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Background/aims: Intrahepatic cholestasis of pregnancy is a rare disease of unknown etiology, with a strikingly higher prevalence in Chile than in most other countries. Although several studies suggest that a genetic predisposition is involved in the pathogenesis, no genetic disease-marker has so far been identified. Using a recently developed HLA-genotyping technique, we performed an association study with a highly polymorphic HLA class II gene in patients with recurrent intrahepatic cholestasis of pregnancy and normal control patients., Methods: Genomic DNA was extracted from 26 unrelated patients with recurrent ICP and 30 unrelated multiparous women without a personal or family history of this disease among a Chilean population. The polymorphic second exon of the HLA-DPB1 gene was amplified by the polymerase chain reaction and hybridized with 25 sequence-specific oligonucleotide probes to assign the HLA-DPB1 alleles on the basis of known sequence variations., Results: Out of more than 50 HLA-DPB1 alleles presently known, 13 were represented in the analyzed groups. Patients with ICP had a higher frequency of the allele DPB*0402 when compared to controls (69% vs 43%). This difference failed to reach statistical significance (x2 = 2.81, corrected p > 0.5). No significant differences were observed between the frequencies of other detected HLA-DPB1 alleles in the analyzed groups., Conclusion: In this study, we observed a high frequency of the allele HLA-DPB1*0402 among Chilean patients with recurrent ICP, but no association of the disease with HLA-DPB1 alleles. Therefore, HLA-DPB1 alleles do not play a major role in determining susceptibility or resistance to intrahepatic cholestasis of pregnancy.

There is a strong genetic influence on the susceptibility to celiac disease. Although in the vast majority of patients with celiac disease, the HLA-DQ(alpha1*0501, beta1*0201) heterodimer encoded by the alleles HLA-DQA1*0501 and HLA-DQB1*0201 seems to confer the primary disease susceptibility, it cannot be excluded that other genes contribute to disease susceptibility, as indicated by the difference in concordance rates between monozygotic twins and HLA identical siblings (70% vs. 30%). Obviously other genes involved in the genetic control of T cell mediated immune response could potentially influence susceptibility to celiac disease. The density of T cells using the gammadelta T cell receptor (TCR) is considerably increased in the jejunal epithelium of patients with celiac disease, an abnormality considered to be specific for celiac disease. This suggests an involvement of gammadelta T cells in the pathogenesis of the disease. To ascertain whether the TCR delta (TCRD) gene contributes to celiac disease susceptibility we carried out an association study and genetic linkage analysis using a highly polymorphic microsatellite marker at the TCRD locus on chromosome 14q11.2. The association study demonstrated no significant difference in allele frequencies of the TCRD gene marker between celiac disease patients and controls; accordingly, the relative risk estimates did not reach the level of statistical significance. In the linkage analysis, performed in 23 families, the logarithm of the odds (LOD) scores calculated for celiac disease versus the TCRD gene marker excluded linkage, suggesting that there is no determinant contributing to celiac disease status at or 5 cM distant to the analyzed TCRD gene marker. In conclusion, the results of the present study provide no evidence that the analyzed TCRD gene contributes substantially to celiac disease susceptibility.

Cytokines serve a central function as key factors in the regulation of the intestinal immune response and mediation of tissue damage in inflammatory bowel disease (IBD). Abnormalities in the expression of immunoregulatory cytokines such as IL-2, IL-4, IL-10 and interferon-gamma (IFN-gamma) may indicate a dysregulation of intestinal immunity probably associated with pathogenic events. Therefore, cytokine mRNA concentrations were determined in the mucosa of patients with IBD at sites of active (n = 13) and inactive (n = 12) ulcerative colitis (UC), active (n = 11) and inactive (n = 11) Crohn's disease (CD) and in control patients (n = 14) using quantitative RT-PCR. IL-10 mRNA concentrations were significantly increased in patients with both active UC (P < 0.001) and active CD (P < 0.005) compared with control patients. IFN-gamma mRNA concentrations were also significantly increased both in patients with active UC (P < 0.02) and active CD (P < 0.05) compared with control patients, whereas IL-2 mRNA levels were significantly (P < 0.02) increased only in active CD. IL-4 mRNA expression in the intestinal mucosa was frequently below the detection limit. Our results demonstrate that chronic intestinal inflammation in patients with CD is characterized by an increase of Th1-like cytokines. Furthermore, the increased IL-10 mRNA expression at sites of active IBD suggests that IL-10 is an important regulatory component involved in the control of the inflammatory response in inflammatory bowel disease.

