CD207+CD1a+ cells circulate in pediatric patients with active Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is a rare disease with an unknown etiology characterized by heterogeneous lesions containing CD207+CD1a+ cells that can arise in almost any tissue and cause significant morbidity and mortality. Precursors of pathological Langerhans cells have yet to be defined. Our aim was to identify circulating CD207+CD1a+ cells and their inducers in LCH. Expression of CD207 and CD1a in the blood myeloid compartment as well as thymic stromal lymphopoietin (TSLP) and transforming growth factor ß (TGF-ß) plasma levels were measured in 22 pediatric patients with active disease (AD) or nonactive disease (NAD). In patients with AD vs those with NAD, the myeloid compartment showed an increased CD11b (CD11bhigh plus CD11b+) fraction (39.7 ± 3.6 vs 18.6 ± 1.9), a higher percentage of circulating CD11bhighCD11c+CD207+ cells (44.5 ± 11.3 vs 3.2 ± 0.5), and the presence of CD11chighCD207+CD1a+ cells (25.0 ± 9.1 vs 2.3 ± 0.5). Blood CD207+CD1a+ cells were not observed in adult controls or umbilical cord. Increased TSLP and TGF-ß levels were detected in patients with AD. Interestingly, plasma from patients with AD induces CD207 expression on CD14+ monocytes. We conclude that CD207+CD1a+ cells are circulating in patients with active LCH, and TSLP and TGF-ß are potential drivers of Langerhans-like cells in vivo.

Predictor Variables of Developing Anterior Pituitary Deficiencies in a Group of Paediatric Patients with Central Diabetes Insipidus and Langerhans Cell Histiocytosis.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare histiocytic disorder of unknown etiopathogenesis. Central diabetes insipidus (CDI) is the most frequent endocrine manifestation and is a known risk factor for the development of further anterior pituitary hormone deficiencies (APD). However, not all CDI patients develop APD, as observed during prolonged periods of follow-up. AIM: To find predictors of developing APD in LCH children with CDI followed in our institution. METHODS: We retrospectively analysed 44 patients over a median period (quartiles) of 12.3 years (8.79-14.24). Patients were subdivided into group 1 and group 2, according to absence or presence of APD, respectively. The main variables studied were: (1) chronological age (CA) at LCH diagnosis, (2) the primary site of LCH at diagnosis: low risk (LR) and multisystemic risk organs, and (3) the presence of reactivation. RESULTS: Multivariate Cox regression analysis showed that APD was positively associated with CA at LCH diagnosis [relative risk (RR) 1.14, p < 0.01], the LR clinical form (RR 8.6, p < 0.03), and negatively associated with the presence of reactivations (RR 0.3, p < 0.01). CONCLUSIONS: Patients with older CA at LCH diagnosis, LR clinical forms, and fewer reactivation episodes might represent a subgroup of paediatric LCH CDI patients with a higher risk of developing APD.

Serum levels of interleukin-1 receptor antagonist and tumor necrosis factor-alpha are elevated in children with Langerhans cell histiocytosis.

PURPOSE: Langerhans cell histiocytosis (LCH) is a rare disease with variable prognosis in which lesions and clinical features suggest that pro- and anti-inflammatory cytokines may be involved in its pathogenesis. The authors wished to evaluate whether serum levels of interleukin-1 receptor agonist (IL-1Ra) and tumor necrosis factor-alpha (TNF-alpha) are elevated in children with LCH and decrease after chemotherapy. PATIENTS AND METHODS: Circulating levels of IL-1Ra and TNF-alpha were measured in 23 and 8 children with LCH, respectively, and 7 pediatric controls using commercially available ELISA kits. All patients fulfilled the Histiocyte Society LCH Protocols criteria for diagnosis, stratification, and treatment. RESULTS: Pretreatment concentrations of IL-1Ra and TNF-alpha were found to be significantly elevated in patients with LCH compared with controls. Among LCH substages, a significant difference in IL-1Ra values was observed between individuals with single-system single-site disease vs. multisystem disease with risk-organ dysfunction. In all eight patients evaluated, IL-1Ra levels decreased after 6 weeks of chemotherapy. Lower values of TNF were observed in three patients after treatment. A positive and significant correlation between IL-1Ra and TNF serum concentrations was found. CONCLUSIONS: Patients with LCH have elevated levels of IL-1Ra and TNF, which decrease after chemotherapy.

Prognostic value of soluble interleukin 2 receptor levels in Langerhans cell histiocytosis.

We investigated the prognostic significance of soluble interleukin 2 receptor (sIL-2r) levels in the pre- and post-treatment serum of paediatric patients with Langerhans cell histiocytosis (LCH). Serum levels of sIL-2r from 32 LCH patients and 14 healthy controls were determined using enzyme-linked immunosorbent assay. The LCH patients were classified, evaluated and treated according to the Histiocyte Society's protocols. The following clinical stages were considered: single-system disease (A) divided into single-site (A1; n=4), multiple-site (A2; n=9), and multisystem disease (B) without organ dysfunction (B1; n=5) and with organ dysfunction (B2; n=14). Pretreatment concentrations of sIL-2r were markedly increased at diagnosis in LCH patients compared with controls [in pg/ml, median (range) 9200 (1124-40000) versus 610 (343-800)], P < 0.0001. Levels differed significantly between stages A [3250 (1124-11000)] and B [22750 (3400-40000)], P < 0.05, and between substages A2 and B2, P < 0.05. There was a significant correlation between clinical stages and sIL-2r serum levels, r=0.7996 (P < 0.0001). Patients with > or = 17500 pg/ml of sIL-2r had a 30-month survival of 0.417 (SEM: 0.142) compared with those with levels < 17500 pg/ml, who presented a 30-month survival of 0.848 (SEM: 0.100) (log-rank, P < 0.0001). In multivariate analysis, sIL-2r levels > or = 17500 pg/ml were found to have greater predictive strength than other well-known prognostic factors.

Successful in vivo immunolocalization of Langerhans cell histiocytosis with use of a monoclonal antibody, NA1/34.

The antibody NA1/34 is a murine monoclonal antibody directed against the CD1a surface antigen expressed on normal Langerhans cells, cortical thymocytes, and on lesional cells in Langerhans cell histiocytosis (LCH). Our hypothesis was that NA1/34 would localize sites of disease activity in patients with multisystem LCH. To test this hypothesis, indium 111-labeled NA1/34 was administered to five patients with multisystem LCH and serial gamma scans were obtained for up to 120 hours. Serial serum samples were obtained from one patient for analysis of anti-mouse Ig antibody and NA1/34 levels. Direct and indirect immunofluorescence staining for CD1a and NA1/34 were performed on a tissue biopsy specimen from one patient after administration of the antibody. The 1- and 4-hour scans showed distribution of antibody in the blood pool, but in later scans localization of the antibody was noted in areas of known disease activity in all five patients. Bony lesions, previously seen on skeletal radiographs, were especially well identified. Serum kinetics studies showed clearance of the antibody from the blood pool within 12 hours of administration. Direct binding of NA1/34 to lesional cells was demonstrated by direct immunofluorescence. The only adverse effect was urticaria in one patient. We conclude that NA1/34 localizes disease activity in vivo in bones of patients with LCH with minimal toxic effects. An evaluation of its role in determining disease extent ("staging") and in treatment is now needed.