ORIGINAL ARTICLE
Prospective Evaluation of Intestinal Homing Memory T Cells
in Ulcerative Colitis
A. L. Hart,* M. A. Kamm,* S. C. Knight,† and A. J. Stagg†
Background: Intestinal homing (7
+
) memory T cells reflect the
mucosal environment in which they were primed. We hypothesized
that prospective assessment of cytokine production by intestinal hom-
ing (7
+
) memory T cells in ulcerative colitis patients followed from
remission to early relapse may elucidate shifts in cytokine production
relevant to the mucosal environment associated with the early phase
of inflammation.
Methods: Twelve patients with frequently relapsing ulcerative co-
litis (2 relapses in the previous 12 months) were recruited in remis-
sion and followed prospectively until relapse. Antibody labeling of
whole blood and flow cytometry were used to identify 7
+
cells and
7
-
populations within CD3+CD45RA- leukocytes. Production of
cytokines (IFN-, TNF-, IL-2, IL-10, TGF-, and IL-4) was deter-
mined by intracellular labeling.
Results: Early relapse of ulcerative colitis was associated with a
shift of T cells from the naive to the memory T cell pool, and further
the ratio of 7
+
:7
-
memory T cells was significantly reduced at re-
lapse (p < 0.01). A greater proportion of intestinal homing 7
+
memory T cells produced IL-4 (p < 0.02) and TNF- (p < 0.05) at
disease relapse compared with remission. Non-intestinal homing 7
-
memory T cells also showed a tendency toward an increased produc-
tion of T
H
1 and T
H
2 cytokines.
Conclusions: The earliest phase of intestinal inflammation in ulcer-
ative colitis patients is associated with an increase in both T
H
1 (TNF-
) and T
H
2 (IL-4) cytokines by intestinal homing 7
+
memory T
cells. These data support the principles of targeting lymphocyte traf-
ficking as therapies in ulcerative colitis.
Key Words: 7 integrin, intestinal homing, intracellular cytokines,
lymphocyte, ulcerative colitis
(Inflamm Bowel Dis 2004;10:496–503)
U
lcerative colitis (UC) is a chronic inflammatory bowel
disease characterized by periods of remission and relapse
in which a combination of genetic and environmental factors
results in a mucosal inflammatory reaction. Changes in muco-
sal cytokine balance have been postulated to play an important
role in the earliest stages of relapse and in the amplification of
intestinal inflammation. There are conflicting reports regard-
ing the nature of the cytokine profile in UC with dysregulated
production of both T
H
1 (IFN- and TNF-) and T
H
2 (IL-5 and
IL-4) cytokines documented.
1–5
Furthermore, cytokine bal-
ance is likely to be different in the earliest phases of relapse
compared with the setting of established inflammation. In oxa-
zolone-induced colitis in mice with histopathological features
resembling those of ulcerative colitis, IL-4 is produced during
the early phase of inflammation but is superseded by the pro-
duction of IL-13 in established disease.
6
Lymphocyte homing from blood into specific tissues is
mediated by different combinations of adhesion and chemoat-
tractant receptors at distinct anatomic sites.
7,8
For example,
selective homing of blood lymphocytes into intestinal tissue is
determined in part by the interaction between the integrin
47 on lymphocytes and mucosal addressin cell adhesion
molecule-1 (MAdCAM-1) expressed on venules in the gut.
9–13
Expression of 47 on circulating memory T cells allows sub-
division of memory T cells into 47+ T cells that home to
mucosal lymphoid tissue and 47- T cells that preferentially
circulate through non-mucosal sites.
14,15
Several observations indicate that circulating 47+
memory T cells reflect the mucosal environment in which they
were primed. In patients with rotavirus infection, a pathogen
that replicates only in the intestine, immunologic recall re-
sponses to rotavirus are found predominantly in the circulating
47+ memory cells, whereas the response to intramuscular
mumps vaccination, which does not involve mucosal priming,
is found in 47- memory cells.
16,17
In addition, pathogen-
specific B-cells are enriched for 47+ cells in the blood of
patients with bacterial diarrhea compared with healthy con-
trols.
18
The local environment within intestinal lymphoid tis-
sue appears to direct the expression of 47 on T cells, target-
ing the resulting effector T cells to the intestinal tissue,
19
with
a central role for tissue-derived antigen-presenting dendritic
cells.
20
Received for publication October 6, 2003; accepted February 19, 2004.
From *St Mark’s Hospital, Harrow, United Kingdom; and †Antigen Presen-
tation Research Group, Imperial College London, Northwick Park Cam-
pus, Harrow, United Kingdom.
Supported by Wellcome Trust and Medical Research Council (UK).
Reprints: Dr A. J. Stagg, Antigen Presentation Research Group, Imperial Col-
lege London, Northwick Park Campus, Watford Road, Harrow, Mid-
dlesex, HA1 3UJ, UK (e-mail: a.stagg@imperial.ac.uk).
Copyright © 2004 by Lippincott Williams & Wilkins
496 Inflamm Bowel Dis • Volume 10, Number 5, September 2004