Although a disturbed immune response to constituents of the gut mucosa has been implicated in the pathogenesis of inflammatory bowel disease, the mechanisms are still unclear. Intestinal T-cells derived from gut biopsies were propagated in vitro as single and co-cultures under different experimental conditions prior to flow cytometry. Intestinal T-cell lines from inflamed mucosa (n = 69) showed a significant (P < 0.001) decrease in CD4+ T-cells compared to T-cells from normal (n = 49) and uninflamed (n = 29) tissue specimens. Co-culturing of inflamed and uninflamed mucosa led to a normalization of CD4+ T-cells in cultures derived from inflamed mucosa. Analysis of supernatants revealed a significantly (P < 0.001) increased secretion of IL-4 under co-culture conditions. Moreover, stimulation of cultures derived from inflamed mucosa with rIL-4 led to a significant (P < 0.001) increase in CD4+ T-cells, whereas anti-IL-4 antibodies or IFN-gamma supplementation of T-cells derived from uninflamed mucosa significantly (P < 0.001) reduced the CD4+ subset. Treatment with IFN-gamma and anti-IL-4 antibodies did not affect the phenotype of T-cells derived from inflamed mucosa. These data suggest that IL-4 might play a key role in the intestinal immune response. Furthermore, this in vitro system allows the investigation of mucosal immune mechanisms in more detail under standardized conditions.

The major histocompatibility complex class II alleles at the HLA-DPB1 locus were investigated in 32 German Caucasoid patients with primary biliary cirrhosis (PBC) and compared with those from 47 normal control patients using molecular genotyping techniques. The second exon of the HLA-DPB1 gene was amplified by polymerase chain reaction (PCR) and hybridized with 25 sequence-specific oligonucleotides (SSOs) to assign the HLA-DPB1 alleles on the basis of known sequence variations, according to the protocols of the Eleventh International Histocompatibility Workshop. A strong association of PBC was found with the allele HLA-DPB1*0301. The allele HLA DPB1*0301 was present in 50% (16 of 32) of the patients with PBC compared with 13% (6 of 47) of normal controls (P corrected < .015), whereas the other HLA-DPB1 alleles showed no significant differences in both groups. The relative risk (RR) estimate for the allele HLA-DPB1*0301 was 6.8 (95% confidence limits: 2.27 to 20.57). In summary, this study clearly demonstrates an association of PBC with the HLA-DPB1*0301 allele in German Caucasoids and may add new data to the immunogenetic background of PBC, suggesting a contribution of the HLA-DPB1 gene to the genetic susceptibility of the disease.

Ascites is most frequently a symptom of advanced chronic liver disease. The pathogenesis of ascites with portal hypertension is complex, and the interaction between liver and kidney is incompletely known. Due to the differing pathogenetic mechanisms and the consecutively different therapeutic approaches, the differential diagnosis of ascites has to be clearly evaluated by measurement of certain laboratory parameters in the ascitic fluid. The prior to therapy basic principles in the therapy of the portal ascites include bed rest, dietary restriction of sodium and water intake, therapeutic paracentesis and diuretics in increasing doses. With this basic therapeutic approach 85 to 90% of the patients can be treated successfully. In patients with complicated forms of ascites or hepatorenal syndrome, other therapeutic strategies have to be used.

Background: Genetic susceptibility of celiac disease is primarily associated with a particular combination of and HLA-DQA1/DQB1 gene; however, this does not fully account for the genetic predisposition. Therefore, the aim of this study was to examine whether T-cell receptor (TCR) genes may be susceptibility genes in celiac disease., Methods: HLA class II typing was performed by polymerase chain reaction amplification in combination with sequence-specific oligonucleotide hybridization. TCR alpha (TCRA), TCR gamma (TCRG), and TCR beta (TCRB) loci were investigated by restriction fragment length polymorphism analysis., Results: Allelic frequencies of TCRA, TCRG, and TCRB variable genes were compared between patients with celiac disease (n = 53) and control patients (n = 67), and relative risk (RR) estimates were calculated. The RR was 1.67 for allele C1 at TCRA1, 3.35 for allele D2 at TCRA2, 1.66 for allele B2 at TCRG, and 1.35 for allele B at TCRB, showing no significant association. Additionally, linkage analysis was performed in 23 families. The logarithm of odd scores for celiac disease vs. the TCR variable genes at TCRA, TCRG, and TCRB showed no significant linkage., Conclusions: These data suggest that the analyzed TCR variable gene segments V alpha 1.2, V gamma 11, and V beta 8 do not play a major role in susceptibility to celiac disease.

