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Biomedical subjects

S R Targan

Publications and source records attributed to S R Targan.

At least 91 records · Page 5Linked to original sources
PubMed1995

Pouchitis disease course after orthotopic liver transplantation in patients with primary sclerosing cholangitis and an ileal pouch-anal anastomosis.

OBJECTIVE: Primary sclerosing cholangitis is associated with the development of pouchitis after ileal pouch-anal anastomosis for ulcerative colitis. This study determined the effect of liver transplantation for primary sclerosing cholangitis on the disease course of pouchitis. METHODS: Seven patients with an ileal pouch-anal anastomosis for ulcerative colitis underwent liver transplantation for primary sclerosing cholangitis. The medical record was reviewed to determine the pouchitis activity and pattern (no pouchitis, single acute, recurrent acute, chronic) before and after transplantation. RESULTS: Five of seven patients had pouchitis before transplant [recurrent acute (n = 3), chronic (n = 2)], and four of those five continued to have pouchitis after transplant (all chronic). Pretransplant sera were positive for antineutrophil cytoplasmic antibody in 6/6 patients, compared to 5/6 patients posttransplant. One patient with pouchitis pretransplant became negative for antineutrophil cytoplasmic antibody posttransplant but continued to have pouchitis. CONCLUSION: Pouchitis occurs frequently in patients with primary sclerosing cholangitis and an ileal pouch-anal anastomosis for ulcerative colitis. Liver transplantation does not alter the disease course of pouchitis for most of these patients.

Adult↗
PubMed1994

Expression of a novel autoantibody defined by the VH3-15 gene in inflammatory bowel disease and Campylobacter jejuni enterocolitis.

This study newly introduces anti-VH mAbs to assess the role of clonal B cell activity in inflammatory bowel disease. Immunohistochemistry of colonic biopsies in ulcerative colitis (UC) and Crohn's disease (CD), but not unaffected individuals, demonstrated uniform staining of intravascular erythrocytes with BK2, a monoclonal specific for the VH3-15 Ig heavy chain gene product. Staining was caused by erythrocytes opsinized in vivo by anti-erythrocyte Abs present in patient sera and by using the VH3-15 gene product. The erythrocyte Ag was identified by immunoprecipitation as 22- and 28-kDa membrane proteins. A direct flow cytometric assay was developed to measure this serum autoantibody and was tested in 101 individuals with UC, CD, other acute or chronic colitis, and healthy controls. Compared with normal subjects, BK2+ anti-erythrocyte Abs were elevated in most sera from patients with CD and UC (including postcolectomy). BK2+ anti-erythrocyte Abs also were elevated in 10 of 38 noninflammatory bowel disease patients, all of whom had Campylobacter jejuni enterocolitis. These findings suggest that a common immunopathogenetic factor, manifested by VH3-15 B cell activation may be shared in UC, CD, and Campylobacter jejuni enterocolitis.

Amino Acid Sequence↗
PubMed1994

Immunomodulator therapy in inflammatory bowel disease.

The introduction of immunomodulator therapy in the treatment of patients with inflammatory bowel disease (IBD) has provided an important tool in modifying the mucosal immune system thought to be important in the pathogenesis of IBD. Currently available immunomodulating agents include azathioprine, 6-mercaptopurine, cyclosporin, and methotrexate. Recent clinical trials have demonstrated that these agents have an important therapeutic role in the treatment of patients who are either refractory or intolerant to traditional medical therapy. They are useful in the induction and maintenance of remission for both ulcerative colitis and Crohn's disease. However, these agents have significant toxicities and limited efficacy. In addition, potential risks of malignancy and infection limit their indiscriminate use. Thus, with the better understanding of the molecular basis of mucosal immunity, innovative immune-modifying therapies, such as antagonists of cytokines and inhibitors of T-cell activation, are being developed. It is likely that these exciting developments will soon result in specific immune modulating therapy with improved efficacy and reduced toxicity in the treatment of patients with IBD.

