Serum Aminoacyl-tRNA Synthetase-Interacting Multifunctional Protein-1 Can Predict Severe Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: A Pilot Monocentric Study

We investigated whetherserumaminoacyl-tRNAsynthetase-interactingmultifunctionalprotein-1(AIMP1) couldpredictseverecases ofantineutrophilcytoplasmicantibody (ANCA)-associatedvasculitis(AAV) based on the Birminghamvasculitisactivity score (BVAS). Sixty-one patients with AAV were selected for inclusion from our prospective AAV cohort. AAV-specific indices and clinical manifestations were assessed, and laboratory tests were performed on the day of blood sampling. Patients withsevereAAV were defined as those with a BVAS higher than the lower limit of the highest tertile of BVAS (BVAS ≥ 12). We measuredserumAIMP1 levels of the storedserumsamples. A total of 20 (32.8%) and 41 (67.2%) patients were classified as havingsevereand nonsevere AAV according to the cut-off of BVAS ≥ 12. Patients withsevereAAV showed higher frequencies of general and renal manifestations, along with ANCA positivity, and exhibited a higher mean neutrophil count, erythrocyte sedimentation rate, and C-reactive protein levels, but lower mean haemoglobin andserumalbumin levels than those with nonsevere AAV. The meanserumAIMP1 level in patients withsevereAAV was significantly higher than that of patients with nonsevere AIMP1 (351.1 vs. 98.4 pg/mL, p = 0.006). Multivariate logistic regression analysis including variables showing significance in univariate analyses revealed that onlyserumAIMP1 exhibited a significant association withsevereAAV (odds ratio 1.004, p = 0.031). When we set the optimal cut-off ofserumAIMP1 forsevereAAV to 50.28 pg/mL, patients withsevereAAV more frequently had AIMP1 levels above the cut-off than those with nonsevere AAV (80.0% vs. 31.7%, relative risk 8.615, p < 0.001). The results from ourstudysuggest thatserumAIMP1 can be used to estimate the cross-sectionalsevereAAV population based on the BVAS.ope