Myeloid-derived suppressor cells (MDSC) have been studied for their ability to suppress T cell responses in vivo and in vitro. As a result, MDSC can regulate cellular responses to chronic inflammatory conditions such as cancer, leading to the induction of tolerance and, ultimately, tumor escape from immune surveillance.

Inclusion

1. Ages eligible for study: 18 to 60 years
2. Genders eligible for study: male and female
3. Signed and dated written informed consent is obtained prior to study blood draw.
4. Subjects being actively treated for chronic moderate to severe asthma based on National Heart Lung and Blood Institute guidelines (figure 1). Subjects must carry the diagnosis of asthma (made by a physician) for a minimum of six months.
5. Subjects within the first seven days of an acute asthma exacerbation, as determined by the referring physician.
6. Able to give informed consent.

Exclusion Criteria:

1. Use of systemic corticosteroids within the previous two weeks.
2. Pregnant and/or lactating females.
3. Current tobacco use.
4. Severe psychiatric illness.
5. Current illicit substance abuse or dependence and/or abuse of alcohol.
6. Current use of anti-microbial medications.
7. Primary or secondary immunodeficiency.
8. Any clinically significant uncontrolled medical condition that would put the patient's safety at risk.

Ages eligible for study: 18 to 60 years Genders eligible for study: male and female Signed and dated written informed consent is obtained prior to study blood draw.

Subjects being actively treated for chronic moderate to severe asthma based on National Heart Lung and Blood Institute guidelines (figure 1). Subjects must carry the diagnosis of asthma (made by a physician) for a minimum of six months.

Subjects within the first seven days of an acute asthma exacerbation, as determined by the referring physician.Able to give informed consent.