Antibodies, Monoclonal↗
PubMed1994

Anti-neutrophil cytoplasmic antibodies in children with ulcerative colitis.

Tests that positively identify individuals with ulcerative colitis, distinguishing them from patients with Crohn disease or other causes of colitis, have not been reliable. Genetic predisposition to inflammatory bowel diseases and genetic influence on immune regulation resulted in the clinical evaluation of potential serologic markers. In adults the presence of anti-neutrophil cytoplasmic antibody (ANCA) in serum identifies patients with ulcerative colitis. In this study we demonstrated that high levels of ANCA are present in 83% of children and adolescents with ulcerative colitis. Furthermore, the majority of patients with ulcerative colitis had a perinuclear pattern of these antibodies by indirect immunofluorescence. The combination of a positive ANCA and perinuclear indirect immunofluorescence pattern was 97% specific for ulcerative colitis. We conclude that determination of ANCA is a sensitive and specific clinical test for identification of children and adolescents with ulcerative colitis.

Adolescent↗
PubMed1993

Ulcerative colitis and total alopecia in a mother and her son.

Extraintestinal autoimmune disorders are associated with ulcerative colitis in selected patients and lend support to the theory of immune-mediated injury in inflammatory bowel disease. Rarely, alopecia areata has been associated with ulcerative colitis, and familial aggregation and an HLA association have been reported for both disorders. The occurrence of both alopecia and ulcerative colitis in a mother and son are reported with a detailed investigation of antineutrophil cytoplasmic antibodies and HLA alleles in this family. Treatment with the immunosuppressive agent cyclosporine proved beneficial in the child leading to remission of the ulcerative colitis and nascent growth of scalp and body hair.

Adult↗
PubMed1993

Distinct associations of HLA class II genes with inflammatory bowel disease.

BACKGROUND: There are relatively few studies of HLA class II association either with Crohn's disease (CD) or ulcerative colitis (UC). The few available association studies have been carried out by serological techniques, and the results from these studies are inconclusive. METHODS: The association between HLA class II genes was studied using molecular genotyping in combination with allele-specific oligonucleotide hybridization by polymerase chain reactions. RESULTS: In UC (n = 74), we observed a positive association with the HLA DR2 allele (P = 0.008) and negative associations with the DR4 (P = 0.018) and DRw6 (P = 0.028) when compared with ethnically matched controls (n = 77). No associations were observed with any DQ alleles. In contrast, in CD (n = 95) we observed a positive association with the combination of DR1 and DQw5 alleles (P = 0.021). Furthermore, stratifying DR1 and DQw5 alleles indicated that neither allele was independently associated with CD, suggesting that the association was with the haplotype rather than either of the alleles individually. A suballele of DQw5, DQB1*0501, contributed this haplotypic association (P = 0.012). CONCLUSIONS: DR and DQ molecules firmly separate UC and CD on genetic grounds, suggesting that the contribution of the HLA class II genes to the disease susceptibility is quite different for the two disorders.

Alleles↗
PubMed1993

Familial empirical risks for inflammatory bowel disease: differences between Jews and non-Jews.

The Jewish population has an increased frequency of inflammatory bowel disease compared with their non-Jewish neighbours. Genetic factors have been implicated in the aetiology of this disorder and may contribute to ethnic differences. This study determined the familial empirical risks for inflammatory bowel disease in the first degree relatives of inflammatory bowel disease probands (for both Jews and non-Jews) for the purpose of accurate genetic counselling and genetic analysis. A total of 527 inflammatory bowel disease patients from Southern California (291 Jews and 236 non-Jews) were questioned about inflammatory bowel disease in their first degree relatives (a total of 2493 individuals). Since inflammatory bowel disease has a variable and late age of onset, age specific incidence data were used to estimate the life time risks and to make valid comparisons between the different groups. In the first degree relatives of non-Jewish probands, the life time risks for inflammatory bowel disease were 5.2% and 1.6% when probands had Crohn's disease and ulcerative colitis respectively. These values were consistently lower than the corresponding risks for relatives of Jewish patients -7.8% and 4.5% for Crohn's disease and ulcerative colitis probands respectively (p value for comparison between Jews and non-Jews: 0.028; between ulcerative colitis and Crohn's disease: 0.005). These data provide the requisite basis for genetic counselling for these disorders in the white American population. In addition, these different empirical risks for relatives of Jewish and non-Jewish probands allow rejection of single Mendelian gene models for inflammatory bowel disease, but are consistent with several alternative genetic models.