The pathogenesis and etiology of inflammatory bowel disease (IBD) is poorly understood. As a matter of fact, it is not even certain whether either one is a single entity with different forms of clinical manifestations, or whether each one represents a single clearly separable entity. Common features of both diseases are chronic persistence, recurrent exacerbation and remission, the production of autoantibodies, as well as the expression of aberrant HLA-class II molecules on the surface of epithelial cells on the site of inflammation gut. It is likely that these events involve a disturbed immunoregulatory function or autoimmune process. Since the beginning of investigation the cause of IBD, infectious agents (bacteria, virus, mycobacterium paratuberculosis and others) or bacterial products (endotoxin, peptidoglycans from the bacterial cell wall) have been considered as primary causes. Epidemiological studies showed a marked increase of the incidence rates of IBD in industrial countries leading to the hypothesis, that environmental factors could play a role in the pathogenesis of the disease. So far it is clear that the major identified risk factor for IBD is a genetic susceptibility confirmed by studies showing a positive family history.

Although most T cells express the alpha/beta TCR, the gamma/delta TCR is expressed only on a small percentage of peripheral lymphocytes and CD3+ intestinal T cells. The most striking feature is a wide variation in the proportion of gamma/delta+ T cells in freshly isolated peripheral blood cells from normal individuals and patients with IBD. The augmentation of the gamma/delta+ T cell subpopulation derived from human intestinal biopsies after repeated stimulation with MT, even in the absence of filler cells, suggests that gamma/delta+ cells from human gut mucosa may play a role in generating a primary immune response to MT.

Each abnormal sonographic finding in the gastrointestinal tract requires further evaluation including other diagnostic means, since differentiation of abdominal diseases is not possible by sonography alone. The pathologic finding of a stomach-cocarde is suspicious for a malignoma. Sonographic control is useful in patients with chronic inflammatory diseases of the intestinal tract, since intestinal as well as extraintestinal complications determining further treatment can be anticipated.

Real time ultrasound findings in 137 patients with proven or suspected liver metastasis and 51 patients with suspected malignant lymphoma were analyzed in order to define the accuracy of this method in tumour staging procedures. Sensitivity of liver metastasis was low (54.4%), while specificity (92.0%) and negative predictive value (95.8%) were good. Sensitivity for malignant lymphoma was better (84.6%), but specificity was less satisfactory (72.0%). Accuracy was dependent of the type of the primary tumour, bronchial carcinoma resulting in a very poor detection of liver metastases and suspected metastatic lymphoma leading to a large number of false positive results. We conclude from our data that only positive ultrasound findings of liver metastases or multiple lymphoma and probably a negative examination of the liver in patients with colonic carcinoma are sufficiently reliable to be used for therapeutic decisions in patients with malignant diseases.

Two patients with complicated acute pancreatitis are demonstrated. Sonographic factors are compared to laboratory and clinical findings. Ultrasound can add relevant information for classification and thereby supply an indication for surgery in patients with acute pancreatitis. This is especially true since laboratory classification of the grade of the disease is as yet not generally accepted.

Erythrocyte and plasma ferritin was followed in 13 patients with iron overload undergoing phlebotomies for at least 6 months in comparison with untreated patients and normal males. Plasma ferritin was widely scattered with an average of only twice the normal, whereas erythrocyte ferritin was highly elevated to about twelve times the normal (p less than 0.0001). - The time course of plasma and erythrocyte ferritin during phlebotomy therapy was analyzed in 3 patients with idiopathic hemochromatosis. Three stages were established: 1. plasma ferritin dropped gradually into the normal range while erythrocyte ferritin remained high, 2. appropriate phlebotomies maintained normal plasma ferritin and high erythrocyte ferritin, and indicated a monthly uptake of dietary iron of 150-200 mg at a steady state, 3. at low plasma ferritin levels, erythrocyte ferritin was rapidly decreased by further intensive phlebotomy therapy. Based on the presumed net removal of iron, 1 microgram/l plasma ferritin was equivalent to 3-6 mg of body iron and 1 microgram/l erythrocyte ferritin to somewhat less than 1 mg of body iron. - An elevated erythrocyte ferritin during phlebotomy therapy in iron overload not only depends on body iron stores like plasma ferritin but may also be regulated by the activity of erythropoiesis.

