Petra Dytrych1, Petra Krol, Dytrych Petra1, Krol Petra2, Michaela Kotrova, Daniela Kuzilkova, Kotrova Michaela3, Kuzilkova Daniela3, Petr Hubacek, Ladislav Krol, Hubacek Petr4, Krol Ladislav3, Rami Katra, Ondrej Hrusak, Katra Rami1, Hrusak Ondrej3, Zdenek Kabelka, Pavla Dolezalova, Kabelka Zdenek1, Dolezalova Pavla2, Tomas Kalina, Eva Fronkova, Kalina Tomas3, Fronkova Eva5. 1. Department of ENT, Charles University, 2nd Faculty of Medicine, Charles University Prague and University Hospital Motol, Czech Republic. 2. Pediatric Rheumatology Unit, Department of Pediatrics and Adolescent Medicine, Charles University Prague, and General University Hospital in Prague, 1st Faculty of Medicine, Czech Republic. 3. CLIP, Department of Paediatric Haematology/Oncology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Czech Republic. 4. CLIP, Department of Paediatric Haematology/Oncology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Czech Republic; Department of Medical Microbiology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Czech Republic. 5. CLIP, Department of Paediatric Haematology/Oncology, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Czech Republic. Electronic address: eva.fronkova@lfmotol.cuni.cz.
Abstract
PURPOSE: PFAPA syndrome is a benign, recurrent inflammatory disease of childhood. Tonsillectomy is one of the therapeutic options with a yet unexplained biological mechanism. We tested whether specific lymphocyte subsets recruited from blood to human tonsils participate in PFAPA pathogenesis. METHODS: Paired tonsils/peripheral blood (PB) samples were investigated (a) from children with PFAPA that successfully resolved after tonsillectomy (n=10) (b) from children with obstructive sleep apnoea syndrome as controls (n=10). The lymphocyte profiles were analysed using 8-colour flow cytometry, immunoglobulin (IGH) and T-cell receptor (TCR) gene rearrangements via PCR and next generation sequencing; a TREC/KREC analysis was performed using qPCR. RESULTS: The PFAPA tonsils in the asymptomatic phase had a lower percentage of B-lymphocytes than controls; T-lymphocyte counts were significantly higher in PB. The percentages of cytotoxic CD8pos T-lymphocytes were approximately 2-fold higher in PFAPA tonsils; the transitional B cells and naïve stages of both the CD4pos and CD8pos T-lymphocytes with a low expression of PD-1 molecule and high numbers of TREC were also increased. With the exception of elevated plasmablasts, no other differences were significant in PB. The expression levels of CXCL10, CXCL9 and CCL19 genes were significantly higher in PFAPA tonsils. The IGH/TCR pattern showed no clonal/oligoclonal expansion. DNA from the Epstein-Barr virus, Human Herpervirus-6 or adenovirus was detected in 7 of 10 PFAPA tonsils but also in 7 of 9 controls. CONCLUSIONS: Our findings suggest that the uninhibited, polyclonal response of newly derived lymphocytes participate in the pathogenesis of PFAPA. Because most of the observed changes were restricted to tonsils and were not present in PB, they partly explain the therapeutic success of tonsillectomy in PFAPA syndrome.
PURPOSE: PFAPA syndrome is a benign, recurrent inflammatory disease of childhood. Tonsillectomy is one of the therapeutic options with a yet unexplained biological mechanism. We tested whether specific lymphocyte subsets recruited from blood to human tonsils participate in PFAPA pathogenesis. METHODS: Paired tonsils/peripheral blood (PB) samples were investigated (a) from children with PFAPA that successfully resolved after tonsillectomy (n=10) (b) from children with obstructive sleep apnoea syndrome as controls (n=10). The lymphocyte profiles were analysed using 8-colour flow cytometry, immunoglobulin (IGH) and T-cell receptor (TCR) gene rearrangements via PCR and next generation sequencing; a TREC/KREC analysis was performed using qPCR. RESULTS: The PFAPA tonsils in the asymptomatic phase had a lower percentage of B-lymphocytes than controls; T-lymphocyte counts were significantly higher in PB. The percentages of cytotoxic CD8pos T-lymphocytes were approximately 2-fold higher in PFAPA tonsils; the transitional B cells and naïve stages of both the CD4pos and CD8pos T-lymphocytes with a low expression of PD-1 molecule and high numbers of TREC were also increased. With the exception of elevated plasmablasts, no other differences were significant in PB. The expression levels of CXCL10, CXCL9 and CCL19 genes were significantly higher in PFAPA tonsils. The IGH/TCR pattern showed no clonal/oligoclonal expansion. DNA from the Epstein-Barr virus, Human Herpervirus-6 or adenovirus was detected in 7 of 10 PFAPA tonsils but also in 7 of 9 controls. CONCLUSIONS: Our findings suggest that the uninhibited, polyclonal response of newly derived lymphocytes participate in the pathogenesis of PFAPA. Because most of the observed changes were restricted to tonsils and were not present in PB, they partly explain the therapeutic success of tonsillectomy in PFAPA syndrome.