Complement C3a, But Not C5a, Levels in Amniotic Fluid Are Associated with Intra-amniotic Infection and/or Inflammation and Preterm Delivery in Women with Cervical Insufficiency or an Asymptomatic Short Cervix (≤ 25 mm)

BACKGROUND: We aimed to estimate whether elevated levels of complement C3a and C5a in amniotic fluid (AF) are independently associated with increased risks of intra-amniotic infection and/or inflammation (IAI) and spontaneous preterm delivery (SPTD) in women with cervical insufficiency or a short cervix (≤ 25 mm). METHODS: We conducted a retrospective cohort study of 96 consecutive women with cervical insufficiency (n = 62) or a short cervix (n = 34) at 17 to 27 weeks, and who underwent an amniocentesis. AF was cultured and analyzed for C3a and C5a by enzyme-linked immunosorbent assay kits. The primary outcome measures were IAI (defined as a positive AF culture and/or an elevated AF interleukin-6 level [≥ 7.6 ng/mL]) and SPTD at < 32 weeks. RESULTS: In multivariable analysis, AF level of C3a was the only variable significantly associated with IAI, whereas C5a level in AF and serum C-reactive protein level were not associated with IAI. Using SPTD at < 32 weeks as the outcome variable in logistic regression, elevated AF levels of C3a were associated with increased risk of SPTD at < 32 weeks after adjusting for other baseline confounders, whereas elevated AF levels of C5a were not. CONCLUSION: In women with cervical insufficiency or a short cervix, elevated AF level of C3a, but not C5a, is independently associated with increased risks of IAI and SPTD at < 32 weeks. These findings suggest that subclinical IAI or SPTD in the context of cervical insufficiency is related to activation of complement system in AF.

Deficiency of C3a/C5a receptors protect kidney from injury in IgA nephropathy / 中国免疫学杂志

Objective:To investigate the role of C3a,C5a and their receptors in the pathogenesis of IgA nephropathy (IgAN). Methods:A total of twenty-eight 6-8 weeks old female BALB/c mice were investigated.And they were negative control group , WT group,C3aR-/-group,C5aR-/-group(the latter three groups were named as experimental groups ),seven mice in each group.All the mice were infected through respiratory tract with infectious SV (experimental groups) or PBS(negative control group),combined with tail vein challenge to make IgAN animal model.Testing 24 h total urinary protein , serum urea nitrogen ( BUN ) and creatinine ( Cr ) , using direct immunofluorescence to test the renal deposition of IgA and C 3,observing renal pathologic lesion under PAS staining with light microscopy.RT-qPCR was used to test the relative mRNA expression of TNF-α,TGF-β,IL-1β,IL-6,MCP-1.Results: After 15 weeks,the level of UTP in experimental group was significantly higher than negative control group ,and the same results as WT group than C3aR-/-group and C5aR-/-group.There was no significant difference among groups for BUN and Cr.Combined with negative control group , experimental groups had significant renal pathological lesions , and the changes of WT group was more severe than C3aR-/-group and C5aR-/-group.The results of relative mRNA expression of TNF-α,TGF-β,IL-1β,IL-6,MCP-1 was the same as the level of 24 h UTP,at the same time,the relative mRNA expression of IL-1β,IL-6,MCP-1 in C3aR-/-group was significantly less than C5aR-/-group.Conclusion:The deficiency of C3a/C5a receptors can protect kidney from injury in IgAN ,and C3a receptor has more significant role in protect kidney from injury in IgAN.