P027 IGG/IGM pre-incubation of whole blood may decrease TNF-a and IL-6 production after SEB stimulation ex-vivo

Introduction Polyclonal intravenous immunoglobulins (IVIGs) can modulate the host immune response. The purpose of the study was to investigate the effect of different immunoglobulin solutions on whole blood cytokine production capacity after staphylococcal superantigen (exotoxin) B (SEB) stimulation ex-vivo . Methods Peripheral heparinized blood was collected from 9 healthy volunteers for complete blood count, and ex-vivo stimulation with SEB. One hundred microliters of blood were added in 900 μl of RPMI 1640 for final volume 1 ml and placed to plastic culture dishes. Samples were added to wells and maintained at 37 °C in a 5% CO 2 atmosphere and then SEB was added (1 μG/ml). After incubation of 8 h the culture plate was centrifuged (1800 rpm, 5 min) and supernatants were collected and stored at −70 °C until cytokines level measurements using the ELISA method. In addition, samples were incubated either with IgG (20 mg IgG/ml) or IgG/IgM (15.2 mg IgG/ml and 2.4 mg/ml IgM) prior (pre-incubation, 2 h) or simultaneously to SEB stimulation. Data are presented as mean ± SEM and comparisons were performed using Kruskal–Wallis test, with post hoc analysis using Dunn’s Multiple Comparison Test. Results Baseline TNF-a levels after SEB stimulation alone and incubation for 8-h was 720.0 ± 143.0 pg/ml. TNF-a levels after simultaneous IgG or IgG/IgM solution administration and SEB stimulation, were 411.0 ± 163.8 and 723.5 ± 199.0 respectively ( p  > 0.05). TNF-a levels after pre-incubation with IgG or IgG/IgM and subsequent SEB stimulation were 133.0 ± 53.9 and 118.2 ± 33.5 respectively and the difference was statistically significant compared to baseline ( p Baseline IL-6 values after SEB stimulation alone were 506.0 ± 91.4. There was a statistically significant decrease in whole blood IL-6 production (91.2 ± 16.2 pg/ml; p  = 0.0275) only in the group of IgG/IgM solution pre-incubation. Baseline IL-10 values after SEB stimulation alone were 28.9 ± 5.3 pg/ml respectively. There was no significant effect on whole blood cytokine production capacity after SEB stimulation by either pre- or simultaneous IgG or IgG/IgM solutions administration. Conclusion Pre-incubation of whole blood with IgG/IgM solution and subsequent administration of SEB may decrease whole blood TNF-a and IL-6 production capacity and thus express an anti-inflammatory effect. The study was partially funded by the Special Account for Research Grants of the National and Kapodistrian University of Athens, Grants 11103 and 3211.