Identification of Serum Biomarkers for CD15+ Hypodense Neutrophils in Severe Asthma

Neutrophils are implicated in the pathophysiology of multiple asthma phenotypes. It was shown
in study IST Q4935s that low-density granulocytes (LDG) are elevated in the blood of patients
with moderate or severe asthma. The greatest frequency and the highest percentages of LDG
were observed in subjects with severe asthma. The LDG, which were first identified and
characterized in systemic lupus erythematosus (SLE) patients, have been reported to display
increased cytotoxicity for endothelial cells, increased tendency to form neutrophil
extracellular traps, and increased production of tumor necrosis factor (TNF). It was also
observed that the LDG expressed increased levels of CD15, which can facilitate attachment of
activated platelets to the LDG. Identification of a putative serum biomarker that correlates
with increased levels of the CD15+ LDG may be useful for the detection of
neutrophil-associated inflammation in severe asthma.

Thirty subjects will be screened to identify 20 subjects with severe persistent asthma. The
following data and/or samples will then be obtained within three weeks of the clinical
assessment: (1) the percentages of LDG will be quantified by flow cytometry; (2) a blood
sample will be collected into a PAXgene Blood tube and stored until shipped to Genentech for
gene profiling analysis; and (3) a serum sample will be collected for measurement of total
immunoglobulin E (IgE) and for future confirmation of potential biomarkers identified in the
gene profiling analyses.

Inclusion Criteria:

- Physician diagnosis of severe persistent asthma;

- Positive skin test or radioallergosorbent test (RAST) for an aeroallergen;

- Male or female age 12-65 years;

- Non-smoker.

Exclusion Criteria:

- Asthma exacerbation requiring treatment with or increase in oral corticosteroids
within 30 days prior to the study;

- Respiratory infection within 30 days prior to the study;

- Starting or requiring a change in allergen immunotherapy within 30 days prior to the
study;

- Having been treated with Xolair within the past year;

- Requiring chronic immunosuppressive therapy;

- Having taken methotrexate, gold salts, cyclosporine, or macrolide antibiotics within 3
months prior to study;

- Having taken an investigational drug within 30 days prior to the study;

- Have a history of drug or alcohol abuse;

- Pregnancy