This study was undertaken to establish reference values of exhaled nitric oxide fraction (FeNO) and its determinants in healthy Asian children.693 healthy Asian children aged 5-18 yrs were assessed using a single-breath online FeNO measurement (exhaled flow 50 mL?s -1 ), questionnaires, anthropometric measurements, spirometry and total and specific immunoglobulin (Ig) E.Geometric mean FeNO and the upper 95% CI were 13.7 ppb and 49.7 ppb, respectively, for healthy children, and 11.2 ppb and 30.2 ppb, respectively, for those without allergic sensitisation. FeNO was positively associated with age, allergic sensitisation, total IgE, ambient nitric oxide, measurement in the afternoon, and drinking water within 1 h before testing, and was negatively associated with weight. In healthy children without allergic sensitisation, age was the single best explanatory variable. The FeNO predicted values were 1-2 ppb higher in Asian than in Caucasian children in earlier studies, while the upper 95% CI were 9-10 ppb higher.In conclusion, the upper limits of normal FeNO in Asian children depend on age, from 21 ppb in young children to 39 ppb in adolescents. Ethnicity, age, allergic sensitisation, total IgE, ambient nitric oxide, time of testing, drinking water and weight are important determinants.

FeNO measurement discriminates children with and without allergic sensitization independent of allergic symptoms. On the other hand, low FeNO levels in children may help exclude allergic asthma but high levels may be caused by allergic sensitization, older age, rhinitis, and lower BMI, in addition to asthma.

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We present a case of a 21-year-old male diagnosed with difficult to treat idiopathic thrombocytopenia and autoimmune haemolytic anaemia at the age of 14. He initially improved with high doses of oral prednisone however relapsed at the age of 16, requiring multiple immunosuppressive agents, intravenous immunoglobulins (IVIG), splenectomy and Eltrombopag to induce remission. He was noted to have hypogammaglobulinemia and low memory B cells, however ongoing IVIG therapy precluded vaccine studies and functional antibody deficit could not be demonstrated.Five years later he presented to hospital with bilateral sixth nerve palsies, raised intracranial pressure and new, widespread lymphadenopathy. An inguinal lymph node biopsy revealed non-caseating granulomas. Although there was an initial resolution of ocular symptoms with high doses of prednisone, our patient re-presented 3 weeks later with bilateral lower limb weakness and several falls. MRI spine imaging revealed symmetrical granulomatous inflammation in the nerve roots of the cauda equina. Reexamination of the inguinal lymph node with further immunochemistry analysis revealed intact lymphoid tissue architecture and presence of plasma cells.Sarcoidosis is an idiopathic, multi-system disorder that is characterised by non-caseating granulomas that are histologically indistinguishable from the lesions present in the granulomatous variant of common variable immunodeficiency. As the clinical features of the two disorders can also significantly overlap, the presence of plasma cells and normal architecture in the lymph node can be helpful in making the diagnosis. We discuss a rare case of neurosarcoidosis involving the peripheral nervous system and further outline diagnostic and management dilemmas. Background: Ataxia-telangiectasia (AT) is an autosomal recessive neurodegenerative disorder associated with immune deficiency and cancer susceptibility caused by a defect in the ataxia-telangiectasia mutated (ATM) gene resulting in impaired DNA repair. Lymphoma and leukaemia is the most commonly associated malignancy with childhood AT.