Chronic Rhinosinusitis: T2r38 Genotyping and Nasal Cytology in Primary Ciliary Dyskinesia

Abstract

Objectives: Chronic rhinosinusitis (CRS) is a major hallmark of primary ciliary dyskinesia (PCD). We investigated the possible correlation between some severity markers of CRS and several clinical features of the disease. We further studied the bitter taste receptor TAS2R38 polymorphisms to identify the genotypes associated with more severe disease.

Methods: We included 39 adult PCD patients with (CRSwNP) and without nasal polyposis (CRSsNP); a sample for nasal cytology was obtained and clinical cytological grading (CCG) was determined. The SNOT-22 and Lund-Mackay scores were recorded. A sample of DNA was extracted from peripheral blood to investigate TAS2R38 polymorphisms.

Results: CRSwNP patients had features of more severe disease: indeed, they had statistically significantly higher frequency of previous sinus surgery, higher SNOT-22, LM scores, and CCG than CRSsNP patients. Upon genotyping of TAS2R38 polymorphisms, we observed that the AVI-AVI genotype, associated to homozygous nonfunctional bitter TAS2R38 receptor, was more prevalent among CRSwNP (100%) than in CRSsNP patients (0%); furthermore, AVI-AVI subjects showed statistically significantly worse SNOT-22 and CCG scores than PAV-PAV and PAV-AVI subjects. The group of AVI-AVI patients also had more frequent respiratory exacerbations, Gram-negative infections, and Pseudomonas aeruginosa colonization than PAV-PAV and PAV-AVI patients.

Conclusion: Our findings indicate for the first time that PCD patients with CRSwNP display a more severe disease than those with CRSsNP. Genotyping of TAS2R38 polymorphisms demonstrated that in PCD patients, the AVI-AVI genotype is strikingly more prevalent among CRSwNP than in CRSsNP, while the PAV-PAV genotype might be protective against Gram-negative infections and respiratory exacerbations.

Level of evidence: 3 Laryngoscope, 133:248-254, 2023.

Keywords: TAS2R38; bitter taste receptors; chronic rhinosinusitis; nasal cytology; primary ciliary dyskinesia.

Fig. 1

(A) Typical nasal endoscopy of a PCD patient with relapsing CRSwNP where it can be observed a complete obliteration of the left middle meatus by nasal polyps covered with dense purulent secretions; (B) axial CT scan of a patient with relapsing CRSwNP documenting complete maxillary and middle meatus opacification on both sides. CT = computed tomography; CRSwNP = chronic rhinosinusitis with nasal polyps; PCD = primary ciliary dyskinesia.

Fig 2

Examples of nasal cytology in PCD: (A) the inflammatory picture is dominated by neutrophils; (B) a mixed inflammation with neutrophils and eosinophils; (C) neutrophils and associated bacteria. PCD = primary ciliary dyskinesia.