Absence of circulating immune complexes containing DNA in hemodialysed sera

Area of Science:

• Nephrology
• Immunology
• Molecular Biology

Background:

• Previous studies reported DNA and anti-DNA presence in hemodialysis patients.
• An improved detection technique was employed to re-evaluate these findings.

Purpose of the Study:

• To investigate the incidence of antibodies to single-stranded DNA (ss-DNA) and native DNA (n-DNA) in renal patients undergoing maintenance hemodialysis.
• To search for evidence of DNA-anti-DNA circulating immune complexes (CIC) formation in these patients.

Main Methods:

• Detection of antibodies to ss-DNA and n-DNA using an improved technique.
• Quantification of CICs using Raji-Raji-linked immunosorbent assay (RIA) and C1q-binding assay (BA).
• DNase digestion assays on patient sera and in vitro DNA-anti-DNA complexes.

Main Results:

• A low incidence of antibodies to n-DNA was observed in both dialysed (2/53) and non-dialysed (1/25) renal patients.
• Circulating immune complexes (CICs) were detected in 17/53 dialysed and 6/25 non-dialysed patients, with no significant difference between groups.
• DNase digestion did not significantly alter CIC levels in dialysed patients' sera, unlike in Systemic Lupus Erythematosus (SLE) sera or in vitro complexes.

Conclusions:

• The formation of circulating DNA-anti-DNA complexes does not appear to be the reason for the low incidence of antibodies to n-DNA in the sera of patients on maintenance hemodialysis.
• The improved detection technique revealed a lower prevalence of these antibodies than previously reported.