Autoimmune diseases affect up to 10% of the world's population and, as a whole, they are far more common in females, although differences exist according to the single disease and also in different age groups. In childhood-onset autoimmune diseases, the sex bias is generally less evident than in adults, probably for the different hormonal milieau, being estrogens strongly implicated in the development of autoimmunity. Still, some rheumatic conditions, such as juvenile idiopathic arthritis (JIA), show a strong predilection for girls (F:M = 3-6.6:1), and differences may coexist between males and females regarding disease outcome. For example, chronic anterior uveitis associated with JIA affects more commonly girls but boys tend to have a more severe course. Systemic lupus erythematosus predominantly affects girls and women (F:M = 3-5:1 in children, F:M = 10-15:1 in adults). Behςet's disease has been reported to be more prevalent in adult males (F:M = 1:1-4); in children, there are no differences. The sex ratio is equal in children and adults for Henoch-Schönlein purpura (F:M = 1:1). A higher male-to-female ratio exists for Kawasaki disease (F:M = 1:1.1-1.6 in children, F:M = 1:1,5 in adults). Juvenile dermatomyositis (F:M = 2-5:1), systemic sclerosis (F:M = 4:1 in children, F:M = 6:1 in adults), and Takayasu arteritis (F:M = 2:1 in children, F:M = 7-9:1 in adults) are more common in girls and women then in boys and men. There is no gender bias for acute rheumatic fever in children, while in adults, the F:M ratio is 2:1. Given that estrogen levels are not different between genders during childhood, pediatric rheumatic diseases could represent good models to study other mechanisms related to the development of autoimmunity. Recently, the levels of miRNA expression, and their variation according to sex chromosomes, have been linked to the development of autoimmune diseases, with different impact among sexes. This review will focus not only on the sex bias reported in the more common rheumatic conditions of childhood, focusing on differences in incidence, but also on outcome and trying to depict the mechanisms underlying those differences.

The natural history of the immune thrombocytopenia (ITP) is interesting and intriguing because it traces different steps underlying autoimmune diseases. The review points out the main steps that have accompanied the stages of its history and the consequential changes related to its terminology. ITP is an autoimmune disease resulting from platelet antibody-mediated destruction and impaired megakaryocyte and platelet production. However, research advances highlight that a complex dysregulation of the immune system is involved in the pathogenesis of this condition. The review examines the role of the multiple immune components involved in the autoimmunity process, focusing on the more recent mechanisms, which could be new promising therapeutic targets for ITP patients.

Kawasaki disease (KD) is one of the most common vasculitides of childhood and the main cause of acquired heart disease in developed countries. Intravenous immunoglobulin (IVIG) in association with aspirin represents the main treatment for KD. However, 10-20% of patients fail to respond to standard treatment and have an increased risk of cardiac complications. There is currently no accepted protocol for treatment of resistant cases. Several authors highlighted the role of interleukin-1 (IL-1) as a mediator of inflammation in KD and suggested the possibility of using IL-1 or its receptor as a target of therapy. The use of IL-1 inhibitors in patients with KD has been reported in the scientific literature, but data are largely limited to individual case reports and small case series. We summarized the scientific literature related to the use of anakinra, analyzing preclinical and clinical data. Thirty-eight patients have been described so far, most of them with KD-related complications. Twenty-two were described in case reports and case series, while 16 were patients from the completed KAWAKINRA phase IIa study. Almost all patients received clinical benefit, and no relevant side effects were noted. Based on this evidence, in our opinion, anakinra may be considered as an option after the failure of the first IVIG infusion, especially in patients with coronary involvement.

BackgroundChronic recurrent multifocal osteomyelitis (CRMO) is a rare condition that commonly affects the clavicle and pelvis.Case presentationWe report here a case a 12 years old girl with CRMO arising with recurrent episodes of left supraorbital headache, followed by the appearance of a periorbital dyschromia. Magnetic resonance imaging (MRI) of the skull and orbits revealed an important subacute inflammatory process. Few months after, the child presented a painful swelling of the left clavicle; the histological examination of the related biopsy allowed to establish the diagnosis of CRMO.ConclusionCRMO presenting as acute headache involving neurocranium is rare; to our knowledge this is the first recognized case in the world literature.This pathological condition is frequently misdiagnosed as infection or neoplasm and needs a deep investigation for the differential diagnosis. The physical, laboratoristic and instrumental diagnostic investigations of the patient and the treatment employed are described in detail.