Neonatal Lupus Erythematosus (NLE) is a rare acquired autoimmune disease caused by the transplacental transfer of maternal anti-Ro/SSA and anti-La/SSB antibodies. Despite the high prevalence of these antibodies in mothers with Systemic Lupus Erythematosus (SLE) and Sjögren’s Syndrome (SS), the clinical manifestations in neonates are highly heterogeneous, ranging from transient cutaneous lesions to life-threatening congenital heart block (CHB).

This study analyzed a case series of nine mother-infant pairs diagnosed with NLE. We integrated clinical outcomes, maternal serological profiles (including quantitative anti-Ro52, Ro60, and La titers), and pharmacological interventions to explore the determinants of disease severity and organ-specific manifestations.

Maternal serology revealed that 100% of the cohort (9/9) tested positive for high-titer anti-Ro52 antibodies, reinforcing its status as the primary screening biomarker for NLE. Cardiac involvement was observed in three cases, presenting a spectrum of severity. Notably, one fetus diagnosed with second-degree atrioventricular block (AVB) achieved a successful reversal to normal sinus rhythm following aggressive maternal treatment with dexamethasone (4mg/qd). This case confirms the existence of a "reversible inflammatory window" where corticosteroids can suppress immune complex deposition before the onset of extensive fibrosis. Conversely, another case exhibited recurrent third-degree CHB leading to multiple pregnancy losses, highlighting the irreversible nature of collagen scarring in the AV node once the inflammatory phase concludes.Cutaneous manifestations, including annular erythema and periorbital rash, were present in five cases, typically appearing within weeks of birth following ultraviolet (UV) exposure. Hematologic involvement was characterized by a severe case of neonatal thrombocytopenia , necessitating intravenous immunoglobulin (IVIG) intervention. A critical finding was the "sentinel effect": in four cases, the mother's autoimmune status was entirely occult, with the diagnosis established only after the NLE-related fetal bradycardia or neonatal rash occurred, positioning NLE as a vital diagnostic window for maternal health.

Anti-Ro52 (p200 epitope) is the most potent predictor of NLE-related cardiac injury. While cutaneous and hematologic involvements are transient, cardiac NLE requires early detection via serial echocardiography. The prophylactic use of Hydroxychloroquine (HCQ) and timely intervention with fluorinated corticosteroids during the inflammatory phase of AVB are essential to improving neonatal outcomes.