Peripheral blood dendritic cells subpopulations in women with ovarian carcinoma during chemotherapy. Objectives: Ovarian carcinoma (OVC) is often diagnosed at an advanced stage and requires effective chemotherapy as a first-line treatment. However, chemotherapy may be associated with significant side-effects, like nausea, vomiting, hair loss, cognitive dysfunction, fatigue and changes in sexual functioning. Leucopenia is one of the most common and dangerous side effects of chemotherapy. Little is known about possible effects of chemotherapy on dendritic cells (DCs) counts and function, although it is well documented that primary and secondary cell-mediated immune response are suppressed during this treatment. Design: In this study we evaluated the myeloid and lymphoid DCs in the peripheral blood (PB) of 37 women with OVC before and after first-line based on platin and taxane chemotherapy, and in 24 healthy blood donors. Patients received 6 courses of treatment, administered at 21-day intervals. Material and Methods: The myeloid (M) and lymphoid (L) DCs were estimated by flow cytometry before and after 9th and 15th week of treatment. Results: The percentage of both MDCs and LDCs was significantly lower (0.09% and 0.04%) in PB of patients with ovarian cancer comparing to healthy women (0.25% and 0.33%). The percentage of both, myeloid and lymphoid DCs after 9th and 15th week (0.08% vs 0.08% and 0.06% vs 0.08%) of chemotherapy did not differ from that found before treatment (0.09% and 0.04%). The Myeloid to Lymphoid DCs ratio was significantly lower in patients receiving chemotherapy.