This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The purpose of this study is to find examine the role of genetic factors in causing severe asthma. We are focusing initially on interleukin 16 (IL-16), a substance made by the body's white blood cells that may have an important role in asthma. Later, we will also look at other substances and their genes that have been reported in the scientific literature to influence asthma.