Abstract: FR-PO966
IgM-Positive Plasma Cells in Lip Biopsy Specimens from Patients with Tubulointerstitial Nephritis with IgM-Positive Plasma Cells (IgMPC-TIN)
Session Information
- Pathology and Lab Medicine - 1
October 25, 2024 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pathology and Lab Medicine
- 1800 Pathology and Lab Medicine
Authors
- Takahashi, Naoki, Fukui Daigaku, Fukui, Fukui, Japan
- Imafuku, Toshio, Shonan Clinic, Kamakura, Kanagawa, Japan
- Kawaguchi, Takahisa, Kawasaki Shiritsu Kawasaki Byoin, Kawasaki, Kanagawa, Japan
- Iguchi, Akira, Nagaoka Sekijuji Byoin, Nagaoka, Niigata, Japan
- Yamashita, Yawara, Kagoshima Daigaku, Kagoshima, Kagoshima, Japan
- Kasuno, Kenji, Fukui Daigaku, Fukui, Fukui, Japan
- Iwano, Masayuki, Fukui Daigaku, Fukui, Fukui, Japan
- Toyama, Tadashi, Fukui Daigaku, Fukui, Fukui, Japan
Background
In 2017, we introduced the concept of tubulointerstitial nephritis with IgM-positive plasma cells (IgMPC-TIN), in which many IgM-positive plasma cells infiltrate the renal interstitium. Although IgMPC-TIN may be part of a systemic disease, few reports have evaluated IgMPC infiltration in organs other than the kidney and liver in patients with IgMPC-TIN. In this study, we investigate whether many IgMPC infiltrates are also present in lip biopsy specimens of patients diagnosed with IgMPC-TIN on renal biopsy.
Methods
We collected lip biopsy specimens from a total of 18 patients from our hospital and collaborating centers nationwide: 8 patients (IgMPC-TIN group) (7 with Sjögren syndrome) diagnosed with IgMPC-TIN by renal biopsy and 10 patients (non-IgMPC-TIN group) with other diseases (3 with IgG4-related disease, 4 with Sjögren syndrome and 3 with SLE). We used an immunoenzymatic method to do double staining with IgM and CD138 and then counted PC and IgMPC and calculated the percentage of IgMPCs among all PCs in each group. We calculate the cut-off values, sensitivity, and specificity using ROC analysis (SigmaPlot 15.0).
Results
In lip biopsy, the average number of plasma cells (PCs) in the three fields of view was not significantly different (94 vs. 90/high-power field (HPF), P=0.895). The IgMPC-TIN group had a significantly higher average number of infiltrated IgMPCs in the three fields of view (44 vs. 9/HPF, P<0.001), the maximum number of IgMPCs (59 vs. 11/HPF, P<0.001), and a significantly higher percentage of IgMPCs among all PCs (46% vs. 10%, P<0.001). The cut-off values (sensitivity and specificity, respectively) by ROC analysis were the percentage of IgMPCs among all PCs 17.2% (100% and 90%), the average number of IgMPCs 18.8/HPF (87.5% and 90%) and the maximum number of IgMPCs 23.5/HPF (87.5% and 90%). In renal and lip biopsies, there was no significant correlation between the percentage of IgMPCs among all PCs, the average number of IgMPCs in the three fields of view, and the maximum number of IgMPCs.
Conclusion
The IgMPC-TIN group had more IgMPCs in lip biopsies than the non-IgMPC-TIN group. The percentage of IgMPCs among all PCs was most useful in determining IgMPC-associated salivary gland findings. IgMPC-TIN may be a renal manifestation of a systemic disease with IgMPC infiltration.
Funding
- Private Foundation Support