Impaired Renal Function in Lupus Nephritis May Be Associated With Tertiary Lymphoid Tissue

In lupus nephritis, tubulointerstitial tertiary lymphoid tissue is associated with impaired renal function, according to a new study. However, these lesions were not associated with disease activity indicators.

In several studies, tubulointerstitial lesions have been found in patients with lupus nephritis. These lesions, which consist of inducible ectopic lymphoid tissue, form in the kidney interstitium in response to chronic inflammation. However, the relevance of these lesions in lupus nephritis disease course and the clinical characteristics of patients in whom they form have been unclear. 

To investigate the relevance of these lesions to the pathophysiology of lupus nephritis, researchers at Kyoto University in Japan determined the presence of these lesions in 205 kidney biopsy samples of patients with lupus nephritis and evaluated the clinical characteristics of the patients in whom these lesions were found. They also calculated National Institutes of Health histological activity and kidney damage at biopsy according to chronicity indices.

The researchers found that 43 patients (21%) had tubulointerstitial kidney lesions. They also found that these lesions were associated with a reduction in estimated glomerular filtration rate (eGFR) and greater histological kidney injury scores and incidence of hypertension. In addition, patients with lesions had a history of not being treated with immunosuppressive drugs.

However, the development of these lesions was not associated with disease activity indicators such as proteinuria, complement factors, or Systemic Lupus Erythematosus Disease Activity Index scores.  Moreover, no significant difference in International Society of Nephrology/Renal Pathology Society classification was found between patients with lesions and those without them.

The researchers concluded that the “association between [tubulointerstitial lesion] development and reduced eGFR and higher histological injury [suggests that these lesions could be used] as an additional histological marker for evaluation of [lupus nephritis] disease activity.” Moreover, the absence of association between lesion development and lupus disease activity indices suggests that the development of these lesions is at least in part independent of glomerulonephritis severity.

—Ellen Kurek

Reference:

Sato Y, Kondo M, Fukuma S, Toriu N, Ubara Y, Yanagita M. Tertiary lymphoid tissue development is associated with impaired renal function in lupus nephritis. Paper presented at: American Society of Nephrology Kidney Week 2021; November 4-7, 2021; Virtual. https://www.asn-online.org/education/kidneyweek/2021/program-abstract.aspx?controlId=3606815