Frémont, de Meirleir en kollega's hebben m.b.v. de PCR-techniek

biopten van de maag en de twaalfvingerige darm (klik hier voor toelichting) onderzocht

van 48 CVS-patiënten en 35 gezonde (?) mensen met lichte maag-darm-klachten.

De resultaten van de bioptanalyse zijn in onderstaande tabel weergegeven.

Opmerkelijk:

• HHV-6 en EBV kwamen bij CVS-patiënten als bij gezonde (?) mensen

in soortgelijke aantallen en in vergelijkbare hoeveelheden voor.

• HHV-7 kwam bij vrijwel alle CVS-patiënten en kontrolepersonen voor:

er was een trend naar hogere koncentraties bij CVS-patiënten.

• HHV6 kán het immuunsysteem onderdrukken ten faveure van andere ziektekiemen.
• Een signifikant verschil was het aantal Parvo-positieve biopten (CVS 40%, anderen 14%).
• HHV6 en Parvo B19 werd niet in het bloed aangetroffen ondanks positieve biopten.
• EBV werd in 3 bloedmonsters aangetoond, terwijl 11 biopten positief waren.
• HHV-7 werd in 12 bloedmonsters gevonden.

Er was echter geen korrelatie met de aanwezigheid van HHV-7 in de biopten.

• Het spijsverteringskanaal is een reservoir/schuilplaats voor herpesvirussen.
De aanwezigheid van potentieel ziekmakende virussen in maag en darmen kán

bij een verzwakt/verstoord afweersysteem (CVS) leiden tot inflammatie/reaktivatie.

Enkele relevante citaten uit het uitgebreide studierapport:

One objective of this study was to investigate whether the presence of HHV-6, HHV-7 and/or EBV in the gastrointestinal tract could be associated with CFS. All three viruses could be detected in both gastric and intestinal biopsies. However, they could be detected at similar frequencies, and usually similar loads, in biopsies from both CFS patients and non-CFS controls.

Only in the case of HHV-7 could a possible trend towards higher loads be observed in the CFS samples compared to the controls, however the difference was not statistically significant. Higher loads of HHV-7 in CFS versus control samples, if confirmed, could be a consequence of impaired mucosal immunity rather than a real cause of the disease.

Regarding HHV-6 and EBV, no significant difference could be found between the CFS patients and the controls: the frequency of positive samples and the mean viral loads in these positive samples were similar in both populations. Therefore, the results do not seem to support an implication of these viruses in the pathogenesis of CFS.

This implication, however, cannot be totally excluded:

HHV-6 is known to induce a selective immune suppression which could have, in some of the positive patients, favored the development of other intracellular pathogens, viruses or mycobacteria (25).

Also, persistence of herpesviruses could cause a chronic inflammation of the gastro-intestinal tract, which could still, in certain predisposed people, contribute to the disease (chronic activation of immune function).

Nevertheless, the presence of these potentially pathogenic viruses in the gastro­intestinal tract of apparently healthy people is a clinically relevant observation. HHV-6, HHV-7 and EBV can reactivate and cause severe complications in immunocompromised patients (26, 27).

Obviously the gastrointestinal tract is a major reservoir from which herpesviruses could spread in case of impaired immunity.

A most important finding is the higher frequency of parvovirus B19 positive biopsies in the CFS population, compared to the controls (38-40% in CFS duodenum and stomach biopsies, versus less than 14% in the controls). This difference suggests that parvovirus B19 may be involved in the development and maintenance of CFS, at least for a subset of patients.

The gastro-intestinal tract has now been identified as a reservoir where parvovirus B19 may persist in the host following primary infection.

It is noteworthy that no viral DNA was detectable in the blood samples isolated from the same patients.

Persistence of parvovirus B19 infections in certain individuals may be determined by genetic factors (29), as well as by pre-existing immune dysfunction in the intestinal mucosa.

Detection of Herpesviruses and Parvovirus B19 in Gastric and Intestinal Mucosa of Chronic Fatigue Syndrome Patients

in vivo 23: 209-214 (2009)

Frémont M, Metzger K, Rady H, Hulstaert J, de Meirleir K.

Background:

Human herpesvirus-6 (HHV-6),

Epstein-Barr virus and

parvovirus B19

have been suggested as

etiological agents of chronic fatigue syndrome

but none of these viruses is consistently detected in all patients.

However,

active viral infections may be localized in specific tissues, and,

therefore, are not easily detectable.

The aim of this study was

to investigate the presence of HHV-6, HHV-7, EBV and parvovirus B19

in the gastro-intestinal tract

of CFS patients.

Patients and Methods:

Using real-time PCR,

viral DNA loads were quantified in

gastro-intestinal biopsies of

48 CFS patients and

35 controls.

Results:

High loads of HHV-7 DNA were detected in

most CFS and

control biopsies.

EBV and

HHV-6 were

detected in 15-30% of all biopsies.

Parvovirus B19 DNA was detected in

40% of the patients

versus less than 15% of the controls.

Conclusion:

Parvovirus B19 may be involved in the pathogenesis of CFS,

at least for a subset of patients.

The gastro-intestinal tract appears as

an important reservoir of infection

for several potentially pathogenic viruses.

Keywords:

Chronic fatigue syndrome, gastro-intestinal tract, biopsy, herpesviruses, parvovirus B19, quantitative PCR

abstract:

http://iv.iiarjournals.org/content/23/2/209.abstract

full-text:

http://iv.iiarjournals.org/content/23/2/209.full.pdf+html

Met dank aan Rob die mij op het uitgebreide studierapport opmerkzaam maakte.