- Email: [email protected]
Non-eosinophilic cor ticosteroid unresponsive asthma
RESEARCH LETTERS
Patient number
Age at diagnosis
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
6 months 2 years 3 months 4 years 6 months 5 years 2 months 5 years 4 months 5 years 11 months 6 years 4 months 6 years 5 months 6 years 9 months 7 years 10 years 2 months 11 years 12 years 2 months 13 years 8 months 15 years 10 months 17 years 3 months
Sex
M M M M M M F M F M M F M M M M
Age at GHI
3 years 9 years 1 month 4 years 6 months 8 years 3 months — — 13 years 6 years 5 months — 13 years 10 years 2 months 11 years — — 6 years —
Age at ACTH deficiency — — 4 years 6 months — — — 25 years 6 months — — — — — — — 6 years —
Age at TSH deficiency — — — — — — 25 years 6 months — — — — — — — 6 years —
Age at gonadotropin deficiency
CT/MRI scan findings (except absent PPBS)
NT — NT NT — NT 20 years 6 years 5 months NT 13 years — 11 years — — — —
Normal Normal Normal Normal Normal Normal Pituitary germinoma Small pituitary—normal Normal Suprasellar germinoma Small pituitary—normal Suprasellar germinoma Small pituitary—normal Normal Normal Normal
Duration of follow-up 3 years 5 months 11 years 5 months 3 years 9 months 9 years 10 months 14 years 11 months 8 years 8 months 20 years 14 years 10 months 3 years 1 month 12 years 14 years 8 months 18 years 1 year 6 months 4 years 8 months 6 years 4 months 5 years 6 months
PPBS=posterior pituitary bright spot; NT=not tested; M=male; F=female.
Endocrine evaluation at presentation and during follow-up period
patients with GHI as the only anterior pituitary endocrinopathy to accompany CDI (1, 2, 4, 11) also remained stable with normal brain scans; of the six patients with evolving anterior pituitary endocrinopathy other than GHI, four had documented gonadotropin deficiency and three had pituitary/suprasellar germinoma (7, 10, 12). Follow-up extended beyond puberty in 13 of our patients. Idiopathic CDI warrants regular follow-up, especially if anterior pituitary hormone deficiencies are detected. When other anterior pituitary endocrinopathies evolve in addition to GHI, particularly gonadotropin deficiency, there is a greater likelihood that a structural lesion of the hypothalamicpituitary axis is present. We thank our colleagues in the London Centre for Paediatric Endocrinology and the Department of Adult Endocrinology at the Middlesex Hospital for permission to examine the case records of their patients. 1
Sherwood MC, Stanhope RG, Preece MA, Grant DB. Diabetes insipdus and occult intracranial tumours. Arch Dis Child 1986; 61: 1222–35. 2 Stanhope RG, Preece MA, Grant DB, Brook CGD. Is diabetes insipidus during childhood ever idiopathic? Br J Hosp Med 1989; 41: 490–91. 3 Mootha SL, Barkovich AJ, Grumbach MM, et al. Idiopathic hypothalamic diabetes insipidus, pituitary stalk thickening, and the occult intracranial germinoma in children and adolescents. J Clin Endocrinol Metab 1997; 82: 1362–67. 4 Sclar CA, Grumbach MM, Kaplan SL, Conte FA. Hormonal and metabolic abnormalities associated with central nervous system germinoma in children and adolescents and the effect of therapy: report of 10 patients. J Clin Endocrinol Metab 1981; 52: 9–16. 5 Czernichow P, Pomarede R, Basmaciogullari A, Brauner R, Rappaport R. Diabetes insipidus in children. III. Anterior pituitary dysfunction in idopathic types. J Paediatr 1985; 106: 41–44. London Centre for Paediatric Endocrinology, University College London, London W1N 8AA, UK (E Charmandari)
Non-eosinophilic cor ticosteroid unresponsive asthma Ian D Pavord, Chris E Brightling, Gerrit Woltmann, Andrew J Wardlaw
Asthma is typically associated with sputum evidence of an eosinophilic bronchitis, although 10–20% of patients with symptomatic asthma have a sputum eosinophil count within the normal range. 1,2 Since the beneficial effects of corticosteroids in asthma are thought to be mediated through a reduction in eosinophilic airway inflammation, we postulated that non-eosinophilic asthma might be associated with a poor response to corticosteroids. We have tested this