Adolescent↗
PubMed1993

Ulcerative colitis: a genetically heterogeneous disorder defined by genetic (HLA class II) and subclinical (antineutrophil cytoplasmic antibodies) markers.

Newly described distinct associations of HLA class II genes with ulcerative colitis (UC) (DR2) and Crohn's disease (CD) (DR1/DQ5) provide strong evidence for genetic heterogeneity of susceptibility between these two forms of inflammatory bowel disease. A familial distribution of antineutrophil cytoplasmic antibodies (ANCAs, a subclinical marker of UC) in UC families has further implied the existence of heterogeneity within UC. To test the hypothesis that the heterogeneity within UC indicated by ANCAs has a genetic basis that resides within the HLA region, we studied 89 UC cases and an ethnically matched control group (n = 50). Serological and molecular typing techniques were applied to define HLA class II genes (DR, DQ). ANCAs were detected using an enzyme-linked immunosorbent assay, and positive values were confirmed by indirect immunofluorescence. We observed that ANCA-positive UC patients (n = 70) had a significantly increased frequency of DR2 compared with ANCA-negative controls (n = 46) (44% vs 22%, P = 0.01). In contrast, the frequency of DR2 in ANCA-negative UC cases (21%) was virtually identical to that in controls (22%, P = 0.9). Furthermore, the ANCA-negative UC patients had an increase in the DR4 allele compared with ANCA-positive UC (P = 0.004). Thus, with the combination of a subclinical marker (ANCAs) and molecular genetic markers, genetic heterogeneity has been demonstrated within UC: ANCA-positive UC associated with DR2, and ANCA-negative UC likely associated with DR4.

Adult↗
PubMed1992

Neutrophil autoantibodies in ulcerative colitis: familial aggregation and genetic heterogeneity.

The possibility that the neutrophil autoantibodies associated with ulcerative colitis represent a genetic marker of susceptibility was investigated by determining their prevalence in unaffected relatives of patients. Neutrophil autoantibodies were detected using an enzyme-linked immunosorbent assay, and positive values were confirmed by indirect immunofluorescence. An increased prevalence of neutrophil antibodies was found not only in the probands (68%, 26/38) but also in their clinically unaffected family members (15.7%, 17/108) compared with controls (2.9%, 1/35) (P less than 0.0001 and P less than 0.05, respectively). These results were confirmed with sera from a second center, where 86.4% (19/22) of probands were positive and 20.9% (9/43) of their relatives were positive. The prevalence of neutrophil autoantibodies in the relatives of probands who were antibody positive (21.4%) was significantly greater than the prevalence in relatives of probands who were antibody negative (7%; P less than 0.05). The findings are consistent with these antibodies being a potential marker of genetic susceptibility to ulcerative colitis and suggest the possibility of genetic heterogeneity within this disease.

Adolescent↗
PubMed1992

Ulcerative colitis-linked antineutrophil cytoplasmic antibody in the cotton-top tamarin model of colitis.

