Evaluation of Immunological Parameters in Pregnant Women: Low Levels of B and NK Cells.

Objective:  To describe the immunological and hematological reference intervals of low-risk pregnant women.

Methods:  A cross-sectional retrospective database analysis of a basic and translational study analyzing the hematological evaluation blood counts and immunophenotyping of TCD3 + , TCD4 + , TCD8 + , B, and natural killer (NK) cells of the peripheral blood in 79 low-risk pregnant women and of 30 control women from the state of Pernambuco, Brazil, was performed.

Results:  No significant differences were detected between the hematological profiles of the 2 and 3 trimesters. Nevertheless, the median level of B cells decreased significantly in the 2 (174 × 10 µL;  < 0.002) and 3 trimesters (160 × 10 µL;  < 0.001), compared with the control group (296 × 10 µL). Similarly, the median level of NK cells was lower in the 2 (134 × 10 µL;  < 0.0004) and 3 trimesters (100 × 10 µL,  < 0.0004), compared with the control group (183 × 10 µL). In contrast, relative TCD4+ and TCD8+ levels increased in the 2 and 3 trimesters compared with the controls (TCD4 + : 2 trimester = 59%;  < 0.001; 3 trimester = 57%;  < 0.01; control = 50%; and TCD8 + : 2 trimester = 31%;  < 0.001; 3 trimester = 36%;  < 0.01; control = 24%).

Conclusion:  Low-risk pregnant women have ∼ 40% less B and NK cells in the peripheral blood, compared with non-pregnant women. These parameters may improve health assistance for mothers and contribute to define reference values for normal pregnancies.