Ingrained Insight into Nasal Polyposis; Role of Human Papillomavirus: An Indian Study

Abstract

Nasal polyposis (NP) are benign lesion of nasal cavity, affecting up to 1–4% of population. It is known to have up to 70% recurrence rate. The underlying pathophysiology is still undetermined. Recent literatures have thrown light on the viral aetiology for NP. To our knowledge this is the first Indian study done, that aims to evaluate the prevalence of Human papillomavirus (HPV) in NP. It was a prospective case control study done among 40 individuals with NP and 40 healthy controls in a tertiary care centre. All the patients were subjected to routine clinical evaluation, investigations prior to proposed surgeries. The mucosal samples after the surgery were subjected to HPV DNA analysis by RT-PCR. Among the cases, the male to female ratio was 1.3:1. The mean age of patients with NP was 39 ± 14.6. The mean serum IgE levels among the case were 154 IU/ml and was significantly higher as compared to controls. Other inflammatory markers such as absolute eosinophil count, erythrocyte sedimentation rate, and neutrophil to leukocyte ration were found to be not significant. There was no HPV DNA detected among both case as well as controls. There seems to be strong association of IgE and NP, suggesting an IgE mediated pathway for its Causation. There is no association of HPV in NP.

Introduction

Nasal polyposis (NP) is defined as polyp presents in the nasal cavity with a grape-like appearance, having a ‘body’ and a ‘stalk’. ‘The surface is smooth and the colour is more yellow than the pink mucous membrane’ [1]. The term ‘polyp’ originates from a greek word ‘polypous’, meaning many footed (poly, many; pous, footed), but in reality the polyp has only one ‘foot’ i.e. stalk. NP is characterized by the occurrence of multiple polyps is most correctly named nasal polyposis and, strictly speaking, it is not a nasal but a sinonasal disease [1].

Nasal polyposis was recorded in the literature dating as old 4000 years ago. Over the years, there has been significant advances in the understanding of the disease, its aetiology, pathogenesis, and management.

It was assumed that allergic rhinitis predisposes to nasal polyposis, since both the disease had symptoms of watery rhinorrhoea and mucosal swelling, although epidemiological studies showed very little evidence for the same. Studies showed that the prevalence of nasal polyposis in allergic rhinitis was only 1–2% of the patients with positive allergy skin prick test [2]. Further, it was found that there was no correlation between presence of total and specific IgE in the polyp and the positive skin prick test, but it showed correlation with the total eosinophil counts, Hence it was thought to be due to the local allergic reaction [3]. All though the theory for the cause for the disease has evolved over the years, there is still controversy regarding its aetiology and nevertheless, we still face recurrence of the disease and the need for repeated surgical procedure. Thus, to this day the quest for the cause and the cure for the nasal polyp remains an important goal. In this study, we have tried to investigate the association of known etiological factors with NP occurrence and to find the incidence of human papilloma virus (HPV) with NP.

Methods

A prospective case control study was done in a tertiary care centre during 2017–2019, with 40 cases of NP and 40 controls with other nasal pathology, who consented for the proposed surgery and the study. Institutional ethics committee approval was taken prior to the commencement of the study (attached in the annexure). For case group, all patients with ethmoidal polyposis and antrochoanal polyp were included and exclusion criteria was, patients with inverted papilloma, sinonasal cancer, those who did not consent for the study and patients less than ten years of age. And for controls individuals with other sinonasal pathology such as deviated nasal septum, hypertrophied inferior turbnate and chronic sinusitis who consented for surgical management were included. Individuals of both the group were subjected to investigations which included serum IgE, absolute eosinophil count (AEC), neutrophil to lymphocyte ratio (NLR), and HPV DNA analysis using reverse- transcriptase polymerase chain reaction (RT-PCR) method, apart from the routine blood investigations done for pre-anaesthetic check-up.

HPV DNA Detection and Genotyping

The fresh tissue samples from both the groups were obtained, for cases the tissue sample of polyps and for controls biopsy of normal mucosa from either inferior turbinate or middle meatal region were taken. These samples were outsourced from our institute to lab with PCR facility in a reverse cold chain. The tissue sample were processed within 48–72 h from the time of surgery. The PCR technique was performed as already explained in the literature [4].

