Autoimmune Markers in Children with Chronic Immune Thrombocytopenia

Introduction: Chronic immune thrombocytopenia (ITP) is defined as isolated thrombocytopenia lasting longer than 12 months. Rheumatologic diseases, immunodeficiencies and thyroid diseases may coexist with chronic ITP due to possible immune dysregulation.

Aim: To evaluate the accompanying autoimmune diseases in children with chronic ITP.

Materials-Methods: A total of 154 children with chronic ITP (F /M: 1) diagnosed between 1995 and 2018 were included. Patients were evaluated with immunoglobulin levels, ANA, anti dsDNA, C3, C4, anti TPO, anti TG, T4, TSH, tissue transglutaminase IgA and Ig G.

Results: Of the 154 patients, 79 were female (51.3%) and 75 were male (48.7%). Mean age of the patients was 13.6 ± 5.8 years, mean age of diagnosis was 7 years ± 4. None of the patients had severe infections requiring hospitalisation. None of the patients had symptoms or findings of an autoimmune disorder. Of 154, two had low IgA levels (<7 mg / dL) and they were diagnosed as IgA deficiency. IgM and IgG levels were normal in all. C3 level was low in four patients (3%) and C4 level was low in one patient (0.7%). ANA was positive in 16 (12%) of the patients and anti-dsDNA was positive in four patients (0,3%). In three patients, Anti-dsDNA positivity was accompanied with ANA positivity and in one patient, C3 was low. These patients were followed up by pediatric rheumatology clinic. Twenty two patients had elevated anti TPO (15.5%) and 18 patients had elevated anti TG (12.7%) levels. Majority of patients with high thyroid autoantibodies were female (67.5%). Out of 129 patients evaluated by thyroid tests including fT4, TSH, AntiTPO and AntiTG, 29 (% 22,4) were diagnosed as Hashimoto thyroiditis. Thyroid hormone replacement was started in one patient . Of 93 patients evaluated with anti-tissue transglutaminases, 7 were found to have at least one positive TTG IgA or IgG. Two of these patients underwent endoscopy, but no evidence of celiac disease was found. In total, the number of patients with at least onepositive autoimmune marker was 54 (35%).

Discussion and Conclusion: Chronic ITP is known to accompany autoimmune diseases. Autoimmune diseases in patients with ITP may occur at any time in 10 years of diagnosis. Further studies for the detection of subclinical autoimmune conditions should be performed with a profit- loss account. Antibodies may be positive even when there is no clinical findings of the diseases. Further follow-up is needed to understand the clinical significance of autoimmune markers in chronic ITP.