OLDER people don’t smell so bad – at least not those in the US. A study has found no evidence of chemicals previously blamed for an unpleasant “ageing odour” in the skin secretions of Americans in their forties and above.

In 2001, researchers at cosmetic company Shiseido ’s Product Development Center in Yokohama asked a group of Japanese men and women to sleep in T-shirts for three consecutive nights. The researchers then studied the volatile chemicals picked up by the material. Volunteers over 40 produced an unsaturated aldehyde called 2-nonenal, which the team described as having an unpleasant “greasy” smell.

“I thought, I’m way older than some of these guys, and I don’t think I smell that bad! My wife would have told me a long time ago,” jokes George Preti of the Monell Chemical Senses Center in Philadelphia, Pennsylvania, who led the new study with his colleague Michelle Gallagher.

To investigate further, Preti and Gallagher asked 13 men and

12 women to walk up and down stairs for 5 minutes, and then placed glass funnels over their backs and forearms for the next 30 minutes. The funnels contained a fibre that absorbed a sample of the chemicals given off. To complete the picture, the researchers also swabbed the volunteers’ forearms and backs using an organic solvent, and analysed the compounds that this picked up.

There were some differences between older and younger volunteers. For instance, over-40s gave off more dimethylsulphone, which comes from the metabolism of sulphur-containing amino acids. However, this compound does not have a strong smell. What’s more, there was none of the foul-smelling chemical found by the Shiseido team (British Journal of Dermatology, DOI: 10.1111/j.1365-2133.2008.08748.x).

Why should older Americans smell better than ageing Japanese? “I attribute it to diet,” says Preti, who notes that the typical Japanese diet contains

much more seafood. This would cause a build-up of unsaturated fatty acids over time, which can be oxidised to 2-nonenal and related compounds. The Japanese team also found that older people’s skin produced more lipid peroxides, which would accelerate this oxidation.

Even though Preti and Gallagher got their volunteers to use unscented soaps and shampoo for at least a week prior to the experiment, many of the

chemicals they found came from cosmetic products – in particular residues from shampoos given off from the backs of the women. “Girls use these shampoos more than guys,” says Gallagher. “It’s not a true gender biomarker.”

Preti and Gallagher are also studying odours given off by a form of skin cancer called basal cell carcinoma, to see if the way these differ from normal skin odours can be used to aid diagnosis. Peter Aldhous ●

THE first “universal” allergy therapy is a step closer following successful trials in people allergic to house dust mites and cat dander.

The series of shots has the potential to treat a host of different allergies because it doesn’t rely on giving people tiny doses of the specific substance that they are allergic to, unlike most existing therapies. Instead, it works by distracting the overactive immune system, which is thought to be the

cause of most allergic reactions. Patients receive a molecular “decoy” which makes their body behave as if it is under attack by a bacterium. Distracted, it stops reacting to otherwise harmless allergens.

“It’s the first allergen-independentimmunotherapy,” says Claudine Blaser of Cytos Biotechnology, the company developing the treatment in Zurich, Switzerland.

Two years ago, much smaller trials suggested that the decoy – called CYT003-QbG10 – might work (New

Scientist, 28 September 2006, p 14). Now Cytos has carried out two larger trials with promising results.

On 10 July, the company announced that 80 volunteers with either house dust mite or cat dander

allergy who received a six-shot course of CYT003-QbG10 had experienced a 61 per cent reduction in symptoms , twice that seen in volunteers who received a placebo.

In a parallel trial, in which 93 patients with dust-mite allergy received CYT003-QbG10 plus the dust-mite allergen, the reduction in symptoms was just 54 per cent, indicating that the therapy works best alone. “From the data, the ‘monotherapy’ clearly gives the best results,” says Blaser. Only 20 of the

volunteers who received the monotherapy reported adverse side effects, such as headaches, one-tenth the number reported by those receiving the combination therapy.

“Now we want to consider it for a broad range of allergies,” says Blaser. Cytos will start a trial of the monotherapy in 300 people with dust-mite allergy later this year and another trial in people with hay fever next year.

“Cytos may have found the holy grail of allergy,” says Neil Kao , an allergy physician based in Greenville, South Carolina. Still, he says, further and larger studies are needed to determine the long-term effectiveness and safety of the series of shots. Andy Coghlan ●

Countdown to a universal allergy treatment

Nothing fishy about these elder statesmen

“A molecular ‘decoy’ makes the body behave as if it is under attack by a bacterium and stop reacting to harmless allergens”

www.newscientist.com 19 July 2008 | NewScientist | 11

–Smells like teen spirit–

JOH

NER

/PLA

INPI

CTUR

E