Recent research suggests that the oral cavity may provide an early opportunity to monitor the innate immune system; an oral rinse assay was found to be a reliable predictor of bone marrow engraftment and neutrophil recovery in patients undergoing bone marrow transplantation . Multiorgan failure may be mediated by neutrophil extravasation and aggregation  in highly inflammatory states, such as cardiopulmonary bypass (CPB). The objective of this novel pilot study was to determine whether the kinetics of oral neutrophil recovery post-CPB surgery reflect systemic immune activation.
Samples  from four-quadrant mucosal swabs and oral cavity rinses were obtained from 41 patients undergoing on-CPB elective cardiac surgery preoperatively (t-1) and postoperatively upon arrival to the CVICU (t0), at 12 to 18 hours (t1), and on day 3 (t2). Oral neutrophil counts (/ml) were determined by hemacytometry and validated by an electronic cell counter. Concurrent blood samples were collected for measurement of IFNα, interleukins (IL-1β, IL-6, IL-8 and IL-10), chemokine C-C motif ligand 4 (CCL-4) and Th1 and Th2 cytokines using a 10-plex human cytokine mediator panel. Continuous variables were summarized with means (standard deviation). Preoperative and postoperative oral neutrophil counts were compared using paired t tests.
Patients were 65 (10.6) years old; 78% male; 51% had significant co-morbidities (25% diabetes); 54% took a statin; APACHE II score was 22 (4.4); and multiorgan dysfunction score (MODS) was highest on hospital day 1 (6.2; 2.2). Mean delta oral neutrophil count by oral swab (between t-1 and t0) was 1.7 × 106 (2.0 × 106). A significant difference was seen in the absolute neutrophil counts (oral swab) between t-1 (1.7 × 106 (1.3 × 106)) and t0 (3.4 × 106 (2.7 × 106); P < 0.001), but not between t-1 and t1 (2.0 × 106 (1.7 × 106); P = 0.14) or t2 (6.6 × 105 (1.1 × 106); P = 0.14). Similar results were obtained by oral cavity rinse.
An oral swab assay has the potential to provide rapid, risk-free, and early data on neutrophil activation and chemotactic defects in response to CPB, obviating the need for invasive sampling. This method could provide a new perspective on the systemic inflammatory response in surgery, traumatic injury, burns, and sepsis.