The presence of antineutrophil cytoplasmic antibodies (ANCA) in serum has recently been shown to be a good disease marker for ulcerative colitis. An animal model of colitis expressing serum ANCA would allow prospective studies of the relationship between ANCA expression and development of colitis. The cotton-top tamarin model of spontaneous colitis was investigated for presence of ANCA to evaluate its potential as a model for the study of the immune response in human ulcerative colitis. Results show that cotton-top tamarin neutrophils have antigens recognized by immunoglobulin G (IgG) from the ANCA-positive serum of patients with ulcerative colitis. However, cotton-top tamarins do not generate serum IgG reactive to cotton-top tamarin or human neutrophils even when equal amounts of IgG are used for antigen detection. As new animal models of spontaneous and induced chronic colitis are developed, the presence of ANCA in serum, using the species' neutrophils, will be useful in relating the immune response of the model to that in human ulcerative colitis.

Animals↗
PubMed1991

Oral mesalamine (Asacol) for mildly to moderately active ulcerative colitis. A multicenter study.

OBJECTIVE: To evaluate the efficacy and safety of a pH-sensitive, polymer-coated oral preparation of mesalamine in patients with mildly to moderately active ulcerative colitis. DESIGN: A multicenter, double-blind, placebo-controlled randomized trial. SETTING: Five university-based medical centers, one inflammatory bowel disease center, and three private practice sites. PATIENTS: A total of 158 patients with newly or previously diagnosed active ulcerative colitis. INTERVENTION: A pH-sensitive, polymer-coated oral preparation of mesalamine (5-aminosalicylic acid) was used at 1.6 and 2.4 g/d for 6 weeks. MEASUREMENTS: Efficacy was measured by scores for stool frequency, rectal bleeding, patient's functional assessment, sigmoidoscopic findings, and physician's global assessment. Stringent criteria for disease activity were established prospectively. RESULTS: The analysis of protocol-compliant patients showed a significant improvement at 3 weeks in patients taking 2.4 g/d of mesalamine compared with patients taking placebo (32% versus 9%; P = 0.003). At 6 weeks, both the 1.6 g/d (43%) and 2.4 g/d (49%) doses were significantly superior to placebo (23%) (P = 0.03 and P = 0.003, respectively). In addition, more patients worsened in the placebo group compared with the 2.4 g/d group (50% versus 19%; P = 0.003); however, there was no statistically significant difference in worsening between the 1.6 g/d mesalamine group and the placebo group. The oral mesalamine tablet was well tolerated, and no clinically significant changes were observed in hematologic, hepatic, or renal laboratory profiles. CONCLUSION: Colon-targeted oral mesalamine at 2.4 g/d is effective therapy for mildly to moderately active ulcerative colitis. It is well tolerated and should provide a viable therapeutic alternative to sulfasalazine.

Administration, Oral↗
PubMed1991

Anti-neutrophil cytoplasmic antibodies in ulcerative colitis. Comparison with other colitides/diarrheal illnesses.

Previous studies from this laboratory showed that serum anti-neutrophil cytoplasmic antibodies, distinct from those associated with active Wegener's granulomatosis, are present in the majority of patients with ulcerative colitis. In this study, the specificity of anti-neutrophil cytoplasmic antibodies for ulcerative colitis as compared with other colitides and diarrheal illness was determined. In a blinded study, test samples of serum were screened for anti-neutrophil immunoglobulin G in a fixed neutrophil enzyme-linked immunosorbent assay. Levels of neutrophil binding by immunoglobulin G and titers of anti-neutrophil immunoglobulin G in sera from patients with ulcerative colitis and patients with ulcerative colitis post colectomy were each significantly greater than the levels and titers for normal controls and patients with a variety of other colitides and diarrheal illnesses. Levels of neutrophil binding for colonic Crohn's disease, bacterial/amoebic colitis, the irritable bowel syndrome with diarrhea, and other miscellaneous diarrheal illnesses were not significantly different than the levels for normal controls. Although the levels of binding for collagenous colitis were significantly less than the levels for ulcerative colitis, they were significantly greater than the levels for normal controls. Patterns of neutrophil binding by serum samples that were positive in the enzyme-linked immunosorbent assay were determined by indirect immunofluorescence. Perinuclear staining was the predominant pattern shown by sera from patients with ulcerative colitis. The combination of a positive value in the enzyme-linked immunosorbent assay and a perinuclear immunofluorescence pattern was 60% sensitive and 94% specific for ulcerative colitis. It is concluded that anti-neutrophil cytoplasmic antibodies in ulcerative colitis are not simply an epiphenomenon related to inflammation of the colon. Identification of the antigen(s) to which these autoantibodies are directed may facilitate understanding of the underlying immune response and may allow development of an assay that is more sensitive and specific for ulcerative colitis.