The statistical analysis was done using the SPSS v21.0 software.

Results

Total of 40, gender and age match cases and controls were chosen. There were total of 17 females and 23 males in both the groups. The mean age in case was 39.9 ± 14.6 years, were as in control was 35.5 ± 13.5 years. The participants were from various background and socioeconomic groups, no significant association of NP with occupation was noted.

Headache, nasal discharge, sneezing, post nasal discharge were among the most common symptoms of cases of NP (Fig. 1).

Fig. 1.

Showing the distribution of symptoms among cases and control

The distribution of comorbidities (diabetes mellitus, hypertension, bronchial asthma, and other allergic disease) and habits (smoking tobacco and alcohol consumption) are shown in Fig. 2. There was no statically significant association of comorbidities or habits on occurrence of NP.

Fig. 2.

Showing the prevalence of comorbidities and habits among the cases and control

All patients underwent thorough otolaryngology assessment, radiological evaluation and were subjected to routine blood investigations prior to the proposed surgeries.

Lund Mackay radiological staging was done for all the cases [5]. Maxillary sinus and ethmoid sinus were the most commonly involved sinuses. The median Mackay Lund score in our study was 12.75 + − 5.8. The lowest score was 5 and highest score was 24.

The median level of AEC among both the groups was not significantly different, among the case the median AEC value was 365 cell/dl (200-478 cells/dl) as compared to 280 cells/dl (200–575 cells/dl) among the controls (Mann–whitney U test p of 0.9). Similarly, the median NLR among case was 2.27 (1.01–7.84) and among controls was 2.16 (0.96–10.9) (Mann–whitney U test p value of 0.9) was not statistically significant.

There was statistically significant difference in the level of non-specific IgE levels among the case and controls (Mann–Whitney test p = 0.003).The median level of non-specific IgE level was 154 IU/ml (74.80–822 IU/ml) in cases and 72.70 IU/ml (45.60–193.1 IU/ml).

On HPE the polyp specimens were classified into eosinophilic polyp and non-eosinophilic polyp. The criteria to categorize a polyp to be eosinophilic polyp in our institute was to have minimum eosinophilic proportion of 11% in the tissue sample. We noticed that majority of NP were eosinophil predominant histopathological variant, accounting for 77.5% (31/40).

The operative specimens were sent for HPV DNA detection using the RT-PCR and DNA phenotyping (both high risk and low risk strains) (Fig. 3).There was no positive result for the HPV DNA in both the groups.

Fig. 3.

Showing the operative nasal polyp specimen being sent for HPV DNA analysis

Discussion

Chronic rhinosinusitis (CRS) is now recognised to affect about 10% of the adult population in industrialized countries. From surveys based on Short Forms, CRS has shown to negatively affect several aspects of a person’s quality of life and a greater extent on the social functioning than chronic heart failure, back pain, or chronic respiratory problems. Phenotypically CRS has been classified as CRS without nasal polyposis (CRSsNP) and CRS with nasal polyp (CRSwNP) [6].

The etiopathogenesis for CRSwNP has been a topic of controversies, and no definite hypothesis for disease has so far proven to be satisfactory. Although the strong association with Th2 basis for the disease has been suggested from its characteristic disease recurrence after pharmacotherapy as well as with surgery and lower airway comorbidity in affected patients. There are mounting evidence that NP is probably a clinical manifestation of not one but due to multiple possible co existing immunologic pathways. This study we attempted to look into the possible viral aetiology of NP.

This study was conducted among age and gender matched 40 cases of NP who underwent nasal surgery and controls who underwent nasal surgery for other sinonasal pathology. There were total of 17 (42.5%) females and 23 (57.5) males in both the groups. We noticed slight male preponderance among cases of NP although this was not statistically significant (p = 0.8 Chi square T test). Male to female ratio in our study was 1.3:1, which was different from the other studies, which showed higher ratios of 2:1 [7–9].

