Figure 2
Assessment of degrees of Cnm-positive S. mutans in the tonsils from patients with IgAN and chronic tonsillitis. (A) Tonsillar sections were obtained from patients with IgAN and chronic tonsillitis. The degree of tonsillar immunoperoxidase staining for Cnm varied among the patients and disease group. (i) Representative tonsil from an IgAN patient (positive Case) showing strong staining, including germinal centers (arrowheads). (ii) Representative tonsil from an IgAN patient (negative Case) showing weak staining, even in the germinal centers. (B) Measurement of ratio of Cnm-positive area to the entire tonsil. Images taken at low magnification were converted to 8-bit red, green, and blue (RGB) images, and a threshold drawing was then generated using the image processing program, Fiji/ImageJ. (C) Receiver operating characteristic (ROC) curves for the ratio of Cnm-positive area to the entire tonsil for predicting cnm positivity in salivary specimens from IgAN patients by PCR. Arrow indicates the cut-off ratio yielding maximum sensitivity and specificity for the prediction of Cnm positivity in the specimen. The optimal cut-off ratio was 0.472 (n = 36, area under the curve = 0.72910; sensitivity = 61.5%; specificity = 87.0%).