THE LANCET • Vol 353 • June 26, 1999
hypothesis in 23 patients with asthma treated with asrequired 2-agonists studied before and 2 months after starting treatment with budesonide 400 g twice daily inhaled via a turbohaler. Patients had less than a five-packyear smoking history, clinical features suggesting asthma, and objective evidence of variable airflow obstruction. We measured spirometry, methacholine provocation concentration causing a 20% fall in FEV 1 (PC20) with the tidal breathing method,3 symptoms scores with a 10 cm visual analogue score (VAS), and induced sputum-eosinophil differential cell count with standard methods1,2 before and 12 h after the last dose of budesonide. Peak expiratory flow amplitude percent mean (PEF A%M) was derived from the maximum within-day PEF variability over a 2-week period before the start of treatment and the final 2 weeks of treatment. Laboratory assessments were done blind to clinical characteristics and treatment. Patients were divided into those with and without a sputum eosinophilia (sputum differential eosinophil count ⭓3%) based on their sputum eosinophil differential count before the start of treatment. We chose 3% as a cut off since it is over two SDs outside the normal range1,2 and has previously been shown to identify individuals with corticosteroid-responsive chronic obstructive pulmonary disease.4 The eosinophilic and non-eosinophilic groups had similar mean baseline FEV1 % predicted (86·2% and 81·3%), FEV1/FVC ratio (0·74 and 0·69), symptom VAS (46·9 mm and 43·8 mm), and PEF A%M (19·2% and 20·5%). The geometric mean baseline PC20 was less (0·8 mg/mL and 1·6 mg/mL; mean difference one doubling dose, 95% CI ⫺1 to 2·9; p=0·3) and sputum eosinophil differential cell count significantly higher (11·0% and 0·7%; mean difference 16·4 fold; 95% CI 6–44·4; p<0·001) in the eosinophilic group. Non-eosinophilic patients were less likely to be atopic and more likely to be current smokers (table). The mean posttreatment change in all measures was greater in the
Number Age (years) Male Atopy Current smoker ⌬FEV1 (mL) ⌬Symptom VAS (mm) ⌬PEF amplitude % mean ⌬PC20 (doubling doses) Decrease sputum eos (fold)
Eos <3%
Eos ⭓3%
9 53 5 2 3 100 (⫺193 to 394) ⫺0·7 (15·4 to ⫺16·8) ⫺3·2 (4·3 to ⫺10·7) 0 (⫺1·2 to 1·2) 1·6 (0·98 to 2·7)
14 45 11 8 1 142 (⫺5 to 289) ⫺24·4 (⫺12·5 to ⫺36·3) ⫺7·0 (⫺2·5 to ⫺11·6) 2·1 (1·3 to 3·0) 7·1 (3·7 to 13·5)
Patient details with mean (95% CI) change in measures after treatment with budesonide in those stratified according to sputum eosinophil (eos) count
2213
RESEARCH LETTERS
eosinophilic group. The increase in PC20 and decrease in sputum differential eosinophil count and symptom VAS were significant (table). There was a significant positive correlation between the log baseline sputum eosinophil differential count and the doubling dose change in PC 20 following treatment (Pearson’s correlation coefficient 0·41; p<0·05). We have shown that non-eosinophilic asthma is associated wtih a poor response to inhaled corticosteroids. MorrowBrown has reported similar findings in patents with chronic bronchospasm treated with oral prednisolone, although the methods used to assess the response to treatment and sputum eosinophilia were largely subjective.5 We have not examined the reasons why patients with symptomatic asthma do not have a sputum eosinophilia, but it is possible that some had alternative explanations for their asthma-like symptoms and disordered airway function such as chronic bronchitis or mild bronchiectasis. Symptoms may also be caused by airway remodelling secondary to previously active eosinophilic-airway inflammation, and