Last Updated: 2003-10-01 16:55:38 -0400 (Reuters Health)

By Anthony J. Brown, MD

NEW YORK (Reuters Health) - Mononucleosis, known by many as the kissing disease, may cause some types of Hodgkin's disease, a cancer of the body's lymph nodes, new research suggests.

Mononucleosis, a debilitating infection that typically lasts a few weeks, is usually caused by infection with Epstein-Barr virus (EBV). Although EBV can be spread through kissing, it can also be passed to others through coughs and sneezes. More than 90% of the world's population is infected with EBV, but only a small minority develops mononucleosis.

"There has been a long-standing association between...mononucleosis and Hodgkin's disease," Dr. Richard Ambinder, author of a related editorial, told Reuters Health. "But the lingering question has been whether EBV infection" actually caused the cancer, he added.

The current findings are "very persuasive in making the case that mononucleosis-associated EBV infection" does, in fact, cause Hodgkin's disease," Ambinder, from the Johns Hopkins School of Medicine in Baltimore, noted. Still, "this doesn't mean that other intervening factors aren't needed for the (cancer) to occur."

The new report and the editorial are published in The New England Journal of Medicine.

The findings stem from a study of more than 60,000 Danish and Swedish patients who were tested for mononucleosis and then followed to determine the rate of Hodgkin's disease.

Mononucleosis was linked with an increased risk of Hodgkin's disease, lead author Dr. Henrik Hjalgrim, from the Statens Serum Institut in Copenhagen, and colleagues note.

However, mononucleosis only raised the risk of EBV-related Hodgkin's disease, not the risk of Hodgkin's disease unrelated to EBV. Overall, it took about 4 years from the mononucleosis episode for Hodgkin's disease to be diagnosed.

The new results go a long way toward clarifying the link between mononucleosis and Hodgkin's disease, Ambinder noted, but many questions still remain.

"EBV infection is very common, but why do only a small percentage of people get infectious mononucleosis?" he pointed out. "And why, among the people who get mononucleosis, do some go on to get Hodgkin's disease?"

A principal question for clinicians is "can the knowledge from the present study be put to use to prevent or facilitate the early diagnosis of Hodgkin's disease," Ambinder said. "I think this is quite an attractive area for further investigation."

SOURCE: New England Journal of Medicine, October 2, 2003.