Tropheryma whippelii DNA Is Rare in the Intestines of Patients without Other Signs of Whipple Disease

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The summary below is from the full report titled " Tropheryma whippelii DNA Is Rare in the Intestinal Mucosa of Patients without Other Evidence of Whipple Disease." It is in the 16 January 2001 issue of Annals of Internal Medicine (volume 134, pages 115-119). The authors are M Maiwald, A von Herbay, DH Persing, PS Mitchell, MF Abdelmalek, JN Thorvilson, DN Fredricks, and DA Relman.

What is the problem and what is known about it so far?

Whipple disease is a rare condition that causes diarrhea, abdominal pain, difficulty in absorbing nutrients from food, weight loss, joint pain, swollen lymph nodes, and, in some cases, abnormalities of the nervous system. Whipple disease is thought to be caused by bacteria called Tropheryma whippelii (T. whippelii), which have been found in the tissue samples (particularly from the intestinal lining) of persons who have Whipple disease. Little is known about where these bacteria usually live or how people become infected with the bacteria and develop Whipple disease. Two recent studies reported that T. whippelii was found in persons without Whipple disease, but other studies have found no evidence of the bacteria in persons without the disease. These conflicting reports make it difficult for physicians to know what it means when T. whippelii is found in the tissues of patients.

Why did the researchers do this particular study?

To see whether T. whippelii bacteria are present in persons who do not have the usual features of Whipple disease.

Who was studied?

The study included 342 patients from three medical centers (two in the United States, one in Germany) who had biopsy samples of the intestinal lining obtained during a medical evaluation for abdominal pain or possible stomach ulcer (group A), symptoms of abnormal absorption of nutrients (group B), or suspected Whipple disease (group C). The patients in group C were included in the study only if they turned out not to have abnormalities typical of Whipple disease on microscopic examination of their intestinal tissue.

How was the study done?

The researchers examined all of the biopsy samples by using polymerase chain reaction (PCR), a test that provides a very sensitive way to look for genetic material of T. whippelii. Biopsy samples were also examined under the microscope for evidence of the bacteria.

What did the researchers find?

None of the intestinal biopsy samples showed evidence of T. whippelii bacteria using traditional methods with a microscope, and none of the PCR tests for the genetic material of the bacteria were positive.

What were the limitations of the study?

Only small sections of the patients' intestinal lining were tested, so it is possible that the bacteria could have been present in other parts of the intestine that were not examined.

What are the implications of the study?

Tropheryma whippelii does not appear to be present in the intestines of people who do not have Whipple disease.