Human T Lymphotropic Virus Type 1 Infection and Gastric Cancer Development in Japan

Abstract

HTLV-1 infection likely reduces the risk of H. pylori infection and proliferation and, thereby, the risk of gastric cancer.

Viral Commensalism in Humans?

“…Could there be an interaction between HTLV-1 and H. pylori? This study and several previous studies provide evidence that HTLV-1–positive hosts carry H. pylori less often than do HTLV-1-negative hosts [1, 4, 5]. Thus, one potential explanation is that the immunological context created by HTLV-1 is inhibitory to H. pylori .…”

“…In this issue of the Journal, Matsumoto et al [1] asked whether human T lymphotropic virus type 1 (HTLV-1) antibody status is associated with the risk of developing gastric cancer. In a cohort of >5000 patients aged >40 years who were enrolled during 1989–1992 in an HTLV-1–endemic area, they identified 1812 subjects who underwent endoscopy of the upper gastrointestinal tract before 2003.…”

“…This could occur by reduction of the extent or distribution of gastric inflammatory responses to H. pylori or, possibly, of the progression of inflammation into atrophy and intestinal metaplasia. Since HTLV-1 is acquired early in life [1, 2], its acquisition could affect the milieu in which a subsequent H. pylori colonization takes root; a precedent for early life phenomena to affect H. pylori –associated risk of gastric cancer decades later recently has been reported [6]. …”

“…Could there be benefits as well? The article by Matsumoto et al [1] ultimately raises this question. Since the time of Koch, the advances of medical science have made it easier to recognize new pathogens to understand their pathogenic effects.…”

Breastfeeding and early infection in the aetiology of childhood leukaemia in Down syndrome

“…If infections during the first year of life are a genuine factor, our findings may imply that in Mexico City these peaks have different etiologies with infection being more important for the 6 -9 years age group. The relevant agents may be viewed as having an indirect leukemogenic effect, as in situations reported in relation to cancer in adults (Matsumoto et al, 2008).…”