Predictors of response to lymphocyte immunotherapy in infertility and recurrent pregnancy loss: the role of anti-paternal cytotoxic antibodies and hematological inflammatory indices

This study aimed to evaluate whether complete blood count (CBC)-derived inflammatory biomarkers predict immunological response to paternal lymphocyte immunotherapy (LIT) in women with unexplained infertility or recurrent pregnancy loss, using anti-paternal cytotoxic antibody (APCA) seroconversion as the response endpoint. A total of 198 women who underwent LIT were analyzed. Responders showed significantly lower baseline neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), and systemic inflammatory response index (SIRI) than non-responders. ROC analysis indicated that SIRI had the highest predictive performance for treatment response (AUC = 0.801), followed by SII (AUC = 0.769) and NLR (AUC = 0.742). In multivariate logistic regression, higher NLR, PLR, SII, and SIRI were independently associated with a lower likelihood of favorable immunological response. Among the evaluated markers, SIRI emerged as the strongest independent predictor, suggesting that CBC-derived inflammatory indices may provide accessible and cost-effective tools for predicting responsiveness to LIT.