Sergio Amarri UO Pediatria Azienda Ospedaliera Reggio Emilia Anticorpi Anti Gliadina Deamidata: un nuovo utile marker per la malattia celiaca Sergio Amarri UO Pediatria Azienda Ospedaliera Reggio Emilia

Sintomi tipici di malattia celiaca diarrea vomito distensione addominale perdita di peso pallore anoressia magrezza edemi irritabilità

Manifestazioni extraintestinali Dermatite erpetiforme Anemia sideropenica di ndd Bassa statura Ritardo puberale Infertilità ed aborti ricorrenti Alopecia areata Stomatite aftosa Ipoplasia smalto dentario Ipertransaminasemia di ndd Epilessia farmaco-resistente, atassia , polineurite Osteoporosi Miocardiopatia dilatativa Artriti

Quadri clinici e malattie associate Tiroidite di Hashimoto Diabete tipo I: 3 – 8 % Sindrome Down: 5 – 12 % Sindrome di Turner Sindrome di Sjogren Deficit IgA Sclerosi multipla Cirrosi biliare primitiva

Sensibilità e Specificità Sensibilità = a/(a+c) Specificità = d/(b+d) Alta sensibilità = pochi falsi negativi (c)! Alta specificità = pochi falsi positivi (b)!

Combinazioni marker celiachia EMA-IgA AGA-IgA. AGA-IgG. Diagnosi Combinazioni marker celiachia EMA-IgA AGA-IgA* AGA-IgG* Diagnosi anti-tTG IgA anti-tTG IgG * AGA < 2 anni di età. Anti-tTG positivi conferma EMA

Utilità marker celiachia Anti-transglutaminasi IgA (il più utile) Limiti: deficit di IgA e primi due anni di vita EMA IgA (meno sensibile e più specifico della tTG si usa per conferma) Limiti: costoso e legato all’interpretazione dell’operatore Anti-transglutaminasi IgG (poco accurato) AGA IgA (utile sotto i due anni di vita) AGA IgG (di scarsa utilità)

DGP

Celiac Disease NEJM 2007; 357:1731-1743 Peter H. R Celiac Disease NEJM 2007; 357:1731-1743 Peter H.R. Green and Christophe Cellier

Lewis&Scott. Deamidated gliadin and tTG compared as screening for coeliac disease. Aliment Pharmacol 2010 IgA - DGP IgA - tTG

Lewis&Scott. Deamidated gliadin and tTG compared as screening for coeliac disease. Aliment Pharmacol 2010 IgA - DGP IgA - tTG

Combination testing for antibodies in the diagnosis of coeliac disease: comparison of multiplex immunoassay ELISA methods. Aliment Pharmacol 2008; 28: 805-13 Test κ- Statistics Sensitivity (%) Specificity (%) Accuracy (%) MIA ELISA† DGP IgA 0.89 71.6* 75.0* 92.7 95.2 83.9* 86.8* DGP IgG 0.86 66.3 65.2 96.8 98.4 83.8 84.3 TTG IgA 0.97 81.8* 79.3* 91.5* 90.5* TTG IgG 0.48 13.0 28.3 100.0 63.0 67.6

Combination testing for antibodies in the diagnosis of coeliac disease: comparison of multiplex immunoassay ELISA methods. Aliment Pharmacol 2008; 28: 805-13 Test κ-Statistics Sensitivity (%) Specificity (%) Accuracy (%) MIA ELISA DGP IgA or IgG 0.87 77.8 78.3 90.2 94.4 85.0 87.5 TTG IgA or IgG 0.93 82.2 80.4 98.4 96.0 91.5 89.4 DGP IgA or TTG IgA 83.0 92.7 95.2 86.6 90.1 DGP IgG or TTG IgA 0.96 84.4 82.6 95.9 97.6 91.1 91.2 DGP IgA or IgG or TTG IgA 0.91 85.6 83.7 88.3 89.8 DGP IgA or IgG or TTG IgA or IgG 0.88 91.9 88.4

Combination testing for antibodies in the diagnosis of coeliac disease: comparison of multiplex immunoassay ELISA methods. Aliment Pharmacol 2008; 28: 805-13 Test Sensitivity (%) Specificity (%) Accuracy (%) MIA ELISA DGP IgA and IgG 0.90 60.0 61.4 99.2 82.7 83.5 TTG IgA and IgG 0.50 11.1 25.3 100.0 62.6 68.7 DGP IgA and TTG IgA 0.96 70.5 71.3 98.4 86.7 87.2 DGP IgG and TTG IgA 0.88 63.3 60.9 84.1 83.4 DGP IgA and IgG and TTG IgA 0.91 58.6 82.5 DGP IgA and IgG and TTG IgA and IgG 0.57 20.7 66.8

