Faculty Bibliography

To identify disease-specific T cell changes that occur in Crohn's disease (CD), the T cell receptor BV repertoires of lamina propria lymphocytes (LPL) isolated from both the inflamed and "disease-inactive" colons of seven CD patients were compared by the quantitative PCR and DNA sequence analysis. It was observed that the BV repertoires of LPL isolated from the disease-active and disease-inactive parts of the colon from the same individual were very different. Furthermore, nearly all of the differences occurred in CD4+ LPL, with very few differences in the CD8+ population of LPL. Although the pattern of BV segments that was increased in disease-active tissue relative to disease-inactive tissue was different for all seven CD patients, there were several BV segments that increased uniformly in the disease-active tissue of all seven individuals. CDR3 length analysis and DNA sequencing of these BV segments revealed that in six of the seven CD patients there was a striking degree of oligoclonality that was absent from disease-inactive tissue of the same individual. These observations suggest that at least some of the inflammation in CD is the result of responses by CD4+ T cells to specific antigens. The isolation of such inflammation-specific CD4+ T cells may make it possible to identify the antigens that are responsible for the inflammatory process in CD and provide a better understanding of its pathogenesis.

To identify disease-specific T cell changes that occur in Crohn's disease (CD) the T-cell receptor (TCR) BV repertoires of lamina propria lymphocytes (LPL) from both disease-active and disease-inactive colonic tissue of three CD patients were compared by a quantitative polymerase chain reaction (qPCR) and CDR3 length analysis. It was observed that the BV repertoires of LPL isolated from the disease-active and disease-inactive parts of the colon of the same individual were different, and most of the differences occurred in CD4+ LPL with very few differences in the CD8+ populations of LPL. Although the pattern of BV segments that was increased in disease-active relative to disease-inactive tissue was different for all three CD patients, there was an increase in the levels of BV11, 13S2, 15, 16, and 17 segments in the disease-active tissue of all three patients. Standard CDR3 length analysis of BV11, 13S2, 15, 16, and 17 segments revealed that in two of the three CD patients there was a striking degree of TCR oligoclonality in the disease-active tissue that was absent from disease-inactive tissue of the same individual. Additional differences between the disease-active and disease-inactive tissues were observed using a more refined method of CDR3 length analysis, which employs BV- and BJ-specific primers. These observations suggest that at least some of the inflammation in CD is the result of responses by CD4+ T cells to specific antigens.

: Crohn's disease (CD) and ulcerative colitis (UC) are idiopathic inflammatory bowel diseases (IBD) that are characterized by chronic intestinal inflammation and are associated with abnormalities of peripheral and mucosal immune function. The aim of our study was to determine whether CD or UC is characterized by discrete profiles of intestinal lymphokine production. Total cellular RNA was isolated from biopsies of healthy controls and from patients with IBD. Messenger RNA transcript levels in biopsies were determined for interleukin-2 (IL-2), IL-4, IL-5, and interferon-gamma (IFN-gamma), using a quantitative reverse transcriptase polymerase chain reaction method. Compared with inflamed UC mucosa and controls, CD mucosal lesions contained higher IL-2 and IFN-gamma mRNA (p < 0.05), which is consistent with a T-helper cell 1 (Th1)-like pattern. In UC, IL-5 mRNA content was higher in involved areas compared with controls (p < 0.05) and inflamed CD lesions (p < 0.05), suggestive of a Th2 pattern. We conclude that the intestinal mucosa of CD and UC have inflammatory responses characterized by discrete T-helper profiles of lymphokines. This strongly suggests that the immunopathogenesis of these two forms of IBD are different.

To identify disease-specific T cell changes that occur in Crohn's disease (CD), the T cell receptor (TCR) BV repertoires of lamina propria lymphocytes (LPL) isolated from the diseased colon of seven CD patients and eight controls were determined by semiquantitative polymerase chain reaction (qPCR). As an internal control for the effects of HLA and other genes on the TCR repertoire, the BV repertoires of peripheral blood lymphocytes (PBL) from the same individuals were similarly determined and used for comparison. It was observed that the BV repertoires of LPL and PBL within the same individual were very different in both the CD and control groups. However, the CD4+, but not CD8+, repertoires of LPL and PBL differed to a much greater extent in the CD group than in the control group. Furthermore, in each CD patient there was a unique pattern of BV segments which were increased in the CD4+ LPL repertoire relative to that in PBL. These observations suggest that the inflammatory process in CD involves responses by specific CD4+ T cells to specific antigens. The isolation of such inflammation-specific CD4+ T cells may make it possible to identify the antigens which are responsible for the inflammatory process in CD and provide a better understanding of its pathogenesis.

The TCR repertoires of CD4+ and CD8+ lamina propria and peripheral blood lymphocytes (PBL) were compared with respect to V beta frequencies and oligoclonality. Disease-free colon specimens and paired peripheral blood samples were obtained from eight adult patients undergoing surgical resections for colorectal carcinoma. Mononuclear cell were isolated from the lamina propria and peripheral blood and separated into CD4+ and CD8+ cells by immunomagnetic adsorbtion. Analysis of V beta frequencies by qPCR revealed that PBL and lamina propria lymphocytes (LPL) from the same individual have very different repertoires, especially within the CD8+ population. Furthermore, CD8+, but not CD4+, LPL display extensive oligoclonality, similar to that which has previously been reported for CD8+ PBL. However, the oligoclonal receptors observed in CD8+ LPL are, in general, distinct from those observed in CD8+ PBL, and differ for each individual. These observations indicate that the TCR repertoires of LPL are as diverse as PBL, and suggest that LPL and PBL are normally exposed to different sets of antigens. In addition, these observations provide a baseline for examining the effects of various disease states and environmental insults on the LPL repertoire.

Hyposplenism as a complication of celiac sprue confers an increased risk of pneumococcal sepsis, but such patients do not routinely receive pneumococcal vaccine despite reports of overwhelming pneumococcal sepsis. Because antibody response in these patients has not been previously assessed, we measured pre- and postvaccination levels in 10 patients with documented sprue. All demonstrated appropriate acute antibody responses to a polyvalent pneumococcal vaccine. Vaccination of all patients with celiac sprue seems appropriate.