Hidradenitis Suppurativa and Periodontal Diseases

The principal hypothesis of this project is the existence of an association between Hidradenitis suppurativa (HS) and periodontal diseases (PD).

The primary objective is to evaluate this association using a multicenter cross-sectional clinical approach.

The secondary objectives are:

- To study the association between the severity of PD and the severity of HS.

- To search, using saliva collected from a population with clinical signs of HS and from no HS population, proteomic and metabolomic biosignatures by liquid chromatography tandem-mass spectrometry (LC-MS), by vibrational spectroscopies and by 1H-NMR spectroscopy.

- To compare vibrational biosignatures from saliva from patients with and without HS and / or MP to determine a unique salivary spectral profile of HS patients with and without PD.

- To compare the relevance of vibrational spectroscopy versus that of LC-MS and LC-MS / MS and 1H-NMR in the analysis of salivary markers identified from an overall non-targeted spectroscopy profile.

- To analyse and to compare proteomic and metabolomic biosignatures of unstimulated saliva samples depending on the severity of HS.

Will be included patients with HS (regardless of Hurley score) followed in the dermatology department of Reims University Hospital or the Institut Pasteur in Paris, and patients without HS from the service Odontology of the University Hospital of Reims or the Bretonneau Hospital (Paris) (whatever the reason for consultation), even also from the dermatology departments.

One hundred patients with HS will be included. At the same time, 100 patients without HS will be also included. Subjects without HS will be matched to subjects with HS on age (± 5 years). Given the percentage of non-HS patients for whom periodontal disease will be diagnosed (approximately 40%), this included number of patients will demonstrate an odds ratio of 2.6 (ie a percentage of patients with periodontal disease of 63% in the group with HS) with an α risk of 5% and a power of 90%.

The primary endpoint is the presence of periodontal disease in both patients with HS and without HS.

Diagnostic of periodontal disease will be posed in consultation by a periodontist and will be determined by clinical and radiographic assessments including in this research context:

i. Gingival bleeding (Bleeding on Probing, BOP) ii. Depth of periodontal pockets using a calibrated periodontal probe iii. Clinical attachment loss iiii. Interproximal bone loss. Bone loss will be taken in consideration when the distance between the alveolar ridge and the cement-enamel junction will be ≥ 2mm. A digital orthopantomogram will be performed with or without six retroalveolar X-rays of Ramfjord teeth.

Considering the bacterial etiology of periodontal diseases, it is important to note the amount of dental plaque directly in relation with the oral hygiene level performed with the dichotomous index "Plaque Control Record".

All these indexes will be assessed at six sites per tooth corresponding to a maximum of 168 values per patient. The third molar was excluded from analysis. The reliability of clinical measurements intra and inter- periodontists was verified. In retrospect, the causes of tooth loss will be sought.

The clinical diagnosis of HS will be based on the presence of recurrent abscesses in the folds, which can be multi-site, with residual scars according to the diagnosis criteria of European guidelines published in 2015.

Secondary endpoints

- The severity of HS will be based on the score of Hurley.

- The extent and severity of PD, their progression will be posed according to the "consensus" classification of periodontal diseases (Armitage et al., 1999). Periodontitis cases were defined according to CDC-AAP case definitions updated in 2012 (Eke et al., 2015).

- Semi-quantification and characterization of spectral biosignatures will be performed on saliva samples from patients with HS and non-HS patients.

Thus, at least 5mL of unstimulated saliva will be collected from HS or non-HS patients. The pH will be measured. They will be frozen at -80°C before analysis by liquid chromatography tandem-mass spectrometry and vibrational spectroscopies and, at -20°C by 1H-NMR spectroscopy.