No evidence of persistent mumps virus infection in inflammatory bowel disease.

Abstract

Background and aim-There is controversy regarding whether paramyxovirus infection is causally associated with inflammatory bowel disease (IBD). The latest cohort study claimed that atypical measles and mumps infections in childhood may be risk factors for later IBD. This study was conducted to clarify the validity of a causal link between persistent mumps virus infection and IBD.

Subjects and methods-(1) Amplification of the mumps virus genome was per formed in both intestinal specimens (ulcerative colitis 15, Crohn's disease 15, control 10) and peripheral blood lymphocytes (PBL) (ulcerative colitis : seven, Crohn's disease six, control three) by reverse transcription-polymerase chain reaction (RT-PCR) followed by Southern hybridisation using primers specific to the viral genome encoding phosphoprotein or haemagglutinin-neuraminidase. (2) Titre of serum antimumps IgG was measured in 16: patients with ulcerative colitis, in 16 patients with Crohn's disease, and in 16 normal controls using an 16 enzyme linked immunosorbent assay.

Results-(1) The mumps virus genome was not detected by RT-PCR in intestinal specimens or PBL in any case. (Z) Antimumps IgG titre was positive in 7116 ulcerative colitis, 10116 Crohn's disease, and 11/16 control specimens. The mean (SEM) titre of antimumps IgG was 12.281 (7.831) in ulcerative colitis, 7.675 (1.608) in Crohn's disease, and 8.637 (1.969) in controls, with no significant: difference between the three groups.

Conclusion-We could not find any evidence to support a causal link between persistent mumps virus infection and IBD.

Keywords: inflammatory bowel disease; ulcerative colitis; Crohn disease; mumps virus; measles virus; paramyxovirus

Although the pathogenesis of inflammatory bowel disease (IBD) unknown, it is suggested that IBD occurs in susceptible hosts with some unknown exogenous agents in the environment; one of the most likely candidates is thought to be infections. [1] In this regard a series of studies by Wakefield and colleagues [2-6] claimed, a close link between measles virus and Crohn's disease on the basis of epidemiological and immunohistochemical findings, but this measles hypothesis. is controversial [7] because the measles virus genorne was not detected in. patients with Crohn's disease, [8-11] an the meansles antibody recognised the host protein as well as the measles virus. [12,13]

The latest cohort study [14] from the same group (Montgomery et al) put forward another possibility: a close relationship between mumps virus and IBD-namely, that mumps virus infection before the age of two years was a risk factor for ulcerative colitis, and mumps and measles virus infections in the same year of life were significantly associated. with IBD However, this cohort study did, not include cases who had received measles, mumps, and rubella (MMR) vaccination but it was concerned that the results of the study might provoke reduced uptake of MMR vaccination. [15] Further, it is known that mumps virus establishes persistent infection in mammalian cells. [16] Based on these findings, we wished to clarify the validity of a causal link between persistent mumps virus infection and IBD.

As far as we are aware, only one study [17] tried to detect mumps virus genome in intestinal specimens from patients with IBD but none was detected. However, reverse transcription-polymerase chain reaction (RT-PCR) was performed using only one primer set to the mumps virus genome and the sensitivity of RT-PCR was unknown. [17] Hence it is difficult to reach the conclusion of no causal link between persistent mumps virus infection and IBD from their results alone. Our study was conducted to clarify this issue using RT-PCR followed by Southern hybridisation with high sensitivity, and a serological test for mumps virus.

Materials and methods

AMPLIFICATION OF THE …