RESUMO
AIM: To detect faults in phagocytosis in peripheral blood cells of pregnant women with systemic lupus erythematosus (SLE) and in cord blood of their newborns. METHODS: Pregnant women fulfilled ≥ 4 American College of Rheumatology criteria for SLE and their newborns were recruited. Pregnant women without SLE and their newborns constituted controls. Phagocytosis and respiratory burst were measured using PHAGOTEST and BURSTTEST kits (Biotechnology GmbH, Germany) on FACSCalibur™ flow cytometer. Expression of CD11b was estimated with antibodies (BD Biosciences, San Jose, CA, USA). Mann-Whitney rank-sum test was used to compare SLE group and controls. RESULTS: Phagocytosis and respiratory burst were estimated in blood of 31 SLE women (29.5 ± 3.3 years) and in cord blood of 26 newborns. Controls were 21 health women (29.8 ± 2.8 years) and their 21 babies. Median reactive oxygen species (ROS) production was reduced in the SLE group versus controls (arbitrary units): women, 2315 versus 3316 (P = 0.034); babies, 1051 versus 1791 (P = 0.041), respectively. Proportion of ROS-producing granulocytes decreased in the SLE group: women, 72.5% versus 94.0% (P = 0.025); babies, 46.8% versus 90.7% (P = 0.008). Proportion of phagocytes which engulfed Escherichia coli and bacteria number per phagocyte also decreased in SLE women. Monocyte activity was suppressed in newborns from the SLE group (RLU): 224 versus 507 (P = 0.022). CD11b expression was reduced in SLE women (RLU): granulocytes, 588 versus 1448.5 (P < 0.001); monocytes, 1017 versus 1619 (P = 0.002). CONCLUSION: Pregnant SLE women have low ingesting capacity of phagocytes. Suppression of phagocytosis in their newborns is mainly due to reduced number of cells producing ROS.
