Aliment Pharmacol Ther 2010; 32: 1392–1397
Background Lymphocytic duodenosis is defined by normal villous architecture and intraepithelial lymphocytes (IELs) >25 per 100 enterocytes. Such patients should not be diagnosed with coeliac disease, solely by histology, as previous retrospective studies have suggested other associations with lymphocytic duodenosis.
Aim To study prospectively the aetiology of lymphocytic duodenosis.
Methods One hundred patients with lymphocytic duodenosis were investigated rigorously for coeliac disease and other known associations for lymphocytic duodenosis by initial investigations of coeliac serology, and exclusion of infection. Of 34 with no explanation for lymphocytic duodenosis, 29 underwent repeat duodenal biopsies following a gluten challenge.
Results Coeliac disease was present in 16% of patients with lymphocytic duodenosis. In the absence of a positive coeliac diagnosis, lymphocytic duodenosis was most commonly associated with drugs (21%), infection (19%), immune dysregulation (4%), inflammatory bowel disease (2%), microscopic colitis (2%), sarcoidosis (1%) and IgA deficiency (1%). Of 34 with no known associations, 18 had symptoms of irritable bowel syndrome (IBS), and in 29 patients investigated with repeat duodenal biopsies, the IEL count returned to normal in 22.
Conclusions In 66% of cases of lymphocytic duodenosis, a known association can be found by further investigations; importantly, 16% will have coeliac disease. In those with no apparent cause, there may be an association with IBS and the IEL count becomes normal on repeat biopsy in 76%.
Duodenal intraepithelial lymphocytes (IELs) are involved in intestinal immune surveillance and activation, with levels increasing in response to antigenic stress.1, 2
The normal IEL count was initially established in 1971 to be <40 IELs per 100 enterocytes. This figure was determined from jejunal biopsies using a Crosby or Watson capsule, with counts being performed on 7-μm-thick sections.3 However, more recently, the normal IEL count has been revised to <25 IELs per 100 enterocytes. This is through duodenal biopsies being obtained endoscopically with histology performed on sections cut at 3–4 μm.4, 5
Lymphocytic duodenosis (LD) is now defined by normal villous architecture and >25 IELs per 100 enterocytes.4, 6 Some investigators may call this Marsh grade 1 (if suspicious of coeliac disease). LD is found in approximately 2–3.8% of duodenal biopsies.6–8
A few retrospective studies have identified the causes of LD, which include coeliac disease,9, 10 gastrointestinal infections,11, 12 immunological disorders,9, 13 nonsteroidal anti-inflammatory drugs (NSAID),9, 14 inflammatory bowel disease (IBD),15 IgA deficiency16 and more recently Helicobacter pylori.17, 18 Vande Voort et al. undertook a retrospective review of 124 patients with LD.19 The investigators described features which would help to discriminate patients with LD who had underlying coeliac disease from those who did not, for example, the presence or absence of HLA DQ2 or DQ8. However, they did not systematically investigate these patients for other causes of LD.
Over the last decade, studies have focused mainly on evaluating patients with LD that belong to the spectrum of coeliac disease. Recognition of coeliac disease, even at this early stage, is important, as these patients may have already developed symptoms and complications, such as anaemia and osteoporosis, which can improve on a gluten-free diet (GFD).10 Equally, excluding coeliac disease will prevent inappropriate prescription of a potentially expensive and socially inhibiting GFD, and instead allows recognition and treatment of any other underlying cause.