In our study, the mean age amongst the cases of NP was 39.9 ± 14.6. Youngest case of NP being a 12 year old and oldest case being a 70-year-old female. The most common age group of clinical presentation for NP was 20-30 years (10/40 25%). This finding was similar to a study done by Jahromi et al. [10] who reported the average age of incidence of NP to be 39.49 ± 16.63 years (7–79 years) and the most common age of occurrence was during the second decade of life. Further, studies have reported statistical association between the Neutrophil to Leukocyte ratio (NLR). Sharma et al. [11] in their study noted that the mean NLR was significantly lower and was 1.5 ± 0.4 among the cases of NP, were as it was 1.8 ± 0.5 among the controls and with the p value of 0.0005 and was strongly statistically significant. Meanwhile Apuhan et al. [12] reported that the NLR was significantly higher among the NP as compared to the normal controls. The mean NLR in their study was 1.67 (1.1–11.9) with p value of 0.006.

In contrast to the above two studies, our study the NLR was not significantly different among the study groups, the median NLR among case was 2.27 (1.01–7.84) and among controls was 2.16 (0.96–10.9) (p value = 0.9).

The median level of AEC among both the groups was not significant different, among the case the median AEC value was 365 cell/dl (200–478 cells/dl) as compared to 280 cells/dl (200–575 cells/dl) among the controls (Mann–whitney test p = 0.9). Chaithanya KV in his study reported the incidence of elevated AEC amongst 80.43% cases of NP. Although he added that this increase in AEC was only mild in majority of the cases. And was not purely dependent on the allergic etiology of disease. Hence he claimed the increased Eosinophil count alone cannot be pointed as the etiological factor for NP [9].

In our study there was statistically significant difference in the level of non-specific IgE levels among the case and controls (Mann–Whitney test p = 0.003). The median level of non-specific IgE level was 154 IU/ml (74.80–822 IU/ml) in cases and 72.70 IU/ml (45.60–193.1 IU/ml). The mean IgE level was similar the study done by Drake et al. [13] they found the mean IgE level in NP was 100U/ml (6.25–3200U/ml). Krishna VC reported elevated IgE among 69.67% of cases of NP [9]. The surgical samples in our study were grouped into eosinophilic polyps or non-eosinophilic polyps. Majority of the samples were eosinophilic predominant polyps.

HPV-DNA Analysis in Nasal Polyp

The operative specimens were sent for HPV DNA detection using the RT-PCR and also DNA phenotyping was done for all the cases as well controls. There was no positive result for the HPV DNA test in both the groups.

The literature review for incidence of HPV is shown in the Table 1.

Table 1.

Prevalence of HPV in global literature

S. no	Authors	Study sample size	Incidence of HPV	Most commonest strain
1	Pei et al. [16]	204	82/204 (40.2%)	HPV 11
2	Knor et al. [4]	205	46/205 (22.4%)	HPV 16
3	Rizzo et al. [15]	20	10 (50%)	HPV 11
4	Jing et al. [17]	70	19/70 (27.4%)	HPV 5
5	Zaravinosis et al. [18]	23	3 (13%)	–
6	Koçoğlu et al. [19]	30	4/30 (13.3%)	HPV 16
7	Ioannidis et al. [20]	91	0/91 (0%)	–
8	Becker et al. [21]	20	0/20 (0%)	–
9	Sham et al. [22]	48	0/48 (0%)	–
10	Hoffmann et al. [23]	20	0/20 (0%)	–
11	Present study	40	0/40 (0%)	–

Different techniques of HPV detection were used by authors in the published literature. Polymerase chain reaction was the most commonly employed technique. Few authors tried flow cytometry and immunohistochemistry as well along with PCR [4, 14].

The presence of HPV DNA could be proven only with PCR so far, probably due to the low viral load. Knor et al. also stated that p16 component of HPV seems to not play any role in NP [4].

Conclusion

In our study there was no incidence of HPV in both 40 cases of NP as well 40 healthy controls. In our study there was strong statistical significance between the serum non-specifics IgE with the NP. We didn’t find any statistical significance of inflammatory markers such as AEC and NLR etc. with NP. Hence we conclude that there is no association of HPV with NP and that IgE mediated response pathway could be responsible for the occurrence of NP.

Funding

This study has not received any funding.

Compliance with Ethical Standards

Conflict of interest

All the authors declare they have no conflicts of interest.

Ethical Clearance

Informed consent was taken and the study is approved by the institutional ethic committee.