A Study of the Effects of RoActemra/Actemra (Tocilizumab) on Neutrophils in Patients With Active Rheumatoid Arthritis Who Have an Inadequate Response to Biologic and/or Non-biologic DMARDs.

Aging neutrophils translocate phosphatidylserine from the inner leaflet of the plasma membrane to the outer leaflet during the early stages of apoptosis. This translocation can be measured due to the affinity of fluorescein isothiocyanate (FITC)-labeled annexin V to bind exposed phosphatidylserine. Cells that stain positive to Annexin V binding are apoptotic. At 4 hours (hrs) and 20 hrs stimulated and control samples were analyzed for levels of apoptosis.

Aging neutrophils translocate phosphatidylserine from the inner leaflet of the plasma membrane to the outer leaflet during the early stages of apoptosis. This translocation can be measured due to the affinity of FITC-labeled annexin V to bind exposed phosphatidylserine. Cells that stain positive to Annexin V binding are apoptotic. At 4 hrs and 20 hrs stimulated and control samples were analyzed for levels of apoptosis. GM-CSF is an agent that delays apoptosis. Percentage of cells that stained positive for Annexin V binding in the presence or absence of GM-CSF (GM-CSF delayed or constitutive) were determined by flow cytometry.

Neutrophils were incubated with labeled antibodies against CD11b. Flow cytometry was used to determine the mean fluorescence intensity. Greater fluorescence correlates with greater adhesion, migration, and ingestion of complement-opsonized particles.

Neutrophils were incubated with labeled antibodies against CD18. Flow cytometry was used to determine the mean fluorescence intensity. Greater fluorescence correlates with greater adhesion, migration, and ingestion of complement-opsonized particles.

Neutrophils were incubated with labeled antibody against CD62L (L selectin). Flow cytometry was used to determine the mean fluorescence intensity. Greater fluorescence correlates with greater adhesion of neutrophils to vessel walls.

Neutrophils were incubated with labeled antibody against CD63b. Flow cytometry was used to determine the mean fluorescence intensity. Greater fluorescence correlates with greater azurophilic degranulation, an indicator of greater microbe killing.

Neutrophils were incubated with labeled antibody against IL-6R. Flow cytometry was used to determine the mean fluorescence intensity. Greater fluorescence correlates with greater density of membrane bound IL-6 receptor.

Neutrophils were incubated with labeled antibody against mTNF. Flow cytometry was used to determine the mean fluorescence intensity. Greater fluorescence correlates to a greater density of membrane bound TNF.

Using luminol as a substrate for reactive oxidants, a chemical reaction is produced resulting in photon emission (chemiluminescence). fMLP stimulation is mediated through the fMLP receptor on the cell surface. The fMLP response is only observed in primed neutrophils and response is a measure of in vivo priming. Measurements of reactive oxygen species are calculated as total chemiluminescence or the AUC.

Using luminol as a substrate for reactive oxidants, a chemical reaction is produced resulting in photon emission (chemiluminescence). PMA is a receptor-independent stimulator of the respiratory burst and the PMA response measures the total capacity of neutrophils to generate reactive oxidants. Measurements of reactive oxygen species are calculated as total chemiluminescence or the AUC.

S. aureus were heat killed then labeled with PI and opsonized with AB serum (SAPI). S. aureus was then incubated with the neutrophils for 30 minutes at 37 degrees Celsius. The neutrophils were washed, then the percentage of cells positive for the labeled S. aureus (that is, phagocytosed) was calculated via flow cytometry. A higher percentage represented more active phagocytosis.

Phagocytosis can be measured by incubating neutrophils with PI-labeled heat killed S. aureus following incubation for 30 minutes. Neutrophils are co-incubated with DHR, which becomes oxidized by the products of the respiratory burst generated during phagocytosis. Fluorescence can then be measured by flow cytometry.

The DAS28 is a combined index for measuring disease activity in rheumatoid arthritis. The index includes swollen and tender joint counts, acute phase response (erythrocyte sedimentation rate [ESR] or C-reactive protein [CRP]), and general health status. The DAS28, which uses a 28 joint count, is derived from the original DAS, which includes a 44 swollen joint count. The DAS28 scale ranges from 0 to 10, where higher scores represent higher disease activity.

Benefit:Risk was defined at the participant level. It was considered acceptable if the DAS28 improvement represented at least a moderate European League Against Rheumatism (EULAR) response. The risks were based on the known adverse event (AE) profile of tocilizumab rather than on the actual AEs experienced by each participant