Figure 7.

The Human Omentum Recruits Neutrophils and Collects Bacterial Antigens during Appendicitis

(A,) Representative gating strategy showing CD45⁺ CD19⁻, CD3⁻, NCAM⁻, and CD15⁺ neutrophils in the omentum (Om) of non-inflamed (NI) and appendicitis (App) patients. Histogram showing expression of CD16 and CD14 by omental neutrophils from representative patients with App, and quantification of CD16 and CD14 MFI on CD15⁺ neutrophils from NI (white) and appendicitis (red) patients.

(B) Number of neutrophils found per g of Om or per ml of peritoneal wash (PW) of NI and App patients. Patients were stratified based on surgical outcome into one of two groups, NI (white) or App (red), n = 7 and 10 patients per group. Error bars show SEM.

(C,) Chemokines and cytokines found in 2 h Om explant culture supernatant, PW, and serum comparing NI and App patients. Each column represents one patient.

(D) Amounts of CXCL8 per g per ml of 2 h Om explant culture supernatant.

(E) Representative confocal images of wholemount immunofluorescence staining of omentum biopsies from NI or App patients (n ≥ 6) showing in gray DNA stained with DAPI (upper) or extracellular DNA stained with SYTOX (middle, gray), or CD15 (lower); in magenta CD11b; in green MPO and in red Citrullinated histone H3 (CitH3).

(F) Amounts of double-stranded DNA (dsDNA) released into the supernatant of 2 h omental explant culture per g and per ml and per ml of PW in control and App patients.

(G) LAL activity within the supernatant of 2 h omental explant culture per g and per ml of PW and serum in control and appendicitis patients. n = 10–13 patients per group.

Error bars show SEM. Unpaired Student’s t test or Mann Whitney test was applied after assessing normality using D’Agostino and Pearson and Shapiro-Wilk normality tests, ns = non-significant, ^∗ = p < 0.05, ^∗∗ = p < 0.01, ^∗∗∗p = < 0.001.