elevation of complement c3/c4, immunoglobulins, and hs-crp in women with recurrent implantation failure: insights from a cross-sectional analysis

Objectives: plasma levels of complement proteins c3, c4, immunoglobulins (iggs), and c-reactive protein (crp) are crucial in understanding recurrent implantation failure (rif). this study aims to quantify these biomarkers and explore their clinical significance. methods: we conducted a cross-sectional study at arash hospital from december 2021 to december 2023, involving 50 women with a history of rif after in vitro fertilization (ivf) and a control group of 50 healthy, fertile women. serum levels of c3, c4, igg, igm, iga, crp, and hs-crp were measured using immunoturbidimetric assays and elisa. results: plasma levels of complement components c3 and c4, igg, iga, crp, and hs-crp were significantly elevated in women with recurrent implantation failure (rif) compared to fertile controls. a positive correlation existed between c3 and c4 in the rif group, but no significant correlations were found for igg, iga, or igm. in contrast, fertile controls showed significant associations between igg, c3, c4, and crp, with igg levels also correlating with iga. roc curve analysis indicated strong discriminatory power for igg, iga, c3, and c4 (all p < 0.001). crp auc was 0.962, and hs-crp auc was 0.994, distinguishing rif from fertile women, with crp showing 94% sensitivity and 92% specificity at 5.3 mg/dl, and hs-crp showing 98% sensitivity and specificity at 2.92 mg/l. conclusion: the findings suggested that elevated plasma levels of c3, c4, igg, and iga in the rif group may be associated with the underlying mechanisms of rif.