Adult↗
PubMed1991

Triggered human mucosal T cells release tumour necrosis factor-alpha and interferon-gamma which kill human colonic epithelial cells.

T cell activation can lead to local tissue injury in organ culture studies of human fetal jejunum, either directly through cytotoxicity or indirectly by the release of cytotoxic cytokines. The goal of this study was to establish in vitro whether cytotoxic cytokines can be released by isolated colonic T cells and what cytokine interactions are required for killing of human colonic epithelial cells. Cytokine-containing supernatants were induced by incubating unseparated lamina propria lymphocytes (LPL) or mucosal T cell subpopulations (separated by indirect panning) with anti-CD3 and/or K562 target cells for 18 h at 37 degrees C. Cytokines were measured by cytotoxicity assays using L929 (murine fibroblast) and HT-29 (human colonic tumour) lines as target cells in combination with blocking anti-cytokine antibodies. Supernatants derived from unseparated, CD4+ (greater than 95% pure) and CD8+ (greater than 90% pure) LPL were cytotoxic to L929 targets (350 U/ml, 230 U/ml and 100 U/ml tumour necrosis factor-alpha, respectively). All or nearly all of the cytotoxicity was due to the presence of tumour necrosis factor-alpha (little or no tumour necrosis factor-beta was detected). These same supernatants were cytotoxic (up to 32% lysis at 1/4 dilution) to HT-29 targets in a 48-h 111In release assay. Recombinant tumour necrosis factor-alpha and interferon-gamma alone produced minimal killing of HT-29, but together killed the HT-29 target cells. Anti-tumour necrosis factor-alpha or anti-interferon-gamma alone blocked killing of HT-29 target cells by LPL-derived supernatants, although anti-tumour necrosis factor-beta had no effect upon killing of HT-29. These results demonstrate that human LPL T cells, triggered by addition of anti-CD3 and target cells, produce tumour necrosis factor-alpha and interferon-gamma, both of which are required for optimal killing of HT-29. Simultaneous release of these cytokines in the vicinity of epithelial cells during immune responses could play an important role in the mucosal damage in chronic inflammatory states such as inflammatory bowel disease.

Antibodies, Monoclonal↗
PubMed1991

Neutrophil cytoplasmic antibodies: a link between primary sclerosing cholangitis and ulcerative colitis.

Whether serum autoantibodies to neutrophil cytoplasmic components, previously found in ulcerative colitis, are also associated with primary sclerosing cholangitis was determined. In an enzyme-linked immunosorbent assay for immunoglobulin G neutrophil antibodies, neutrophil binding by primary sclerosing cholangitis sera was significantly greater than that for primary biliary cirrhosis, chronic hepatitis B, and chronic non-A, non-B hepatitis. Similar differences were seen when sera from patients with primary sclerosing cholangitis without evidence for ulcerative colitis were compared with sera from liver disease controls. Perinuclear immunofluorescence staining of neutrophils was exhibited by the majority of ulcerative colitis, primary sclerosing cholangitis, and primary sclerosing cholangitis without ulcerative colitis sera. The combination of elevated immunoglobulin G neutrophil antibodies and a perinuclear pattern was 65% sensitive and 100% specific for primary sclerosing cholangitis compared with the liver disease control sera. It is concluded that neutrophil cytoplasmic antibodies in ulcerative colitis and primary sclerosing cholangitis may be markers of shared underlying immunopathogenic mechanisms. Identification of the target antigen(s) may facilitate understanding of the underlying immune response and development of an improved disease marker assay.

Autoantibodies↗