PAD diseases have a challenging features and classification, we investigate salivary protein composition of our patients in order to reach more about the link between innate and antibody response.
We applied a top-down proteomic approach to compare, qualitatively and quantitatively, the acid soluble fraction of the salivary proteome from CVID patients and from adult healthy controls by an RP-HPLC-ESI-MS apparatus. 23 patients with predominantly antibody deficiency, 6 males and 16 females were enrolled and compared with 30 healthy controls. We focused on proteins and peptides soluble in acid solution, which were acidic proline-rich proteins (aPRPs), histatins (Hst-1, Hst-3, Hst-3 1-24, Hst-3 1-25), thymosins β4 and β10, α-defensins 1, 2, 3, and 4, statherin, P-B peptide, cystatins A, B, C, D and S, S100A7, A8, A9, and A12, such as all the known proteoforms derived by post-translational modifications (phosphorylation, oxidation, proteolytic cleavage, acetylation).
Patients exhibited lower abundance of α-defensins 1-4, cystatins S1 and S2, and higher abundance of glutathionylated cystatin B and cystatin SN than controls. Patients could be clustered in two groups on the basis of different levels of SN, S1 and S2, suggesting that these proteins may play different roles in the disease
Quantitative variations of these pro-inflammatory and antimicrobial peptides/proteins may be related to immunodeficiency and infectious condition of the patients. The high incidence of tumors in the group with the highest level of SN, which is recognized as tumoral marker, appeared an intriguing result deserving of future investigations.