Table 1 Subjects’ selection criteria

Sex

Male

Age

50–53 years old

Subjects relationship

All individuals were first cousins

Diet

A Mediterranean diet was followed for 1 month before the day sampling. Pollen- and allergen- associated food, such as apple, hazelnut, celery, strawberries, shellfish and read meat were excluded from diet. Furthermore, milk intake was not recommended. Foods and beverages allowed were: bread, potatoes, vegetables, fresh fruit, meat and meat products, fish and fish products, eggs, edible fat, coffee, tea and soft drinks

Lifestyle

All individuals lived in the same neighborhood. No sport or daily exercises were practiced during the study period. No travel or excursion were carried out for at least 1 month before the day of sampling

Occupation

All subjects had a sedentary office work

Sexual activity

No sexual activity for 2 weeks before the day of sampling

Clothing

All individuals used only cotton clothes for all the study period

Pharmacological therapy

No antibiotic therapy was administered for at least 1 month before the day of sampling and they were not subjected to any kind of pharmacological therapy

Probiotic therapy

No probiotic therapy was administered for at least 1 month before the day of sampling

Personal care

All subjects used Cetaphil, a free-preservatives soap, once a day for 1 month before the day of sampling. Cetaphil is an oil-in-water petrolatum-based cream used to treat dry skin and often recommended for the management of AD. Moreover, no skin perfume or cream was used during the study

Others

No allergy to food, dust, pollen, grasses and drugs was present

The subjects enrolled in the study shared no genetic diseases

All subjects had not pets and/or contacts with any kind of animals

All individuals were nonsmokers and not subjected to passive smoking

The day of sampling took place the same day for all subjects enrolled in the study. The study was conducted during the winter season, in order to avoid excessive sweating