Infrared Saliva Analysis of Psoriatic and Diabetic Patients: Similarities in Protein Components

Psoriasis is a chronic skin disease which is very common in the population and requires frequent clinical and pharmacological treatment. In the following, a study based on Fourier transform infrared spectroscopy analyzing saliva proteomic components in psoriatic patients against diabetic patients and a control group is presented. Clinical analysis showed a prominent amide II band, at around 1545 cm(-1), and the composition of the amide I band, at around 1647 cm(-1), allowing us to distinguish the infrared salivary signature of psoriatic and diabetic patients from the control group and even from patients with different kinds of psoriasis. Moreover, results highlighted existing differences in the secondary structure composition of proteins between psoriatic and diabetic patients as compared to the control group. In fact, the saliva spectra of the control group and that of the palmoplantar psoriatic patients differ from plaque psoriasis and diabetic patient spectra because of the absence of the amide II band and the presence of different secondary protein-structure conformations.