Urinary Immunoglobulin G Is a Novel Biomarker for Atherosclerotic Burden in Mild Acute Ischemic Stroke Patients

Urinary immunoglobulin G (IgG) may be a stronger marker of atherosclerosis than microalbuminuria are because urinary IgG reflects proteinuria level and size-selectivity loss. Microalbuminuria-not urinary IgG-is associated with mild acute ischemic stroke (MAIS).

Using the Jikei University School of Medicine Stroke Registry, we selected and screened patients with symptomatic acute ischemic stroke (onset-to-door time ≤ 24 h). The exclusion criteria were (1) on-admission NIHSS scores ＞10, (2) a modified Rankin Scale (mRS) score ≥ 2 prior to stroke onset, (3) incomplete data (no urinalysis ≤ 3 days after admission or no mRS score at 90 days from stroke onset), and (4) an active malignancy. Patients at 90 days post-discharge were divided into those with favorable mRS scores of 0-1 and those with unfavorable mRS scores of 2-6. Clinical backgrounds were compared for (1) patients with positive and negative urinary IgG results, and (2) patients with favorable and unfavorable outcomes.

Of our study's 210 patients (164=male, median age=68, median eGFR=53.2 ml/min/1.73 m²), 30 (14%) presented with positive urinary IgG, which was associated with cardiovascular risk factors. Higher BNP, higher D-dimer, lower eGFR, and higher CAVI were associated with higher positive urinary IgG. The favorable group, comprising 155 (74%) patients, had higher negative urinary IgG than the unfavorable group (89% vs 76%, P=0.026). No statistical difference emerged regarding microalbuminuria (29% vs 29%, P=1.000).

In MAIS, urinary IgG was associated with both the presence of atherosclerosis and an unfavorable outcome at 90 days after stroke onset.