Among the 28 MGUS/SM patients with a positive “PV/CVB” dot blotting assay, 21 (75.0%) had serum antibodies to the “PV1” peptide; 16 (57.1%) had antibodies to the “PV3” peptide; and 19 (67.9%) had antibodies to the “CVB1/3” peptide. Here, PLVAP is linked to systemic mastocytosis.