Methods of identifying those patients with LD that belong to the spectrum of coeliac disease include revisiting the patient’s history and investigations as well as demonstrating histological deterioration on gluten. Enquiring specifically in the history about autoimmune disorders, such as Graves disease, is important due to the association with coeliac disease.20, 21 However, conditions such as thyroid disease, rheumatoid arthritis, psoriasis and connective tissue disorders can cause raised duodenal IEL counts independently through a process of immune dysregulation9, 13– this could be viewed as a speculative opinion and further work is required to delineate this relationship. Moreover, dermatitis herpetiformis (DH), an itchy blistering rash, is almost always associated with coeliac disease,22 with up to 50% of patients demonstrating only subtle mucosal changes on duodenal biopsy.23, 24 Finally, in first-degree relatives of those with coeliac disease, the risk of developing gluten-sensitive enteropathy is 5–10%.25, 26
Investigations to support the diagnosis of coeliac disease should involve testing for tissue transglutaminase antibody (tTG) and/or endomysial antibody (EMA) in the presence of a normal IgA level.27 However, patients with LD with possible/potential coeliac disease may present with a negative EMA, as the prevalence of a positive EMA strongly correlates with the severity of mucosal damage.28
For cases where the diagnosis is uncertain (such as in patients with LD), there may be a role for human leucocyte antigen (HLA) typing27– HLA DQ2 or DQ8 are closely linked with coeliac disease, occurring in up to 98% of cases,29 but they are also present in 25% of the normal population.30 An absence of these haplotypes can therefore be used as a negative predictive test. Approximately 50% of patients with LD have been shown to be negative for HLA DQ2 or DQ8, thus not belonging to the spectrum of coeliac disease.19 HLA typing is expensive and should be reserved for equivocal cases. If the serology is negative and you still strongly suspect coeliac disease, HLA typing can help, but it is not a first-line investigation.
A recent Finnish study has shown that patients with LD who have both a positive EMA and HLA to belong to the spectrum of coeliac disease. The investigators randomized these patients to either a gluten-containing diet (n = 10) or GFD (n = 13), and found progressive clinical, biochemical and histological deterioration in all those randomized to a gluten-containing diet. Furthermore, these individuals improved all parameters when they were commenced on a GFD, after the initial study period.31
A gluten challenge can also be useful in causing further mucosal deterioration in those patients with potential coeliac disease in whom the initial small intestinal biopsies reveal only minor abnormalities.32 However, an initial trial response to a GFD is not as helpful, as up to 38% of patients with LD who have had a favourable response to a GFD are negative for the DQ2 or DQ8 haplotypes.19
Despite the numerous possible causes of LD, it has been noted by other investigators that patients may be given a diagnosis of coeliac disease solely on the presence of duodenal intraepithelial lymphocytosis.33 For these reasons, the aim of our study was to develop a systematic approach to diagnose the underlying causes of LD and treat patients effectively.
The study was conducted between February 2003 and February 2010 at the Royal Hallamshire Hospital in Sheffield, a tertiary care centre for gastroenterology. One hundred patients with LD (>25 IELs per 100 enterocytes) were sequentially identified and investigated to determine a cause for their raised IELs. All patients who were identified agreed to participate. The study was registered with both South Sheffield local ethics and audit committees.
Patients then underwent a two-step process for identification of the underlying cause of their LD. Step 1 involved revisiting the patient’s history and investigations for diagnostic clues (Figure 1). In those where no cause was apparent/unclear or where coeliac disease was a possibility (including any patient with a positive HLA), patients then proceeded to step 2 (Figure 1). This involved a 6-week gluten challenge followed by repeat coeliac serology, duodenal biopsies and small bowel aspirate for microscopy, culture and sensitivity. If no previous H. pylori status was documented, then patients were questioned for symptoms at the time of their second biopsy and a CLO test was also performed.
A diagnosis of coeliac disease was made in those with positive serology (EMA or tTG), relevant symptoms and a HLA pattern of DQ2 or DQ8. These patients also had to have either progression of their LD to villous atrophy or a persistence of their LD. Finally, in these individuals, we also ensured that they had a symptomatic response to the GFD.
Statistical analyses of data were performed using spss. Differences between the groups were assessed using Fisher’s exact test.
Of the 100 patients investigated, 74 were women. The age range was from 16 to 83 years, with a median age of 47. The mean period of follow-up was 18 months (range 2–72).