residual airway hyperresponsiveness. Our study was small, uncontrolled, and examined the short-term effects of treatment, so we cannot exclude a minor beneficial effect of treatment or a long-term benefit, nor can we be confident about the accuracy of a sputum eosinophil count of 3% as a cut-off for corticosteroid-responsive disease. However, our findings do raise the possibility that the sputum eosinophil count is an important determinant of the response to corticosteroids in asthma. Larger, longer, placebo-controlled studies may allow us to identify a subgroup who do not benefit from corticosteroid treatment and might lead to more rational and economical use of these drugs in asthma. Supported by grants from Glenfield Hospital Research Fund and Astra Charwood. We thank Richard Ward, Debbie Parker, Will Monterio, and the staff in the lung function department for help with the laboratory measurements. 1
2
3
4
5
Pavord ID, Pizzichini MMM, Pizzichini E, Hargreave FE. The use of induced sputum to investigate airway inflammation. Thorax 1997; 52: 498–501. Pizzichini E, Pizzichini MMM, Efthimiadis A, et al. Indices of airway inflammation in induced sputum: reproducibility and validity of cell and fluid phase measurements. Am J Respir Crit Care Med 1996; 154: 308–17. Juniper EF, Cockcroft DW, Hargreave FE. Histamine and methacholine inhalation tests: a laboratory tidal breathing protocol, 2nd edn. Lund, Sweden: Astra Draco, AB, 1994. Pizzichini E, Pizzichini MMM, Gibson P, et al. Sputum eosinophilia predicts benefit from prednisolone in smokers with chronic bronchitis. Am J Respir Crit Care Med 1998; 158: 1511–17. Morrow Brown H. Treatment of chronic asthma with prednisolone. Signifiance of eosinophils in the sputum. Lancet 1958; ii: 1245–47.
Department of Respiratory Medicine and Thoracic Surgery, Glenfield Hospital, Leicester LE3 9QP, UK (I D Pavord)
PCR-positive tests for Tropheryma whippelii in patients without Whipple’s disease Hans-Ulrich Ehrbar, Peter Bauerfeind, Fabrizio Dutly, Hans-Rudolf Koelz, Martin Altwegg
The diagnosis of Whipple’s disease depends largely on laboratory investigations such as finding Periodic Acid Schiff (PAS)-positive, rod-shaped structures in macrophages of duodenal biopsy samples and in other tissues and/or the presence of bacteria with a typical trilamellar membrane by electron microscopy. The causative non-cultivable agent, Tropheryma whippelii (TW), has recently been characterised by molecular methods based on the 16S-rRNA gene sequence.1 The 16S-rRNA gene has been used as target for
2214
TW-PCR positive (of 105 patients) Duodenal biopsy samples Gastric juice Total
5 (4·8%) 12 (11·4%) 14 *(13·3%)
*Three patients were positive in both duodenal biopsy samples and gastric juice.
Results of TW-PCR
diagnostic PCR, 2–5 suggesting a higher sensitivity of PCR as compared with histology. Because the diagnosis of Whipple’s disease has major implications for the patient, such as longterm antibiotic treatment, the specificity of this test is crucial. However, only one study has tested the specificity of TW-PCR with biopsy samples from the colon in a small number of patients.3 We investigated 105 patients (60 men, aged 20–80 years) referred for elective gastroscopy without clinical signs of Whipple’s disease. The study was approved by the ethics committee of the University of Zurich, and informed consent was obtained from all participants. Biopsy samples from the duodenum were taken for histology, electron microscopy, and TW-PCR analysis. Gastric juice was also taken for TWPCR. For TW-PCR, the primer combination TW-1/TW-3, corresponding to primers W3FE/W4RB of Rickman and colleagues2 was used. All positive specimens were also analysed with primers TW-1/TW-2 identical to pW2RB followed by semi-nested reamplification with primers TW4/TW-2.5 DNA extracted from the heart valve of a patient with