Fibrinolysis induced by the infusion of plasminogen activators into the circulation has been shown to cause coagulation disorders in ascites retransfusion. Dexamethasone is known to inhibit the synthesis of plasminogen activators by peritoneal macrophages. We therefore assessed its potential in preventing the occurrence of fibrinolysis by injecting 16 mg dexamethasone intraperitoneally in 10 patients 24 h before ascites retransfusion was performed. In addition, the effect of dexamethasone upon the activity or concentration of several proteases and antiproteases related to coagulation in plasma and ascites was analyzed on 15 occasions. An increase of the activity of plasminogen, alpha 2-antiplasmin, and antithrombin III, and in the concentration of alpha 1-protease inhibitor in ascites was induced by the dexamethasone injection. However, the reaction was not identical in all patients. Those patients having an increase of plasminogen activities of 0.6 CTA U/ml or more did not show signs of fibrinolysis during retransfusion. The results obtained indicate that intraperitoneal injection of dexamethasone decreases the concentration of plasminogen activators in ascites and thereby reduces the risk of coagulation disorders during retransfusion procedures. Since the effect is variable and not sustained, assessment of preoperative plasminogen concentrations is mandatory in order to prevent complications.

Differentiation between malignant and nonmalignant ascites by means of laboratory parameters has so far not been completely achieved. One hundred and four patients with ascites (34 malignant, 51 cirrhotic, and 19 other) were studied for fibronectin concentration in ascites. The first 47 patients (13 malignant and 34 cirrhotic) were used to determine mean values and standard deviation (178 +/- 96 vs. 8.3 +/- 15.3 micrograms/ml) and to define a cutoff concentration between both groups (75 micrograms/ml). Several other parameters were analyzed simultaneously in these patients (total protein: 3.93 +/- 1.46 vs. 1.50 +/- 1.02 g/dl; white cell count: 2022 +/- 1153 vs. 569 +/- 405/mm3; lactic acid: 3.86 +/- 2.57 vs. 1.83 +/- 0.72 mmol/L; lactic acid dehydrogenase: 357 +/- 329 vs. 61 +/- 35 U/L; serum/ascites ratio of lactic acid dehydrogenase: 1.11 +/- 1.13 vs. 4.06 +/- 2.00; pH: 7.275 +/- 0.229 vs. 7.513 +/- 0.042). Their accuracy (mean of sensitivity and specificity) was always less than 87% due to a considerable overlap between both groups. Five patients with other causes of ascites could not be classified at all. Application of fibronectin determination on the subsequent 57 patients (21 malignant, 17 cirrhotic, and 19 other) revealed a sensitivity, specificity, and negative and positive accuracy for malignant ascites of 100%. Calculation of these parameters for all 104 patients gave identical values. The inclusion of 3 patients without final diagnosis in the group of nonmalignant ascites reduced specificity to 97.1 and positive accuracy to 94.4%. However, these values were superior to all other methods used so far. Fibronectin determination in ascites in combination with other parameters suitable for exclusion of infectious or pancreatic origin of ascites may prove useful in the differential diagnosis of ascites.

To improve the ability to predict the occurrence of coagulation disorders in ascites retransfusion and, in addition, to better define the nature of the coagulation disorder, several proteases and antiproteases were analyzed in ascites and plasma before ascites retransfusion in 17 patients. Plasminogen, alpha 2-antiplasmin, antithrombin III, and fibrin(ogen) degradation products in ascites were significantly altered in patients who later developed abnormal coagulation as compared to those who did not. Only plasminogen and alpha 2-antiplasmin in ascites achieved a sufficient predictive value for the occurrence of coagulation abnormalities. The pattern of the coagulation abnormalities observed strongly suggests fibrinolysis induced by the infusion of plasminogen activators as the cause of the coagulation disorder in ascites retransfusion procedures.

In order to define the clinical significance and the need for further clinical work-up in patients where abnormalities of the stomach or bowel are found by ultrasound, we performed a prospective study on 100 patients with such findings. Of all patients, 35% were found to have a malignant tumor, 73% had a diagnosis as made by reference methods which was probably (18%) or definitively (55%) related to the US finding. Eighteen percent had definitive false positive findings, in 9% no final diagnosis was obtained. Thus, a positive predictive value of 80% was calculated for the US finding of a mass or a target sign related to bowel or stomach in US. The positive predictive value was lowest for target signs related to the bowel (75%) and highest for bowel conglomerates (100%). Patients with target signs of the stomach, bowel conglomerates, or masses were more likely to have malignant disorders (72%) than those with target signs related to the bowel (16%). We conclude from this study that the ultrasound finding of a target sign or a mass related to stomach or bowel has a high clinical relevance and should in any case worked up by appropriate investigations when clinical consequences are possible.