To find an underlying cause, 88/100 patients had to be investigated using the two-step approach. In these 100 patients, an underlying cause for LD was found in 66 cases – principally drug-related (n = 21), coeliac disease (n = 16) and H. Pylori (n = 14). There were five cases of gastrointestinal infection: giardia, threadworms, campylobacter and two cases of small bowel bacterial overgrowth. There were four cases of autoimmune disease including systemic sclerosis, hypothyroidism, rheumatoid arthritis and primary biliary cirrhosis. There was one case of sarcoidosis. There were two cases of inflammatory bowel disease. Ulcerative colitis was diagnosed based on colonic biopsies, which revealed mucosal inflammation, and Crohn’s was based on the second duodenal biopsy revealing granulomatous changes. Detailed causes of LD are shown in Figure 2.
All cases of coeliac disease were positive for HLA DQ2 or DQ8, whereas 47/84 noncoeliac cases carried the DQ2 or DQ8 haplotypes, (P = 0.0004).
Despite an extensive work up, in 34 cases, we were unable to identify a cause for the LD. Of these, 29/34 patients were willing to undergo re-biopsy. In 22/29 patients, the IEL count was reduced to <25 per 100 enterocytes on the second biopsy, while seven had a persistently raised count with no apparent cause. When questioning these 34 patients, 18 had gastrointestinal symptoms consistent with a diagnosis of irritable bowel syndrome (IBS) using the ROME II Criteria.34
This is the first study to date investigating the causes of LD in a prospective and systematic manner.
In 66% of cases, an identifiable cause was found with drugs [NSAID or acetylsalicylic acid (ASA)], coeliac disease and H. pylori being the three most common causes. We are aware that a possible limitation of this study is that despite there being evidence supporting ASA-induced small bowel injury, there is no specific data regarding ASA and raised IELs. Nevertheless, a recent study administrating low-dose ASA over a short period noted its use to be associated with increased occurrence of small intestinal mucosal damage.35 This was determined with the use of video-capsule endoscopy, faecal calprotectin and intestinal permeability testing. These findings therefore suggest that ASA can induce small bowel inflammation and enteropathy and are supportive of our own observations.
The concept of immune dysregulation causing LD has been noted previously and is poorly understood, possibly even speculative.9, 13 Of the four cases in our study where LD was attributed to immune dysregulation, all went through step 2 to ensure that both coeliac disease and gastrointestinal infections were excluded.
In 34% of cases, a cause for LD was not found. However, the majority of these patients normalized their IEL counts on the 2nd set of duodenal biopsies. We speculate that this could be a postinfective picture (±IBS) and clinically would suggest reassurance in this group. In those with persistent LD, the long-term outcome is not yet clear and these patients remain under active follow-up. More than a half of the ‘no cause’ found group had symptoms consistent with a diagnosis of IBS. The significance and association of IELs and IBS are contentious. Studies have shown conflicting data, with reported IEL counts ranging from normal to slightly elevated.36–44 Suggested hypotheses include intraepithelial lymphocytosis being a marker of a luminal factor that triggers a low-grade inflammatory response or an immunological memory that persists after earlier antigenic provocations.43 It has been postulated that these cells may play a role in releasing mediators that evoke enteric nervous system responses, excite sensory afferent pathways and induce visceral hyperalgesia.44
In conclusion, in 66% of cases of LD, a known association can be found by further investigations; importantly 16% will have coeliac disease. HLA typing may have a role in differentiating between coeliac and noncoeliac cases.27 In those with no apparent cause, there may be an association with IBS and the IEL count became normal on repeat biopsy in 76%.
We wish to acknowledge the help of Professor TJ Stephenson, Dr SS Cross and Dr A Dube (Department of GI Histopathology, Royal Hallamshire Hospital, UK) who were all involved in the reporting and review of these cases. Declaration of personal and funding interests: None.