Could immune cells be associated with nephropathy in Fabry disease patients?

In Fabry Disease (FD), although the primary factor initiating kidney damage is glycosphingolipid accumulation, secondary conditions such as increased inflammation and fibrosis may cause this damage to progress. These processes may be induced by immune cells. Therefore, we aimed to investigate the peripheral lymphocyte subgroup analysis of the patients with FD and compare these results with healthy individuals. In addition, we performed T, B, NK, and plasma cell analyses in kidney biopsy materials and compared these kidney biopsy results with the biopsy results of patients whose kidney functions were impaired after 4 years of regular ERT.

18 FD and 16 healthy individuals were included in the study. T-B lymphocyte and NK-cell populations were determined. We performed kidney biopsies (KBx) on 13 patients with FD prior to ERT. Of these, 4 patients had rebiopsy after 4 years of regular ERT. Immunohistochemical staining was performed to define immune cell infiltration.

There was no statistically significant difference in terms of total, helper and cytotoxic T-lymphocyte and CD3^-CD16⁺CD56⁺ natural killer (NK)-cell count (p = 0.20; p = 0.12; p = 0.76; p = 0.75, respectively).According to KBx findings prior to ERT, all patients had interstitial fibrosis (IF), podocyte vacuoles (PV), and podocyte inclusion (PI), CD3, CD4, CD8, CD16, and CD56 positivity at different levels. None of the patients had CD19, CD20, and CD138 positivity at the first biopsies. When we compared the first and the second KBx results of the two progressors, we also demonstrated that CD3⁺4⁺T-cells infiltration remained the same, whereas CD8⁺T cells, CD16⁺ and 56⁺NK-cells infiltration were significantly decreased. In contrast, CD20⁺B cells and CD138⁺plasma cell infiltration were significantly increased despite 4 years of ERT (15 fold and sixfold, respectively). The CD20⁺B and CD138⁺ plasma cells and IF were positively correlated with proteinuria.

The progression of FD nephropathy and proteinuria is increased despite a long-term ERT. Immune cells, primarily B and plasma cells, might cause these unwanted consequences.