19% of 1490 abdominal sonograms from 1192 patients led to findings which were not related to the original purpose of the sonogram or to the actual disease, and of which neither the treating physician nor the patient were aware. The most frequent findings were those in liver, kidneys and gallbladder. The majority of ultrasonographically detected lesions were benign; tumour diseases were suspected only in 26 cases. The incidence of such findings increased with the patients' age. The positive, predictive value of the findings was around 90%. In 20% of the patients with unexpected findings, further diagnostic measures were taken; therapeutic consequences were recorded in only twelve cases. Further measures were recommended in 20% of the patients, a majority of which had pancreatic and vascular abnormalities. Because such findings may considerably facilitate the diagnosis of subsequent complaints, all accessible organs should be examined during abdominal ultrasonography.

In 502 patients, length, thickness and width of the spleen as well its location with respect to the ipsilateral kidney were determined by means of ultrasonography, and a relationship was established with the incidence of diseases accompanied by enlargement of the spleen. A significant correlation to the incidence of such diseases was found only with respect to spleen thickness. The probability of a corresponding disease was 80% for a spleen thickness of 5 cm, 90% for 6 cm and 100% for more than 7 cm. A comparison between palpation and ultrasonography supported the fact that enlargement of the spleen can, in many cases, not be ascertained by palpation, but that palpation findings are indeed positive in splenic enlargement of minor degree. The most suitable parameter for ultrasonographic detection of splenomegaly is thus spleen thickness, for which a limit value of 5 cm should be assumed. If the spleen is found to exceed this value, further examinations are indicated to clarify the underlying disease.

Vascular disorders of the liver except portal hypertension are rare. They can be visualised via ultrasound, as demonstrated by two cases of cavernous transformation of the portal vein, one case of Osler's disease of the liver, and one case of Budd-Chiari's syndrome. The cavernous transformation and the occlusion of the hepatic veins can be diagnosed by ultrasound, while Osler's disease cannot be differentiated with certainty from other disorders.

By using a four-step procedure (i, solubilization with Triton X-100; ii, affinity chromatography on concanavalin A-Sepharose; iii, affinity chromatography on wheat germ lectin-Sepharose; iv, preparative sodium dodecyl sulfate gel electrophoresis) a glycoprotein was isolated from rat liver plasma membrane. The molecular weight is 110,000 and the isoelectric point is 5.8. It contains L-fucose, N-acetylneuraminic acid, D-galactose, D-mannose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, and considerable quantities of aspartate, threonine, serine, and leucine. In pulse-chase experiments the half-lives of methionine and arginine, representing the half-life of the protein, were determined as 70 hr and 78 hr, respectively. The half-lives of the terminal carbohydrates L-fucose and N-acetylneuraminic acid were 12.5 and 33 hr, respectively. The galactose half-life was 20 hr. From this it is concluded that terminal sugars turn over several times in the life-span of this protein molecule. This process may be operative during membrane recycling mechanisms.

Dipeptidylaminopeptidase IV, a plasma membrane-bound glycoprotein, is characterized by an intramolecular heterogeneous turnover of the protein backbone and carbohydrate chain. The faster turnover of the latter is restricted only to the outer sugars. The inner core sugars D-mannose and N-acetyl-D-glucosamine turn over at the same rate as the protein backbone.

The concentrations of several proteases and antiproteases known to be present in ascites were tested in plasma and ascitic fluid with regard to their ability to separate ascites according to malignant or nonmalignant disease. Seventeen patients with proven malignant ascites and 37 with ascites due to liver cirrhosis were included. Activities of plasminogen, alpha 2-antiplasmin, antithrombin-III, and factor V, and the concentration of alpha 1-protease inhibitor were significantly higher in the plasma of patients with malignant ascites than in cirrhotic patients. Fibronectin, plasminogen, alpha 2-macroglobulin, alpha 1-protease inhibitor, antithrombin-III, and albumin revealed higher concentrations or activities in malignant ascites than in cirrhotic ascites. Due to a wide variation of most parameters, only fibronectin, antithrombin III, and alpha 1-protease inhibitor in ascites had a sensitivity and specificity higher than 90% for malignant ascites. When the specific protein/albumin ratio was used, only the accuracy of fibronectin was increased reaching a sensitivity and specificity of 100%. The plasma/ascites gradients of the proteins assessed differed significantly, that of fibronectin being much higher (22 +/- 7) than that of all other proteins. In malignant ascites fibronectin concentration was only correlated with alpha 1-protease inhibitor concentration but not with the concentration or activity of all other proteins, while in cirrhotic ascites most proteins revealed a positive correlation. The determination of the fibronectin concentration or the fibronectin/albumin ratio in ascites can differentiate malignant and nonmalignant ascites. All other proteases and antiproteases assessed are of lesser value for this purpose, although most are significantly increased in ascites and plasma of patients with malignant disorders.

