Human infectious diseases and risk of preeclampsia: an updated review of the literature

Preeclampsia (PE) is one of the major causes of maternal and perinatal morbidity and mortality, especially in low- and middle-income countries. In recent years, a growing body of literatures suggests that infections by bacteria, viruses, and parasites and their related inflammations play an important role in the pathogenesis of PE. We searched PubMed, Google scholar, and Cochrane databases using the following search words: "infection and preeclampsia," "bacterial infection and preeclampsia," "viral infection and preeclampsia" and "parasitic infection and preeclampsia." The literature review revealed that many bacteria including Helicobacter pylori, Chlamydia pneumonia, and those are involved in periodontal disease or urinary tract infections (UTIs) and some viral agents such as Cytomegalovirus, herpes simplex virus type-2, human immunodeficiency virus, and some parasites especially Plasmodium spp. and Toxoplasma gondii can be effective in development of PE. Inflammation responses against infections has major role in the inducement of PE. The shift of immunological cytokine profile of Th2 toward Th1 and high levels of pro-inflammatory cytokines (TNF-E, IL-12, IFN-gamma, etc.), increase of oxidative stress, increase of anti-angiogenic proteins, increase of vascular endothelial growth factor receptor 1 (sVEGFR1), and complement C5a are the main potential mechanisms related to infections and enhanced development of PE. Thus, early diagnosis and treatment of bacterial, viral, and parasitic infections could be an effective strategy to reduce the incidence of PE.