confirmed T whippelii endocarditis was used as positive control. PCR was considered positive if both PCR tests were positive. TW-PCR was positive in duodenal biopsy samples of five patients (4·8%) and in the gastric juice of 12 (11·4%) (table). In three of these patients, TW-PCR was positive in both specimens. PCR results were confirmed by analysing a second biopsy specimen of all 14 PCR-positive and in 24 PCR-negative patients. The sequences of all amplified TW4/TW-2 fragments were identical to the published T whippelii 16S-rRNA reference sequence. The specificity of TW-PCR as compared with a gold standard defined by histology and clinical signs was 95·2% (95% CI: 88·9–98·4%) and 88·6% (81·9–94·1%) for duodenal biopsy samples and gastric juice, respectively. This study shows a high rate of positive TW-PCR in duodenal biopsy samples and gastric juice of patients without other evidence of Whipple’s disease. The reason for this is unclear. We speculate that T whippelii or closely related bacteria are present in a substantial fraction of the population in the absence of Whipple’s disease. Bacterial or host factors may be necessary for the development of Whipple’s disease. We conclude that treatment of suspected Whipple’s disease should not be based on positive PCR findings alone. We thank T Breitbach and M Spycher for histology and electron microscopy. Supported by Swiss National Science Foundation grants 3200-045998.95 and 3200-50790.97/1. 1
Relman DA, Schmidt TM, Mac Dermott RP, Falkow S. Identification of the uncultured bacillus of Whipple’s disease. N Engl J Med 1992; 327: 293–301. 2 Rickman LS, Freeman WS, Green WR, et al. Uveitis caused by Tropheryma whippelii (Whipple’s bacillus). N Engl J Med 1995; 322: 363–66. 3 Ramzan NN, Loftus E Jr, Burgart LJ, et al. Diagnosis and monitoring of Whipple’s disease by polymerase chain reaction. Ann Intern Med 1997; 126: 520–27. 4 Von Herbay A, Ditton HJ, Maiwald M. Diagnostic application of a polymerase chain reaction assay for Whipple’s disease bacterium to intestinal biopsies. Gastroenterology 1996; 110: 1735–43. 5 Brändle M, Ammann P, Dutly F, Schmid C, Altwegg M. Relapsing Whipple’s disease presenting with hypopituitarism. Clin Endocrinol (in press). Division of Gastroenterology and Department of Medical Microbiology, University of Zurich, and Division of Gastroenterology, Treimli Hospital, CH-8091 Zurich, Switzerland (P Bauerfeind e-mail: [email protected])
THE LANCET • Vol 353 • June 26, 1999
Patient number
Age at diagnosis
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
6 months 2 years 3 months 4 years 6 months 5 years 2 months 5 years 4 months 5 years 11 months 6 years 4 months 6 years 5 months 6 years 9 months 7 years 10 years 2 months 11 years 12 years 2 months 13 years 8 months 15 years 10 months 17 years 3 months
Sex
M M M M M M F M F M M F M M M M
Age at GHI
3 years 9 years 1 month 4 years 6 months 8 years 3 months — — 13 years 6 years 5 months — 13 years 10 years 2 months 11 years — — 6 years —
Age at ACTH deficiency — — 4 years 6 months — — — 25 years 6 months — — — — — — — 6 years —
Age at TSH deficiency — — — — — — 25 years 6 months — — — — — — — 6 years —
Age at gonadotropin deficiency
CT/MRI scan findings (except absent PPBS)
NT — NT NT — NT 20 years 6 years 5 months NT 13 years — 11 years — — — —
Normal Normal Normal Normal Normal Normal Pituitary germinoma Small pituitary—normal Normal Suprasellar germinoma Small pituitary—normal Suprasellar germinoma Small pituitary—normal Normal Normal Normal
Duration of follow-up 3 years 5 months 11 years 5 months 3 years 9 months 9 years 10 months 14 years 11 months 8 years 8 months 20 years 14 years 10 months 3 years 1 month 12 years 14 years 8 months 18 years 1 year 6 months 4 years 8 months 6 years 4 months 5 years 6 months
PPBS=posterior pituitary bright spot; NT=not tested; M=male; F=female.
