NK cells in pregnant patients with SLE: a preliminary study

The innate immune system plays an important role in reproduction, with marked involvement of NK cells. These cells behavior during pregnancy may clarify crucial points in the pathogenesis of complications that may occur in pregnant women with SLE. OBJECTIVE: To measure the amount of circulating NK cells and their viability in pregnant SLE patients. MATERIALS AND METHODS: Blood samples from four groups of ten patients each were evaluated: 1. GLES: Pregnant SLE patients; 2. PLES: Non-pregnant SLE patients; 3. Gcontrols: Pregnant controls; 4. Controls: Healthy non-pregnant women. In all patients the amount and viability of NK cells was measured by flow cytometry, as well as the total apoptosis by annexin V and propidium iodite staining. RESULTS: Due to the great variability, median of each group was used for evaluation: CD56+ count [GLES (0.10), PLES (0.12), Gcontrols (0.15), Controls (0.08)]; total apoptosis (addition of initial and late apoptosis to total number of dead cells) [GLES (0.06), PLES (0.04), Gcontrols (0.11), Controls (0.11)]. The results for live cells count had low variability, so the averages and standard deviations were used for comparisons: [GLES (0.91±0.06), PLES (0.95±0.03), Gcontrols (0.86±0.11), Controls (0.88+0.08)]. CONCLUSION: Although not statistically significant, the total apoptosis in the SLE groups was lower than in the control groups, and the live cell count was higher. This suggests that in SLE patients, pregnant or not, the NK cells have a prolonged life cycle (or have a lower/different turnover), and that there may be a higher immune stimulus making the NK cells take longer to activate the apoptosis process.

pregnancy; systemic lupus erythematosus; NK cells

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