The accuracy of ultrasonography in the detection of liver metastases was studied in 245 patients. Sensitivity, specificity and positive and negative accuracy were defined and calculated. Taking into account only metastases more than 15 mm in diameter, sensitivity was 75.5%, positive accuracy was even higher at 83.0%. Specificity and negative accuracy were above 90%. The results are largely dependent on the type of primary tumour. Sensitivity for metastases of a bronchial or gastric carcinoma was about 50%. The results indicate that a positive ultrasound finding generally need not be checked by other methods, while a negative result, especially in certain types of tumour, is by no means sufficient to exclude metastases.

Sonographically guided puncture of intra-abdominal and retro-peritoneal masses for cytological diagnostic is widely employed. However, processing of cytological material may result in artifacts and in the case of certain malignant tumours, of benign tumours or diffuse organ changes, cytology is only relatively reliable. Special experience on the part of the investigato is therefore required. Hence, in far-reaching therapeutic decisions such as operation, cytostatic therapy or radiotherapy, diagnosis based on histological findings is preferred. Preliminary experience with a new type of fine needle (Schneidbiopsiekanüle) suitable for obtaining histological material is presented.

Since 1981 in the University Hospital of Freiburg 41 patients with ascites have been treated by installation of a peritoneo-venous shunt system. In 9 patients thrombotic complications occurred. Two patients had to undergo a second surgical treatment. Seven patients have been treated by local fibrinolysis. In 6 patients local fibrinolytic therapy was partly or completely successful, in one patient local fibrinolysis was of no therapeutic effect.

Ultrasound is the method of choice in the detection and differentiation of solid or cystic masses in the abdomen. The differential diagnosis of anechoic and hypoechoic lesions comprises a large variety of benign and malignant diseases or abnormalities. This paper describes a number of such lesions and, in addition, discusses the possible differential diagnoses so far reported in the literature. An attempt is made to describe the different features of such lesions. Most of them are rare but have to be considered if a lesion of unknown origin or clinical relevance is detected by ultrasound.

Complications occurred in 29 of 37 patients after ascites retransfusion (n = 16) or introduction of a peritoneovenous shunt (n = 21). Blood clotting disturbances, that could either be successfully treated with drugs or which led to interruption of the reinfusion, appeared in 38%. Estimation of plasminogen proved to be of reliable prognostic value thus enabling prophylactic measures to be taken. Post-operatively 14 patients had transient fever not requiring specific treatment. Local fibrinolysis or shunt revision was successful in three patients with shunt thromboses. According to our experience most complications can be avoided by prophylactic and therapeutic measures.

Studies of the expression of selected genes within the intestinal mucosa will provide important new information about physiologic pathological processes that effect mucosal growth, differentiation, and function. To study gene expression in the gut, we developed a method to obtain sufficient undegraded RNA from human endoscopic intestinal biopsy specimens for Northern and slot blot analysis. To verify the method, we examined the differential expression of HLA class II genes in small intestinal mucosa. Levels of RNA transcripts for HLA-DR, -DP, and -DQ alpha and beta chains were assessed in freshly isolated endoscopic intestinal mucosal biopsy specimens and compared with levels in Epstein-Barr virus transformed B cells from the same individuals. Sufficient undegraded cellular RNA with distinct 28S and 18S ribosomal bands could be obtained from as few as two 2-3 mm endoscopic biopsies. Using chain and locus specific cDNA probes, HLA-DR, -DP, and -DQ subregion genes were shown to be expressed in intestinal mucosa, with the relative magnitude of RNA transcripts being DR greater than DP greater than DQ. The same hierarchy of expression was seen for EBV-transformed B cell lines. This method, in conjunction with the polymerase chain reaction for amplifying specific RNA transcripts and in situ hybridisation methods for the cellular localisation of RNA transcripts, will enable studies on the regulation of gene expression in the intestinal mucosa.