changed with time and how it affected outcome. RESULTS: Preoperative diagnosis was ulcerative colitis in 499 patients, indeterminate colitis in 42 patients, and Crohn's disease in 2 patients. Prior colectomy was performed in 58 percent of patients with ulcerative colitis and in all patients with indeterminate colitis and Crohn's disease. Postoperatively, the diagnosis changed in 20 patients with ulcerative colitis (13 to indeterminate colitis, 7 to Crohn's disease). Another two patients with indeterminate colitis showed evidence of Crohn's disease in the resected rectal specimen. As patients were followed up, an additional 13 patients were found to have Crohn's disease (5 indeterminate colitis, 8 ulcerative colitis). With the current diagnosis, perineal complications and pouch failure occurred, respectively, in 23 and in 2 percent of patients with ulcerative colitis, in 44 and in 12 percent of patients with indeterminate colitis, and in 63 and in 37 percent of patients with Crohn's disease. Pathologic diagnosis was altered in 35 patients (6 percent) overall, with a 12-fold increase in the diagnosis of Crohn's disease. Only 3 percent of patients with ulcerative colitis compared with 13 percent of patients with indeterminate colitis had a change in diagnosis to Crohn's disease (P =0.006; Fisher's exact test). CONCLUSION: Pouch-related complications, eventual pouch failure, and discovery of underlying Crohn's disease occurred in a significant number of patients with a diagnosis of indeterminate colitis. Until more accurate diagnostic differentiation is available, caution is advised in recommending the ileoanal pouch procedure to patients with indeterminate colitis.Read at the meeting of The American Society of Colon and Rectal Surgeons, Seattle, Washington, June 9 to 14, 1996.     

Clinical Characteristics and Natural History of Colitis in the Elderly

The clinical behavior and course of Ischemic, ulcerative, and Crohn's colitis in the elderly are analyzed. Fifty-two patients with ischemic colitis, 11 with ulcerative colitis, and four with Crohn's colitis composed the study group. Patients with ischemic colitis were older and had a higher incidence of arteriosclerotic cardiovascular disease than those with inflammatory bowel disease. A potentially obstructing colonic lesion was present in 12% of those with ischemic colitis. Spontaneous rapid resolution occurred in 42% of those with ischemic colitis, but in no patient with ulcerative or Crohn's colitis. Of the 31 remaining patients with Ischemic colitis, 20% bad recurrent disease and 80% required operation. Almost 10% of patients with ischemic colitis died postoperatively. Of those patients with ulcerative colitis, two developed toxic dilitation, three required operation, and three died on the first admission. All patients with Crohn's colitis required operation. The prognosis for colitis in elderly patients, regardless of type, is worse than in young patients.     

Immunoglobulin G (IgG), IgG1, and IgG2 determinations from endoscopic biopsy specimens in control, Crohn's disease, and ulcerative colitis subjects.

Acute exacerbations of chronic inflammatory bowel disease (ulcerative colitis and Crohn's disease) are characterised by an increase in immunoglobulin G (IgG) positive cells in the mucosa, whereas uninflamed mucosa of inflammatory bowel disease patients displays only moderately increased or normal numbers of these cells. Previous data suggest that acute exacerbations of ulcerative colitis and Crohn's disease can be distinguished by different IgG subclass expression of mucosal immunocytes and a different IgG subclass production pattern of lamina propria lymphocytes. A procedure to obtain enough intestinal mononuclear cells from biopsy specimens to measure in vitro IgG and IgG1 production in control subjects and various patient groups has been established. IgG2 could be measured in Crohn's disease and ulcerative colitis only, as the concentrations in control subjects were below the sensitivity of the ELISA method. We found that IgG and IgG1 production correlated with the degree of local inflammation in both diseases, even in slightly inflamed mucosa, compared with control subjects. The proportion of IgG1 subclass was significantly increased in severely inflamed mucosa of both ulcerative colitis and Crohn's disease patients. A major difference between Crohn's disease and ulcerative colitis mucosa is apparent in mild or no inflammation. In Crohn's disease mucosa in remission, the IgG1/IgG ratio is comparable with that in controls, yet ulcerative colitis mucosa still displays significantly increased proportions of IgG1. In addition, the IgG2/IgG ratio is 0.12 in ulcerative colitis and 0.19 in Crohn's disease patients. The results show the dependence of local IgG and IgG1 production on the degree of inflammation and that an increase in subclass IgG1 in ulcerative colitis is present at all stages, including remission. These findings support the hypothesis that different immunoregulatory mechanisms are involved in Crohn's disease and ulcerative colitis. Environmental stimuli or genetic background may be responsible for the observed differences.