Non-celiac Gluten Sensitivity in children with headache: a focus on clinical and immunological aspects.

Headaches are frequent in childhood. The identification of any underlying treatable causes is a primary endpoint. Headache is frequent in patients with gluten-related disorders, particularly Non-celiac Gluten Sensitivity (NCGS). Prevalence of NCGS in children with headache and etio-pathogenetic bases for headache in NCGS are unclear.AIMS OF THE STUDYThe study aimed: 1) to explore the prevalence and the clinical picture of NCGS in children with headache and native anti-gliadin antibodies (AGA); 2) to analyze gene expression profiles in peripheral blood mononuclear cells (PBMCs) from children with headache and NCGS; 3) the measurement of soluble mediators in sera of patients identified by means of gene expression profiling, and to determine serum levels of Tranglutaminase 6 (TG6) antibodies, markers of neurological gluten-related disorders.PATIENTS AND METHODSPatients aged <18 years evaluated for headache at the Child Neuropsychiatry Unit, University Hospital of Verona, Italy, in the period 1/03/13 – 31/07/15 were considered for recruitment. Inclusion criteria: 1) primary headache (ICHD III-beta criteria); 2) to accept determination of total IgA, AGA IgG and IgA, anti-tranglutaminase 2 IgA antibodies (TGA), specific IgE to wheat, gluten, gliadin on serum samples. Exclusion criteria: secondary headache, cranial nerve neuralgia; ongoing treatments introduced or modified less than 2 months before; total or partial IgA deficiency; to have tested positive for TGA or IgE to wheat, gluten, gliadin; enteropathy at duodenal biopsy in AGA-positive patients. According to the diagnostic algorithm for NCGS, AGA-positive patients underwent a 3 months – period on gluten-free diet (GFD) followed by reintroduction of dietary gluten for 3 months (gluten challenge). AGA-negative patients continued on their normal diet. The headache clinical course was evaluated by means of standardized scales and questionnaires.PBMCs were collected from NCGS patients in active phase of the disease for gene expression profiling and consequently soluble CTLA-4 (sCTLA-4) and soluble gp130 (sgp130) were chosen to be determined in sera. Soluble CD25 (sCD25), a biomarker for T lymphocyte activation, and TG6 IgA and IgG were also measured in sera. RESULTSSeventeen patients were recruited with migraine or tension-type headache: 11 subjects (mean age, 10.6 years; age range, 7.9-12.5 years) tested positive for AGA, 6 children (mean age, 11.6 years; age range, 9.1-13.8 years) were AGA-negative. None of AGA-positive subjects had enteropathy. Six out 11 AGA-positive patients (55%) received the diagnosis of NCGS. No headache features resulted to be typical of NCGS patients. Gastrointestinal symptoms occurred more frequently in NCGS patients (50%). Extra-intestinal symptoms could not distinguish NCGS patients among other patients.Three patients out 11 (27%) tested positive for TG6 antibodies; all also tested as AGA-positive. Patients with high levels of TG6 antibodies did not show improvement on GFD for 3 months.The gene expression profiling of PBMCs documented up-regulation genes related to T- and B-lymphocyte activation, Th17 cell subset and type I Interferon signature.Levels of sCTLA-4 were higher in AGA-positive patients and markedly reduced on GFD, despite NCGS was not confirmed in some patients. Serum levels of sgp130 and sCD25 were similar in all groups. CONCLUSIONSA subgroup of children with headache has Non-celiac Gluten Sensitivity. Experimental data in NCGS patients suggest the existence of an activated immune response with a type-1 Interferon signature, which is typical of autoimmune diseases. High levels of serum sCTLA-4 in AGA-positive patients may be a clue for gluten sensitization and involvement of adaptive immunity.TG6 antibodies in sera may predict a poor clinical response to GFD upon 3 months – period.