Endocrine evaluation at presentation and during follow-up period
patients with GHI as the only anterior pituitary endocrinopathy to accompany CDI (1, 2, 4, 11) also remained stable with normal brain scans; of the six patients with evolving anterior pituitary endocrinopathy other than GHI, four had documented gonadotropin deficiency and three had pituitary/suprasellar germinoma (7, 10, 12). Follow-up extended beyond puberty in 13 of our patients. Idiopathic CDI warrants regular follow-up, especially if anterior pituitary hormone deficiencies are detected. When other anterior pituitary endocrinopathies evolve in addition to GHI, particularly gonadotropin deficiency, there is a greater likelihood that a structural lesion of the hypothalamicpituitary axis is present. We thank our colleagues in the London Centre for Paediatric Endocrinology and the Department of Adult Endocrinology at the Middlesex Hospital for permission to examine the case records of their patients. 1
Sherwood MC, Stanhope RG, Preece MA, Grant DB. Diabetes insipdus and occult intracranial tumours. Arch Dis Child 1986; 61: 1222–35. 2 Stanhope RG, Preece MA, Grant DB, Brook CGD. Is diabetes insipidus during childhood ever idiopathic? Br J Hosp Med 1989; 41: 490–91. 3 Mootha SL, Barkovich AJ, Grumbach MM, et al. Idiopathic hypothalamic diabetes insipidus, pituitary stalk thickening, and the occult intracranial germinoma in children and adolescents. J Clin Endocrinol Metab 1997; 82: 1362–67. 4 Sclar CA, Grumbach MM, Kaplan SL, Conte FA. Hormonal and metabolic abnormalities associated with central nervous system germinoma in children and adolescents and the effect of therapy: report of 10 patients. J Clin Endocrinol Metab 1981; 52: 9–16. 5 Czernichow P, Pomarede R, Basmaciogullari A, Brauner R, Rappaport R. Diabetes insipidus in children. III. Anterior pituitary dysfunction in idopathic types. J Paediatr 1985; 106: 41–44. London Centre for Paediatric Endocrinology, University College London, London W1N 8AA, UK (E Charmandari)
Non-eosinophilic cor ticosteroid unresponsive asthma Ian D Pavord, Chris E Brightling, Gerrit Woltmann, Andrew J Wardlaw
Asthma is typically associated with sputum evidence of an eosinophilic bronchitis, although 10–20% of patients with symptomatic asthma have a sputum eosinophil count within the normal range. 1,2 Since the beneficial effects of corticosteroids in asthma are thought to be mediated through a reduction in eosinophilic airway inflammation, we postulated that non-eosinophilic asthma might be associated with a poor response to corticosteroids. We have tested this
THE LANCET • Vol 353 • June 26, 1999
hypothesis in 23 patients with asthma treated with asrequired 2-agonists studied before and 2 months after starting treatment with budesonide 400 g twice daily inhaled via a turbohaler. Patients had less than a five-packyear smoking history, clinical features suggesting asthma, and objective evidence of variable airflow obstruction. We measured spirometry, methacholine provocation concentration causing a 20% fall in FEV 1 (PC20) with the tidal breathing method,3 symptoms scores with a 10 cm visual analogue score (VAS), and induced sputum-eosinophil differential cell count with standard methods1,2 before and 12 h after the last dose of budesonide. Peak expiratory flow amplitude percent mean (PEF A%M) was derived from the maximum within-day PEF variability over a 2-week period before the start of treatment and the final 2 weeks of treatment. Laboratory assessments were done blind to clinical characteristics and treatment. Patients were divided into those with and without a sputum eosinophilia (sputum differential eosinophil count ⭓3%) based on their sputum eosinophil differential count before the start of treatment. We chose 3% as a cut off since it is over two SDs outside the normal range1,2 and has previously been shown to identify individuals with corticosteroid-responsive chronic obstructive pulmonary disease.4 The eosinophilic and non-eosinophilic