Summary. The true incidence and prognosis of autoimmune thrombocytopenic purpura (ITP) in adults is unknown. We present the results of a prospective study in a population-based cohort of newly presenting adults ( ‡ 16 years) with ITP and platelet count of < 50 · 10 9 /l, which took place between 1 January 1993 and 31 December 1999 in the former Northern Health Region in the UK (population 3AE08 million). A total of 245 cases were confirmed by bone marrow examination with a median follow-up of 60 months (range 6-78 months). There were 134 females/111 males (1AE2:1). Overall incidence was 1AE6 per 10 5 per annum. Absolute incidence was similar for both sexes, with highest age-specific incidence in those aged > 60 years. Thirty patients (12%) presented with frank bleeding, and 28% were asymptomatic. Forty-five patients (18%) received no treatment, and 135 (55%) received firstline treatment only. Thirty patients (12%) underwent splenectomy. There were four deaths (1AE6%) from bleeding and/or the complications of therapy in this cohort, but only one was in the acute phase of the illness. The majority of patients (155 out of 245) achieved remission (platelet count > 100 · 10 9 /l), with a further 59 (24%) in partial remission with no symptoms (platelet count 30-100 · 10 9 /l). This population-based study suggests that the traditional view of adult ITP as being a predominantly chronic disease that preferentially affects females needs to be modified.

UK National Institute for Health Research.

Rationale: Idiopathic pulmonary fibrosis (IPF) is a devastating progressive disease with limited therapeutic options. Airway macrophages (AMs) are key components of the defense of the airways and are implicated in the pathogenesis of IPF. Alterations in iron metabolism have been described during fibrotic lung disease and in murine models of lung fibrosis. However, the role of transferrin receptor 1 (CD71)-expressing AMs in IPF is not known. Objectives: To assess the role of CD71-expressing AMs in the IPF lung. Methods: We used multiparametric flow cytometry, gene expression analysis, and phagocytosis/transferrin uptake assays to delineate the role of AMs expressing or lacking CD71 in the BAL of patients with IPF and of healthy control subjects. Measurements and Main Results: There was a distinct increase in proportions of AMs lacking CD71 in patients with IPF compared with healthy control subjects. Concentrations of BAL transferrin were enhanced in IPF-BAL, and furthermore, CD71 − AMs had an impaired ability to sequester transferrin. CD71 + and CD71 − AMs were phenotypically, functionally, and transcriptionally distinct, with CD71 − AMs characterized by reduced expression of markers of macrophage maturity, impaired phagocytosis, and enhanced expression of profibrotic genes. Importantly, proportions of AMs lacking CD71 were independently associated with worse survival, underlining the importance of this population in IPF and as a potential therapeutic target. Conclusions: Taken together, these data highlight how CD71 delineates AM subsets that play distinct roles in IPF and furthermore show that CD71 − AMs may be an important pathogenic component of fibrotic lung disease.