By the 1990s it was well known that nitric oxide (NO) production in vascular endothelium was intimately linked to inflammation. The presence of excessive levels of cytokines (part of the inflammatory process) stimulates the production of NO in the tissues. While a small amount of NO in vascular endothelium is beneficial and can even be considered anti-inflammatory, the large amounts of NO released in response to cytokines can destroy host tissues [Clancy 1998].

At this time, in the prestigious Karolinska Institute, Stockholm, Lars Gustafsson and Kjell Alving  were working on individual research programmes, examining the properties of exhaled air. In 1991, Gustafsson was the first to report the presence of NO in exhaled air [Gustafsson 1991].  Alving was stimulated by Gustafsson’s findings to investigate the possibility that NO was elevated in patients with inflammatory airways disease. A research device was assembled, and used to measure the exhalations of his colleagues, among which were some allergy sufferers.

This initial experiment produced striking results showing that the allergy sufferers had significantly higher levels of NO in their exhaled air [Alving 1993].

Tests were repeated and the initial results were corroborated, showing conclusively that the level of NO in exhaled air could be used as a sensitive marker for inflammation in the airways.

Gustafsson and Alving decided to join forces to develop a device that could be used routinely to measure exhaled NO in the clinical setting, and in 1997 established Aerocrine as a commercial venture.

Lars Gustafsson	Kjell Alving