Th1/Th2 Cytokine Balance Shift in Saliva During and After Pregnancy

Objectives: Local inflammatory mediators could be affected from physiological changes in the pregnancy and exacerbate the periodontal inflammation. Th1/Th2 activity balance is strongly shifted towards Th2 activity during physiological pregnancy. The aim of the present study was to evaluate in pregnant and postpartum women the salivary levels of Th1 (IL-2, INF-γ and TNF-α)/Th2 (IL-4, IL-5, IL-6 and IL-10) balance, pro-inflammatory markers (IL-1β and IL-8) and levels of putative periodontal pathogens (P. gingivalis, P. intermedia, T. denticola, T. forsythia, F. nucleatum, C.rectus), and investigate their associations with clinical parameters of periodontal inflammation.
Methods: The following groups were assigned: a) pregnant group and b) postpartum group: the pregnant group re-evaluated 6 months after giving birth. Clinical periodontal parameters were registered. Salivary levels of Th1/Th2 balance, pro-inflammatory markers (IL-1β and IL-8) were measured by a 10-plex immunoassay. Bacterial levels of P. gingivalis, P. intermedia, T. denticola, T. forsythia, F. nucleatum, C. rectus were evaluated by quantitative real-time polymerase chain reaction.
Results: Salivary Th1 levels were similar between the pregnant and the postpartum groups (p=0.143). Regarding Th2 and pro-inflammatory levels, the post-partum group exhibited significantly higher levels than the pregnant group (p=0.014, p=0.011). Th1/Th2 balance was significantly higher in the pregnant group than postpartum group (p=0.004). In both pregnant and postpartum groups, there was a significant shift from a Th1/Th2 balance to a Th2 bias (p<0.0001). F .nucleatum, T. denticola, P. gingivalis and P. intermedia salivary levels were significantly different between pregnant and postpartum groups (p=0.0002, p=0.004, p<0.0001, p<0.0001, respectively). C. rectus and T. forsythia levels were similar in the groups (p=0.515, p=0.363).
Conclusions: There is a significant salivary shift in the Th1/Th2 balance during pregnancy compared to postpartum, which is underlined by an increase of Th2 cytokine levels during postpartum. Such molecular changes may reflect changes in periodontal inflammatory status.