Tonsillar antimicrobial peptide (AMP) expression profiles of periodic fever, aphthous stomatitis, pharyngitis, cervical adenitis (PFAPA) patients.

INTRODUCTION: PFAPA (periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis) is the most frequent non-infectious cause of high fever observed among the European child population. While its cause is still not yet fully identified, PFAPA patients were previously shown to have altered tonsillar microbiome composition. Our study hypothesized that this is associated with a change in antimicrobial peptide (AMP) expression levels, as in the case of Crohn's disease which is another autoinflammatory disorder.

METHODS AND MATERIALS: The tonsil specimens were isolated from seven patients with PFAPA syndrome, and six patients with group A beta-hemolytic streptococcal (GAβHS) recurrent tonsillitis. Tonsillar expression levels of human beta-defensin 1-2, cathelicidin, ribonuclease-7, and liver expressed antimicrobial peptide-1 were monitored by immunohistochemistry (IHC). Expression levels were scored using semi-quantitative analysis method and were statistically analyzed by Two-Way Repeated Measures Analysis of Variance test.

RESULTS: Our results showed no significant difference in AMP expression levels between PFAPA and GAβHS patients. Immunolocalization of human beta-defensin 1 was different between the two groups; expressed at higher levels on tonsil surface epithelium (SE) than lymphoid interior (LI) in PFAPA patient group, while this was not evident in GAβHS patients group.

CONCLUSIONS: Our results suggest that, PFAPA patients may be associated with altered AMP expression as in other autoinflammatory diseases. Future studies with subjects without any inflammatory condition are required for more precise conclusions.