Evidence for intranasal antinuclear autoantibodies in patients with chronic rhinosinusitis with nasal polyps

Abstract

Background: Chronic rhinosinusitis (CRS) with nasal polyps is an inflammatory condition of the nasal passage and paranasal sinuses characterized by T(H)2-biased inflammation with increased levels of B-cell activating factor of the TNF family (BAFF), B lymphocytes, and immunoglobulins. Because high levels of BAFF are associated with autoimmune diseases, we assessed for evidence of autoimmunity in patients with CRS.

Objectives: The objective of this study was to investigate the presence of autoantibodies in sinonasal tissue from patients with CRS.

Methods: Standardized nasal tissue specimens were collected from patients with CRS and control subjects and assayed for immunoglobulin production, autoantibody levels, tissue distribution of immunoglobulins, and binding potential of antibodies in nasal tissue with a multiplexed autoantibody microarray, ELISA, and immunofluorescence.

Results: Increased levels of several specific autoantibodies were found in nasal polyp tissue in comparison with levels seen in control tissue and inflamed tissue from patients with CRS without nasal polyps (P < .05). In particular, nuclear-targeted autoantibodies, such as anti-dsDNA IgG and IgA antibodies, were found at increased levels in nasal polyps (P < .05) and particularly in nasal polyps from patients requiring revision surgery for recurrence. Direct immunofluorescence staining demonstrated diffuse epithelial and subepithelial deposition of IgG and increased numbers of IgA-secreting plasma cells not seen in control nasal tissue.

Conclusions: Autoantibodies, particularly those against nuclear antigens, are present at locally increased levels in nasal polyps. The presence of autoantibodies suggests that the microenvironment of a nasal polyp promotes the expansion of self-reactive B-cell clones. Although the pathogenicity of these antibodies remains to be elucidated, the presence of increased anti-dsDNA antibody levels is associated with a clinically more aggressive form of CRS with nasal polyps requiring repeated surgery.

Figure 1

Total and anti-dsDNA levels in nasal tissue. A. Total IgG; B. Total IgA. Anti-dsDNA levels of C. IgA and D. IgG subtypes. The dashed line represents the mean +3SD of the levels of autoantibodies found in control nasal tissue. All analyses had a significant Kruskal-Wallis test, * signifies a significant post-hoc Dunn’s test. Results are normalized to total protein levels.

Figure 2

Correlation of anti-dsDNA antibody levels. A. The level of Anti-dsDNA IgG normalized to Total IgG levels. This analysis had a significant Kruskal-Wallis test but post-hoc testing was non-significant. B. Anti-dsDNA IgG levels did not correlate with Total IgG levels in nasal polyp tissue. C. Conversely, anti-dsDNA IgG levels correlated with Total IgG in nasal tissue from control and CRSsNP patients. D. Anti-dsDNA IgG and IgA levels in nasal polyps are positively correlated. In one patient (marked by a “o”), no detectable total IgA was measured in the patient’s nasal tissue raising the possibility of an IgA deficiency and we excluded this sample from the analysis in D. Except for A., all results are normalized to the total protein concentration.

Figure 3

Correlation between anti-dsDNA levels in nasal polyps and clinical parameters. A. The anti-dsDNA IgG in recurrent nasal polyps was elevated compared to those undergoing initial nasal polyp surgery. B. Total immunoglobulin levels were not correlated with surgical status. C. Frequency of elevated anti-dsDNA IgG in different subgroups. Anti-dsDNA antibodies are not differentially found in D. asthmatics and E. atopic patients. F. Higher grade polyps have higher anti-dsDNA levels. All results are normalized to total protein levels.

Figure 4

Immunofluorescence of nasal tissue. A. IgG direct immunofluorescence in a nasal polyp (green fluorescence) and B. control nasal uncinate tissue showing scattered plasma cells (red arrow). Indirect Immunofluorescence of control uncinate tissue incubated with: C. tissue extract from control patient and D. nasal polyp extract from a patient with elevated level of anti-dsDNA autoantibodies. Nuclei were counterstained with DAPI (blue fluorescence), IgG was labeled using anti-IgG (green fluorescence). Normalized anti-dsDNA IgG levels found in each of the tissue extracts (numbers in white). E. Hep-2 assay on nasal polyp extract from the same patient. F. Nuclear staining intensity of samples analyzed on Hep-2 assay.