groups had similar mean baseline FEV1 % predicted (86·2% and 81·3%), FEV1/FVC ratio (0·74 and 0·69), symptom VAS (46·9 mm and 43·8 mm), and PEF A%M (19·2% and 20·5%). The geometric mean baseline PC20 was less (0·8 mg/mL and 1·6 mg/mL; mean difference one doubling dose, 95% CI ⫺1 to 2·9; p=0·3) and sputum eosinophil differential cell count significantly higher (11·0% and 0·7%; mean difference 16·4 fold; 95% CI 6–44·4; p<0·001) in the eosinophilic group. Non-eosinophilic patients were less likely to be atopic and more likely to be current smokers (table). The mean posttreatment change in all measures was greater in the
Number Age (years) Male Atopy Current smoker ⌬FEV1 (mL) ⌬Symptom VAS (mm) ⌬PEF amplitude % mean ⌬PC20 (doubling doses) Decrease sputum eos (fold)
Eos <3%
Eos ⭓3%
9 53 5 2 3 100 (⫺193 to 394) ⫺0·7 (15·4 to ⫺16·8) ⫺3·2 (4·3 to ⫺10·7) 0 (⫺1·2 to 1·2) 1·6 (0·98 to 2·7)
14 45 11 8 1 142 (⫺5 to 289) ⫺24·4 (⫺12·5 to ⫺36·3) ⫺7·0 (⫺2·5 to ⫺11·6) 2·1 (1·3 to 3·0) 7·1 (3·7 to 13·5)
Patient details with mean (95% CI) change in measures after treatment with budesonide in those stratified according to sputum eosinophil (eos) count
2213
RESEARCH LETTERS
eosinophilic group. The increase in PC20 and decrease in sputum differential eosinophil count and symptom VAS were significant (table). There was a significant positive correlation between the log baseline sputum eosinophil differential count and the doubling dose change in PC 20 following treatment (Pearson’s correlation coefficient 0·41; p<0·05). We have shown that non-eosinophilic asthma is associated wtih a poor response to inhaled corticosteroids. MorrowBrown has reported similar findings in patents with chronic bronchospasm treated with oral prednisolone, although the methods used to assess the response to treatment and sputum eosinophilia were largely subjective.5 We have not examined the reasons why patients with symptomatic asthma do not have a sputum eosinophilia, but it is possible that some had alternative explanations for their asthma-like symptoms and disordered airway function such as chronic bronchitis or mild bronchiectasis. Symptoms may also be caused by airway remodelling secondary to previously active eosinophilic-airway inflammation, and residual airway hyperresponsiveness. Our study was small, uncontrolled, and examined the short-term effects of treatment, so we cannot exclude a minor beneficial effect of treatment or a long-term benefit, nor can we be confident about the accuracy of a sputum eosinophil count of 3% as a cut-off for corticosteroid-responsive disease. However, our findings do raise the possibility that the sputum eosinophil count is an important determinant of the response to corticosteroids in asthma. Larger, longer, placebo-controlled studies may allow us to identify a subgroup who do not benefit from corticosteroid treatment and might lead to more rational and economical use of these drugs in asthma. Supported by grants from Glenfield Hospital Research Fund and Astra Charwood. We thank Richard Ward, Debbie Parker, Will Monterio, and the staff in the lung function department for help with the laboratory measurements. 1
2
3
4
5
Pavord ID, Pizzichini MMM, Pizzichini E, Hargreave FE. The use of induced sputum to investigate airway inflammation. Thorax 1997; 52: 498–501. Pizzichini E, Pizzichini MMM, Efthimiadis A, et al. Indices of airway inflammation in induced sputum: reproducibility and validity of cell and fluid phase measurements. Am J Respir Crit Care Med 1996; 154: 308–17. Juniper EF, Cockcroft DW, Hargreave FE. Histamine and methacholine inhalation tests: a laboratory tidal breathing protocol, 2nd edn. Lund, Sweden: Astra Draco, AB, 1994. Pizzichini E, Pizzichini MMM, Gibson P, et al. Sputum eosinophilia predicts benefit from prednisolone in smokers with chronic bronchitis. Am J Respir Crit Care Med 1998; 158: 1511–17. Morrow Brown H. Treatment of chronic asthma with prednisolone. Signifiance of eosinophils in the sputum. Lancet 1958; ii: 1245–47.
