Disease profiles in the Indigenous Australian population are suggestive of a common complement control haplotype

Aboriginal and Torres Strait Islander People (respectfully referred to as Indigenous Australians herein) are disparately burdened by many infectious and chronic diseases relative to Australians with European genetic ancestry. Some of these diseases are described in other populations to be influenced by the inherited profile of complement genes. These include complement factor B, H, I and complement factor H-related (CFHR) genes that can contribute to a polygenic complotype. Here the focus is on the combined deletion of CFHR1 and 3 to form a common haplotype (CFHR3-1Δ). The prevalence of CFHR3-1Δ is high in people with Nigerian and African American genetic ancestry and correlates to a higher frequency and severity of systemic lupus erythematosus (SLE) but a lower prevalence of age-related macular degeneration (AMD) and IgA-nephropathy (IgAN). This pattern of disease is similarly observed among Indigenous Australian communities. Additionally, the CFHR3-1Δ complotype is also associated with increased susceptibility to infection with pathogens, such as Neisseria meningitidis and Streptococcus pyogenes, which also have high incidences in Indigenous Australian communities. The prevalence of these diseases, while likely influenced by social, political, environmental and biological factors, including variants in other components of the complement system, may also be suggestive of the CFHR3-1Δ haplotype in Indigenous Australians. These data highlight a need to define the Indigenous Australian complotypes, which may lead to the discovery of new risk factors for common diseases and progress towards precision medicines for treating complement-associated diseases in Indigenous and non-Indigenous populations. Herein, the disease profiles suggestive of a common complement CFHR3-1Δ control haplotype are examined.

Genetic Variant CFH rs6677604 Might Play a Protective Role in lupus Nephritis

BACKGROUND

This study aimed to explore the associations between the complement factor H (CFH) rs6677604 and clinico-pathological characteristics of lupus nephritis.

MATERIALS AND METHODS

A total of 188 patients with lupus nephritis with complete clinico-pathological data were enrolled and genotyping of CFH rs6677604 was conducted by TaqMan SNP genotyping assays. Patients were divided into two groups by rs6677604-AA/AG or -GG, and the clinico-pathological features between the two groups were further compared.

RESULTS

We found that patients with rs6677604-AA/AG presented with lower prevalence of anti-dsDNA antibody (12/24 [50.0%] vs 121/164 [73.8%], P = 0.028), higher level of plasma C3a (2642.96 ± 1575.05 vs 1640.01 ± 1209.40, ng/ml, P = 0.024), and a tendency for higher level of plasma CFH (505.76 ± 169.28 vs 397.67 ± 179.11, μg/ml, P = 0.087). Patients with rs6677604-AA/AG had milder renal histopathological features, including total activity indices score (4.5[0, 13] vs 8[0, 19], P = 0.013), endocapillary hypercellularity (1.5[0, 3] vs 3[0, 3], P = 0.013), sub-endothelial hyaline deposits (0.5[0, 3] vs 1[0,3], P = 0.021), glomerular leukocyte infiltration (0.5[0, 1] vs 1[0, 12], P = 0.023) and tubular atrophy (1[0, 1] vs 1[0, 3], P = 0.027) than those with rs6677604-GG, which was further confirmed by the stratified analysis. The rs6677604-A was not a risk factor for patients' renal outcomes (hazard ratio=0.898; 95% CI: 0.264-3.059, P = 0.863).

CONCLUSIONS

The rs6677604-A genotype in CFH was associated with milder renal pathological features in lupus nephritis, and its protective effect on the pathogenesis of the disease remained to be elucidated.