The immune cell landscape in kidneys of patients with lupus nephritis.

Lupus nephritis is a potentially fatal autoimmune disease for which the current treatment is ineffective and often toxic. To develop mechanistic hypotheses of disease, we analyzed kidney samples from patients with lupus nephritis and from healthy control subjects using single-cell RNA sequencing. Our analysis revealed 21 subsets of leukocytes active in disease, including multiple populations of myeloid cells, T cells, natural killer cells and B cells that demonstrated both pro-inflammatory responses and inflammation-resolving responses. We found evidence of local activation of B cells correlated with an age-associated B-cell signature and evidence of progressive stages of monocyte differentiation within the kidney. A clear interferon response was observed in most cells. Two chemokine receptors, CXCR4 and CX3CR1, were broadly expressed, implying a potentially central role in cell trafficking. Gene expression of immune cells in urine and kidney was highly correlated, which would suggest that urine might serve as a surrogate for kidney biopsies

Treatment of Lupus Nephritis with Abatacept: The Abatacept and Cyclophosphamide Combination Efficacy and Safety Study

OBJECTIVE: To assess the efficacy and safety of a 24-week course of abatacept in the treatment of active lupus nephritis. An additional exploratory objective was to assess the potential of abatacept to induce ‘clinical tolerance’, defined as sustained clinical quiescence of lupus nephritis after discontinuation of immunosuppressive therapy. METHODS: Patients (n=134) with active lupus nephritis were studied in a randomized, double-blind phase II add-on trial in which they received either abatacept or placebo in conjunction with the Euro-Lupus regimen of low-dose cyclophosphamide followed by azathioprine. The primary efficacy outcome was the frequency of complete response (CR) at week 24. Thereafter, patients who met either complete or partial response criteria continued blinded treatment through week 52. During this phase of the study, subjects in the abatacept treatment group who had achieved CR status at week 24 discontinued immunosuppressive therapy other than prednisone (10 mg/d). RESULTS: There were no statistically significant differences between groups with respect to the primary outcome or any of the secondary outcomes, including measures of safety. Thirty-three percent of subjects in the treatment group and 31% of subjects in the control group achieved CR status at week 24. Fifty percent of subjects in the treatment group who met CR criteria and therefore discontinued immunosuppressive therapy at week 24 maintained their CR status through week 52. CONCLUSION: The addition of abatacept to a regimen of cyclophosphamide followed by azathioprine did not improve the outcome of lupus nephritis at either 24 or 52 weeks. No worrisome safety signals were encountered

The immune cell landscape in kidneys of patients with lupus nephritis.

Lupus nephritis is a potentially fatal autoimmune disease for which the current treatment is ineffective and often toxic. To develop mechanistic hypotheses of disease, we analyzed kidney samples from patients with lupus nephritis and from healthy control subjects using single-cell RNA sequencing. Our analysis revealed 21 subsets of leukocytes active in disease, including multiple populations of myeloid cells, T cells, natural killer cells and B cells that demonstrated both pro-inflammatory responses and inflammation-resolving responses. We found evidence of local activation of B cells correlated with an age-associated B-cell signature and evidence of progressive stages of monocyte differentiation within the kidney. A clear interferon response was observed in most cells. Two chemokine receptors, CXCR4 and CX3CR1, were broadly expressed, implying a potentially central role in cell trafficking. Gene expression of immune cells in urine and kidney was highly correlated, which would suggest that urine might serve as a surrogate for kidney biopsies