Summary Immunotherapies based on anti‐programmed death 1/programmed death ligand 1 (PD‐1/PD‐L1) pathway inhibitors may turn out effective in ovarian cancer (OC) treatment. They can be used in combination with standard therapy and are especially promising in recurrent and platinum‐resistant OC. There is growing evidence that the mechanism of the PD‐1/PD‐L1 pathway can be specific for a particular histological cancer type. Interestingly, the data have shown that the PD‐1/PD‐L1 pathway blockade may be effective, especially in the endometrioid type of OC. It is important to identify the cause of anti‐tumor immune response suppression and exclude its other mechanisms in OC patients. It is also necessary to conduct subsequent studies to confirm in which OC cases the treatment is effective and how to select patients and combine drugs to improve patient survival.

The study was undertaken to evaluate macrophage-derived chemokine (CCL22) levels in the peritoneal fluid (PF) and plasma of patients with ovarian cancer (n = 93) in relation to regulatory T cells (Tregs; n = 75). The peritoneal fluid CCL22 concentrations were significantly higher in epithelial ovarian cancer (EOC) patients than in patients with benign tumors-serous cystadenoma (n = 32). There was no difference in plasma levels of CCL22 in EOC patients compared with the non-cancer and healthy volunteers (n = 10). There were no significant differences in the plasma and PF CCL22 levels based on tumor grade. However, women with stage IV FIGO (International Federation of Gynecologists and Obstetricians) had significantly higher plasma CCL22 levels than patients with stages I and III. Women with stage I FIGO had significantly higher PF CCL22 levels than patients with stages II and III. Women with endometrioid cystadenocarcinoma had higher PF CCL22 levels than women with undifferentiated carcinoma. The percentage of tumor-infiltrating Tregs (11.06 %) was significantly higher compared to PF (3.05 %) and peripheral blood (PB) (2.01 %). Moreover, the percentage of Tregs was higher in the PF than in the PB of EOC patients. There were no significant differences in the PB, PF, and tumor-infiltrating Tregs percentage based on tumor stage, grade, or histology. Elevated levels of CCL22 found in the ascites could create a chemokine gradient aiding in Treg cells migration. Increased Tregs percentage in the local microenvironment of ovarian cancer might be an important mechanism of immunosuppression.

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Introduction and objective. Data on the possible role of peritoneal fluid free radical-mediated oxidative damage in the pathogenesis of endometriosis still remains inconsistent. The aim of the study was to determine iron metabolism markers and their influence on oxidative stress parameters in the peritoneal fluid of women with endometriosis. Materials and method. 110 women with endometriosis and 119 patients with benign ovarian cysts were included in the study. All visible peritoneal fluid was aspirated during laparoscopy from the anterior and posterior cul-de-sacs. under direct vision to avoid blood contamination. Haemoglobin, iron, total oxidative status, and total antioxidant status were measured using standard colourimetric kits. Results. Haemoglobin, iron levels, as well as total oxidative status values were significantly higher, whereas total antioxidant status values were significantly lower in the peritoneal fluid of patients with endometriosis, in comparison to the reference groups. No differences were observed in peritoneal fluid concentrations of all parameters measured in relation to the phase of the menstrual cycle. Conclusions. Peritoneal fluid of women with endometriosis is characterized by disrupted iron metabolism. This is most likely related to an increased number of erythrocytes in the peritoneal cavity of endometriotic women, which leads to a higher concentration of haemoglobin in this environment. Impaired iron homeostasis may have a significant influence on the pathophysiology of peritoneal endometriosis by the direct impact of haemoglobin derivatives and/or formation of the pro-inflammatory and pro-oxidative environment. Peritoneal cavity oxidative stress occurs predominantly in women in advanced stages of the disease.

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