Absence or mislocalization of DNAH5 is a characteristic marker for motile ciliary abnormality in nasal polyps

OBJECTIVE

Motile cilia impairment is a common condition in patients with chronically inflamed airways, such as is seen in nasal polyps (NPs). The mechanism underlying this pathogenic condition is complex and not fully understood.

METHODS

We investigated the presence and localization of dynein axonemal heavy chain 5 (DNAH5) in motile cilia using immunofluorescence staining in paraffin-embedded nasal biopsies from NPs (n = 120) and inferior turbinate mucosa (n = 35) of healthy controls. We also performed single-cell staining on cytospin samples (NP = 5, control = 5). Three patterns of DNAH5 localization are defined, including pattern A (presence throughout the axoneme), pattern B (undetectable in the distal part of the axoneme), and pattern C (completely missing throughout the entire axoneme). We developed a semiquantitative scoring system for which 0 = (pattern A > 70%); 1 = (patterns A + B > 70%); and 2 = (pattern C ≥ 30%) in each high-power field (5 fields per sample).

RESULTS

Based on our DNAH5 scoring system, the median (1st and 3rd quartile) score was 0.3 (0.2 and 0.4) for samples from controls, and 1.1 (0.6 and 1.6) for samples from NPs in paraffin specimens (P < 0.001). The DNAH5 score had a significant positive relationship with the Lund-Mackay computed tomography score (r = 0.329, P = 0.005) and was higher in patients with eosinophilic NPs (P = 0.006). For cytospin samples, the mean percentage of patterns A, B, and C were 74%, 14%, and 12% in controls, and 48%, 20%, and 32% in NPs, respectively.

CONCLUSION

Our results suggest that the absence or mislocalization of DNAH5 from motile cilia is a common and potentially important pathological phenomenon in chronically inflamed airway epithelium.

LEVEL OF EVIDENCE

NA. Laryngoscope, 128:E97-E104, 2018.

Increase of poorly proliferated p63+ /Ki67+ basal cells forming multiple layers in the aberrant remodeled epithelium in nasal polyps

BACKGROUND

Aberrant epithelial remodeling with the ectopic expression of p63 (basal cell markers) is an important pathologic phenomenon seen in chronically inflamed airway epithelium such as in nasal polyps (NPs).

METHODS

Biopsies were obtained from 55 NP patients and 18 healthy controls (inferior turbinate). Among NP patients, 15 were treated with oral and nasal steroids, so that two sets of NP biopsies were taken before and after the treatments. p63, Ki67, type IV β-tubulin, and cell cycle markers were investigated in these specimens.

RESULTS

The number of p63⁺ cells is significantly higher in both hyperplastic (1.53-fold, P < 0.0001) and squamous metaplastic (2.02-fold, P < 0.0001) epithelium from NPs than from healthy controls. There are three types of proliferative basal cells (p63⁺ /Ki67⁺ ) which are in different phases of the cell cycle, such as G1 phase (type I cells), S to G2 phase (type II cells), and mitosis (type III cells). Of importance, some type I cells may arrest after proliferation although they may still be p63⁺ /Ki67⁺ . In healthy epithelium, the ratio of the type I and II cells is almost 50:50. However, less type II cells are found in hyperplastic epithelium (34.85%, P = 0.012) and in squamous metaplastic epithelium (30.77%, P = 0.02) together with the presence of type III cells (3.45%, P = 0.01). These findings were not changed after steroid treatments.

CONCLUSIONS

An increase of poorly proliferated basal cells forming multiple layers, which may stain for basal cell markers but does not form a proper epidermal barrier, is an important histopathologic phenomenon in aberrant remodeled epithelium of NPs.