Department of Respiratory Medicine and Thoracic Surgery, Glenfield Hospital, Leicester LE3 9QP, UK (I D Pavord)
PCR-positive tests for Tropheryma whippelii in patients without Whipple’s disease Hans-Ulrich Ehrbar, Peter Bauerfeind, Fabrizio Dutly, Hans-Rudolf Koelz, Martin Altwegg
The diagnosis of Whipple’s disease depends largely on laboratory investigations such as finding Periodic Acid Schiff (PAS)-positive, rod-shaped structures in macrophages of duodenal biopsy samples and in other tissues and/or the presence of bacteria with a typical trilamellar membrane by electron microscopy. The causative non-cultivable agent, Tropheryma whippelii (TW), has recently been characterised by molecular methods based on the 16S-rRNA gene sequence.1 The 16S-rRNA gene has been used as target for
2214
TW-PCR positive (of 105 patients) Duodenal biopsy samples Gastric juice Total
5 (4·8%) 12 (11·4%) 14 *(13·3%)
*Three patients were positive in both duodenal biopsy samples and gastric juice.
Results of TW-PCR
diagnostic PCR, 2–5 suggesting a higher sensitivity of PCR as compared with histology. Because the diagnosis of Whipple’s disease has major implications for the patient, such as longterm antibiotic treatment, the specificity of this test is crucial. However, only one study has tested the specificity of TW-PCR with biopsy samples from the colon in a small number of patients.3 We investigated 105 patients (60 men, aged 20–80 years) referred for elective gastroscopy without clinical signs of Whipple’s disease. The study was approved by the ethics committee of the University of Zurich, and informed consent was obtained from all participants. Biopsy samples from the duodenum were taken for histology, electron microscopy, and TW-PCR analysis. Gastric juice was also taken for TWPCR. For TW-PCR, the primer combination TW-1/TW-3, corresponding to primers W3FE/W4RB of Rickman and colleagues2 was used. All positive specimens were also analysed with primers TW-1/TW-2 identical to pW2RB followed by semi-nested reamplification with primers TW4/TW-2.5 DNA extracted from the heart valve of a patient with confirmed T whippelii endocarditis was used as positive control. PCR was considered positive if both PCR tests were positive. TW-PCR was positive in duodenal biopsy samples of five patients (4·8%) and in the gastric juice of 12 (11·4%) (table). In three of these patients, TW-PCR was positive in both specimens. PCR results were confirmed by analysing a second biopsy specimen of all 14 PCR-positive and in 24 PCR-negative patients. The sequences of all amplified TW4/TW-2 fragments were identical to the published T whippelii 16S-rRNA reference sequence. The specificity of TW-PCR as compared with a gold standard defined by histology and clinical signs was 95·2% (95% CI: 88·9–98·4%) and 88·6% (81·9–94·1%) for duodenal biopsy samples and gastric juice, respectively. This study shows a high rate of positive TW-PCR in duodenal biopsy samples and gastric juice of patients without other evidence of Whipple’s disease. The reason for this is unclear. We speculate that T whippelii or closely related bacteria are present in a substantial fraction of the population in the absence of Whipple’s disease. Bacterial or host factors may be necessary for the development of Whipple’s disease. We conclude that treatment of suspected Whipple’s disease should not be based on positive PCR findings alone. We thank T Breitbach and M Spycher for histology and electron microscopy. Supported by Swiss National Science Foundation grants 3200-045998.95 and 3200-50790.97/1. 1
Relman DA, Schmidt TM, Mac Dermott RP, Falkow S. Identification of the uncultured bacillus of Whipple’s disease. N Engl J Med 1992; 327: 293–301. 2 Rickman LS, Freeman WS, Green WR, et al. Uveitis caused by Tropheryma whippelii (Whipple’s bacillus). N Engl J Med 1995; 322: 363–66. 3 Ramzan NN, Loftus E Jr, Burgart LJ, et al. Diagnosis and monitoring of Whipple’s disease by polymerase chain reaction. Ann Intern Med 1997; 126: 520–27. 4 Von Herbay A, Ditton HJ, Maiwald M. Diagnostic application of a polymerase chain reaction assay for Whipple’s disease bacterium to intestinal biopsies. Gastroenterology 1996; 110: 1735–43. 5 Brändle M, Ammann P, Dutly F, Schmid C, Altwegg M. Relapsing Whipple’s disease presenting with hypopituitarism. Clin Endocrinol (in press). Division of Gastroenterology and Department of Medical Microbiology, University of Zurich, and Division of Gastroenterology, Treimli Hospital, CH-8091 Zurich, Switzerland (P Bauerfeind e-mail: [email protected])
THE LANCET • Vol 353 • June 26, 1999