Retinal drusen are more common and larger in SLE with renal impairment

Drusen and Other Retinal Findings in People With IgA Glomerulonephritis

PURPOSE

Retinal drusen have been described in people with IgA nephropathy. We examined the frequency of drusen in IgA nephropathy and compared their location and composition with those for drusen in age-related macular degeneration.

DESIGN

Immunohistological case series of eyes of patients with IgA nephropathy, and a comparison eye with age-related macular degeneration.

METHODS

Donor eyes from 4 individuals (3 male, 1 female, aged 40-80 years) with biopsy-proven IgA nephropathy and kidney failure were examined for the presence of drusen, and location and composition using antibodies for vitronectin, IgA, IgM, IgG, C3, and C1q. Results were compared with those for drusen in macular degeneration without IgA nephropathy.

RESULTS

All 4 donors had sparse, subretinal pigment epithelium drusen of 55-65 mm diameter that stained for vitronectin but not for IgA or complement. All donors had retinal capillaries and choriocapillaris staining for IgA. The youngest donor (female, 40) had rare deposits in the outer nuclear layer that stained for IgA, but not for vitronectin. The oldest donor (male, 82) had large cystlike spaces in the inner nuclear and plexiform layers, and smaller cysts in the outer nuclear layer, with no staining for IgA or complement.

CONCLUSIONS

Retinal drusen are uncommon in IgA nephropathy, even with kidney failure. Drusen in IgA nephropathy resemble drusen found in age-related macular degeneration. IgA-staining deposits in the outer nuclear layer were likely due to systemic deposition of IgA and complement activation. The nature of cystic spaces is unknown. Further analysis of the retinas of people with glomerulonephritis is recommended.

Associations Between Autoimmune Disease and the Development of Age-Related Macular Degeneration

Purpose

The pathogenesis of age-related macular degeneration (AMD) likely implicates the dysregulation of immune response pathways. Several studies demonstrate that the pathogenic elements of AMD resemble those of autoimmune diseases, yet the association between AMD development and most autoimmune diseases remain unexplored.

Methods

We conducted a case-control analysis of patients ages 55 and older with new-onset International Classification of Diseases (ICD) coding of dry, wet, or unspecified AMD between 2005 and 2019 in the Merative MarketScan Commercial and Medicare Databases. The diagnosis of an autoimmune disease was defined by an outpatient or inpatient claim with a relevant ICD code in the 12 months before the index visit. Conditional multivariable logistic regression, adjusted for AMD risk factors, was used to calculate odd ratios and 95% confidence intervals.

Results

We identified 415,027 cases with new-onset ICD coding for AMD matched with propensity scores to 414,853 controls. In total, 16.1% of cases and 15.9% of controls were diagnosed with any autoimmune disease. The diagnosis of any autoimmune disease did not affect the odds of new-onset ICD coding for AMD in multivariable regression (OR = 1.01; 95% CI, 0.999-1.02). Discoid lupus erythematosus (OR = 1.29; 95% CI, 1.12-1.48), systemic lupus erythematosus (SLE) (OR = 1.21; 95% CI, 1.15-1.27), giant cell arteritis (OR = 1.19; 95% CI, 1.09-1.30), Sjogren's syndrome (OR = 1.17; 95% CI, 1.09-1.26), and Crohn's disease (OR = 1.13; 95% CI, 1.06-1.22) increased the odds of a new-onset ICD coding for AMD.

Conclusions

Most autoimmune diseases do not affect the odds of developing AMD but several common autoimmune disorders such as SLE and Crohn's disease were associated with modestly increased odds of AMD. Further studies are needed to validate and investigate the underlying mechanisms of these associations.

Increased retinal drusen in IgA glomerulonephritis are further evidence for complement activation in disease pathogenesis

Drusen are retinal deposits comprising cell debris, immune material and complement that are characteristic of macular degeneration but also found in glomerulonephritis. This was a pilot cross-sectional study to determine how often drusen occurred in IgA glomerulonephritis and their clinical significance. Study participants underwent non-mydriatic retinal photography, and their deidentified retinal images were examined for drusen by two trained graders, who compared central drusen counts, counts ≥ 10 and drusen size with those of matched controls. The cohort comprised 122 individuals with IgA glomerulonephritis including 89 males (73%), 49 individuals (40%) of East Asian or Southern European ancestry, with an overall median age of 54 years (34-64), and median disease duration of 9 years (4-17). Thirty-nine (33%) had an eGFR < 60 ml/min/1.73 m² and 72 had previously reached kidney failure (61%). Overall mean drusen counts were higher in IgA glomerulonephritis (9 ± 27) than controls (2 ± 7, p < 0.001). Central counts ≥ 10 were also more common (OR = 3.31 (1.42-7.73, p = 0.006), and were associated with longer disease duration (p = 0.03) but not kidney failure (p = 0.31). Larger drusen were associated with more mesangial IgA staining (p = 0.004). Increased drusen counts were also present in IgA glomerulonephritis secondary to Crohn's disease but not with Henoch-Schonlein purpura. The finding of retinal drusen in IgA glomerulonephritis is consistent with complement activation and represents a model for better understanding glomerular immune deposition and a supporting argument for treatment with anti-complement therapies.