Association of anti-C1q antibodies, adiponectin and HLA II genotype in Colombian patients with systemic lupus erythematosus with lupus nephritis

Objective

To establish associations between the development of lupus nephritis (LN) and the expression of antibodies against C1q (anti-C1q) and serum adiponectin as these biomarkers have been previously postulated to be associated with the presence of LN.

Materials and methods

A case–control study nested in a cohort was chosen. Patients with SLE with renal involvement were included. Measurement of antibodies against C1q, levels of adiponectin, and HLA expression DRB1 and DQB1 were evaluated. We searched for possible associations between the measured biomarkers and allelic HLA types found.

Results

One hundred and six patients were recruited with LN with a mean age of 35 years. Mean adiponectin levels were 16.9 μg/mL, and 60% of patients presented anti-C1q positivity. HLA DRB1*0404 and DRB1*1101 are protective factors for LN (OR: .42, p = .0030 and OR: 0.49, p = .046 respectively). HLA DRB1*0701 (OR: 3.15, p = .0452) and DRB1*0802 (OR: 8.3, p = .020) are susceptibility factors for LN. There was a tendency for association between anti-C1q positivity and high levels of adiponectin with type IV LN (OR 2.3 [95% CI: 0.68–8.2] and (OR: 2.67 [95% CI: .76–9.9] respectively). There was a tendency for association between anti-C1q positivity and HLA expression DRB1*0701 (OR 2.7 [95% CI: .81–11.5]), as well as high levels of adiponectin and HLA expression DRB1*0404 (OR 3.03 [95% CI: .92–12.8]). No association was found between anti-C1q and adiponectin with the expression of HLA DRB1*1501. There was positive correlation between levels of anti-C1q and the activity index in renal biopsy.

Conclusions

In the Colombian population there is a tendency for association of anti-C1q with the expression of HLA DRB1*07; however, the expression of other HLA II genes known as risk factors for LN, was not associated with the expression of anti-C1q, adiponectin or any specific type of LN.