Volta et al. Deamidated gliadin peptide antibodies as a routine test for celiac disease: a prospective analysis J Clin Gastroenterol 2009

test SENSIBILITA’ SPECIFICITA’ IgA tTG 93,7% 96,6% IgA EMA 91,6% 100% Volta et al. Deamidated gliadin peptide antibodies as a routine test for celiac disease: a prospective analysis J Clin Gastroenterol 2009 test SENSIBILITA’ SPECIFICITA’ IgA tTG 93,7% 96,6% IgA EMA 91,6% 100% IgA DGP 84,3% 79,8% IgG DGP 82,3% 98,9%

Individual values of AGA IgA II, AGA IgG II, and tTG IgA measured in the sera of children with (CD) or without (CS) typical celiac disease duodenal histology Basso, D. et al. Clin Chem 2009;55:150-157 Copyright ©2009 American Association for Clinical Chemistry

Basso, D. et al. Clin Chem 2009;55:150-157 Positive result Sensitivity Specificity PPV NPV AGA IgA II and tTG IgA 80.7 100 80.4 AGA IgA II or tTG IgA 92.5 90.6 AGA IgG II and tTG IgA 77.6 99.2 77.8 AGA IgG II or tTG IgA 95.0 95.3 96.2 93.8 AGA IgA II and AGA IgG II and tTG IgA 72.0 73.8 AGA IgA II or AGA IgG II or tTG IgA 89.8 92.2 93.4

ROC curves of AGA IgA II, AGA IgG II, and tTG IgA in distinguishing celiac disease from control children without total IgA deficiency Basso, D. et al. Clin Chem 2009;55:150-157 Copyright ©2009 American Association for Clinical Chemistry

Median values, interquartile range, and outliers of AGA IgA II, AGA IgG II, and tTG IgA of children with CD subdivided according to Marsh-Oberhuber classification Basso, D. et al. Clin Chem 2009;55:150-157 Copyright ©2009 American Association for Clinical Chemistry

Sensitivity (%) of antibody tests at more than 99% specificity* Antibodies Against Deamidated Gliadin as New and Accurate Biomarkers of Childhood Coeliac Disease JPGN 2009: 49;52-58 23

Antibodies Against Deamidated Gliadin as New and Accurate Biomarkers of Childhood Coeliac Disease JPGN 2009: 49;52-58 24

Serum and intestinal celiac disease-associated antibodies in children with celiac disease < 2 years of age JPGN 2010; 50:43-48 25

(Amarri & Volta) Pazienti celiaci sesso: 4 F, 3M età: range 16 – 28 mesi sintomi all’esordio: diarrea, addome globoso, ipotonia muscolare, calo ponderale, astenia, famigliarità (1) *AGA IgA vn <10, borderline 8-15, positivo > 15

Controlli sesso: 3 F e 3 M età: range 12 - 28 mesi patologie: neurologiche, polmonari, F-U soggetti asintomatici per infezioni peri-natali Tutti i marker di celiachia e altri auto-anticorpi negativi, solo un caso di AGA IgA borderline (6.8) AGA IgA vn <10, borderline 8-15, positivo > 15

Adattato da Basso, D. et al. Clin Chem 2009;55:150-157 Sensitivity Specificity PPV NPV ≤ 2 anni AGA IgA II 80.0 93.8 96.0 71.4 AGA IgG II 96.7 100 94.1 tTG IgA 90 84.2

Change in DGP antibodies and TGAA in children receiving GFD vs regular diet Liu, Edwin et al JPGN 2007 30

Liu, Edwin et al JPGN 2007 Top, In children treated with GFD, DGP antibody levels significantly decreased (most resolved); however, children receiving a regular diet had persistently high levels of DGP antibodies. Bottom, TGAA levels also decreased significantly with GFD treatment, compared with children receiving a regular diet; however, the majority of children treated with GFD remained TGAA positive. 31

Liu, Edwin et al JPGN 2007 Representative graphs of children treated with GFD over time. Arrow indicates time of biopsy with confirmed celiac disease, and institution of GFD. Sometimes, rarely, and never indicate patient-reported frequency of dietary indiscretion. A, Example of persistently positive TGAA with resolution of DGP antibodies. B, Example of transiently positive TGAA while DGP remained negative at all time points. C, Example of persistently positive TGAA and DGP antibodies. D, Example of complete resolution of both TGAA and DGP antibodies. Solid line = DGP antibody, dashed line = TGAA 32

Gliadina Deamidata (DGP) L’anticorpo di classe IgG (IgG DGP) è la vera novità In aggiunta alle tTG aumenta la nostra capacità diagnostica IgG DGP: Può essere impiegato nei deficit di IgA Può essere impiegato sotto i due anni di età Permette una conferma diagnostica e aumenta la specificità dei due test combinati IgG DGP è un marcatore più tempestivo della aderenza alla dieta aglutinata

Possibile variazione iter diagnostico sierologico IgA tTG IgA tTG IgA EMA IgA AGA IgG DGP IgG tTG Adattato da Volta et al. Expert Rev Gastroenterol Hepatol 2010