First of its kind renal biopsy research has revealed that Indigenous Australians with lupus nephritis have a lower degree of renal inflammation compared to non-Indigenous patients, despite a larger burden of renal immune deposits.
Lead researcher and rheumatologist Professor Johannes ‘Hans’ Nossent from the University of Western Australia tells us about his findings.
What’s the issue this research is trying to solve?
Are the microscopic findings in the kidneys of Indigenous patients with lupus nephritis and the following disease course similar to well described findings in non-Indigenous patients ?
Were there any aspects of your results that surprised you?
The surprise finding was that while more immune complex deposition was present in the kidneys of indigenous patients, they demonstrated lower levels of renal inflammation than non-Indigenous patients.
This suggest that many of the immune deposits in the kidneys of Indigenous Australians are non-pathogenic /not related to kidney inflammation.
They may be a reflection of the much higher levels of IgG seen in Indigenous patients , which are most likely the result of a combination of genetic influences and natural autoantibodies associated with previous infections.
These high IgG levels also confounds many of the tests for autoimmunity (e.g. RF and ANA test).
Despite this lower burden of renal inflammation, the overall outcome was worse for Indigenous Australians, which was not a large surprise given the fact that Indigenous Australians do worse with a number of diseases where it is hard to tease out the effect of medical and social confounders.
Do your findings fill a gap in our knowledge on lupus nephritis?
Yes, this is the first study to describe detailed renal biopsy findings in Indigenous Australians.
What are the clinical implications of your research?
The clinical implication is that in Indigenous Australians there is a significant discrepancy between autoimmune findings in serum and kidneys compared to non- Indigenous patients; the exact implications of this need to be worked out in more detail.
What do we need to study next?
1) A larger cohort study in Indigenous Australians with lupus nephritis and a control group which also provides more detailed follow-up information (disease flares, drug treatment, adherence)
2) A basic science project investigating the background of the high levels of natural autoantibodies/autoimmunity (e.g. B cell genes and B cell activators) inIndigenous Australians and determine if the high IgG levels serve a protective role or are a precursor of autoimmunity and autoimmune disease.
You can read the full research paper published in the International Journal of Rheumatic Diseases here.