The role of epigenetics in childhood autoimmune diseases with hematological manifestations.

Autoimmune diseases with hematological manifestations are often characterized by chronicity and relapses despite treatment, and the underlying pathogenetic mechanisms remain unknown. Epigenetic alterations play a vital role in the deregulation of immune tolerance and the development of autoimmune diseases. In recent years, study of epigenetic mechanisms in both adult and childhood autoimmune disorders has been seeking to explain the pathophysiology of these heterogeneous diseases and to elucidate the interaction between genetic and environmental factors. Various mechanisms, including DNA methylation, histone modifications (chromatin remodeling), and noncoding RNAs (ncRNAs), have been studied extensively in the context of autoimmune diseases. This paper summarizes the epigenetic patterns in some of the most common childhood autoimmune disorders with hematological manifestations, based on epigenetic studies in children with primary immune thrombocytopenia (ITP), systemic lupus erythematosus (SLE), and juvenile idiopathic arthritis (JIA). Research findings indicate that methylation changes in genes expressed on T cells, modifications at a variety of histone sites, and alterations in the expression of several ncRNAs are involved in the pathogenesis of these diseases. These mechanisms not only determine the development of these diseases but also affect the severity of the clinical presentation and biochemical markers. Further studies will provide new tools for the prevention and diagnosis of childhood autoimmune disorders, and possible novel treatment options.

Prognostic Factors for Immune Thrombocytopenia Outcome in Greek Children: A Retrospective Single-Centered Analysis.

Immune thrombocytopenia (ITP) in children has a varied course and according to duration is distinguished as newly diagnosed (<3 months), persistent (3-12), and chronic (>12) types. Several studies have evaluated the prognostic factors for the progression of the disease, but similar works have yet to be performed in Greece. We aimed to identify prognostic markers for the three forms of the disease in 57 Greek children during a 13-year period. Information regarding age, gender, preceding infection, bleeding type, duration of symptoms and platelets at diagnosis, treatment, disease course, and immunological markers was recorded. 39 children had newly diagnosed, 4 persistent, and 14 chronic disease. Chronic ITP children were more likely to be of age > 10 years (p = 0.015) and have gradual initiation of the disease (p = 0.001), platelets > 10 × 109/L (p = 0.01), and impaired immunological markers (p < 0.003) compared to newly diagnosed/persistent groups. Recent history of infection was found mainly in the newly diagnosed/persistent group (p = 0.013). None of the children exhibited severe spontaneous bleeding. Conclusion. Even though ITP in children usually has a self-limited course, with rare serious bleeding complications, the chronic form of the disease is characterized by different predictive parameters, which can be used in clinical practice.

aHUS associated with C3 gene mutation: a case with numerous relapses and favorable 20-year outcome.

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is frequently associated with gene mutations in complement-regulatory proteins and activators. Different complement C3 gene mutations have been associated with different outcomes in aHUS. CASE-DIAGNOSIS/TREATMENT: We report the case of a 21-year-old male with a C3 heterozygous gene mutation (p.Ile1157Thr) who developed aHUS at the age of 10 months and had six relapses, the last at the age of 14.5 years. Each relapse was characterized by an apparent predominance of hematological manifestations with milder renal involvement and was followed by complete recovery, with creatinine values and hematological parameters usually recovering after the 3rd to 6th day of hospitalization. The patient was treated with plasma infusion, apart from the initial and the last episode, when dialysis was needed. Twenty years after the onset, he retains normal renal function, with no proteinuria or hypertension. One similar case of highly recurrent aHUS carrying the same C3 mutation as our patient with recovery of renal function has been previously reported. CONCLUSIONS: We further support that aHUS associated with the p.Ile1157Thr C3 mutation may be highly recurrent, but with recovered renal function. The prevalent p.Ile1157Thr C3 gene mutation has variable disease manifestations and both severe and milder renal phenotypes have been found.