Introduction Etiological diagnosis of fever in sickle cell disease (SCD) children is often challenging. Objective: to analyze the pattern of inflammatory biomarkers in SCD febrile children and controls, in order to determine predictors of severe bacterial infection (SBI). Methods Prospective, case-control study of febrile and steady-state SCD children carried out during 3 years. Clinical characteristics and laboratory parameters, including 10 serum proinflammatory cytokines (IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-17a, IFN-γ and TNF-α) and comparisons among study subgroups were analyzed. Results A total of 137 patients (78 cases and 59 controls) were included in the study; 78.5% males, median age 4.1 (1.7-7.5) years. Four cases were diagnosed with SBI, 41 viral infection (VI) and 33 no proven infection (NPI). IL-6 was significantly higher in patients with SBI than in patients with VI or NPI (163 vs 0.7 vs 0.7 pg/ml, p < 0.001), and undetectable in all controls. The rest of the cytokines analyzed did not show any significant difference. The optimal cut-off value of IL-6 for the diagnosis of SBI was 125 pg/mL, with high PPV and NPV (PPV of 100% for a prevalence of 5, 10 and 15% and NPV of 98.7%, 97.3% and 95.8% for those prevalences, respectively). Conclusion We found that IL-6 (optimal cut-off value of 125 pg/ml) was a very good marker for SBI in this cohort of febrile SCD children, with high PPV and NPV. Therefore, IL-6 may be useful, alone or combined with other biomarkers, to guide the management of these patients.

Objetives. To perform a description of the etiology of hospitalized children with community-acquired pneumonia (CAP) in Spain and analyze predictors related to etiology. Hypothesis. The different etiological groups of pediatric CAP are associated to different clinical, radiographic and analytical data. Design. Observational, multi-center, prospective study. Patient selection. Patients from 1 month to 17 years admitted because of CAP from April 2012 to May 2019. Methods. An extensive microbiological workup was done. Clinical, radiographic and analytical parameters were analyzed in order to differentiate viral, atypical bacteria (AB) and typical bacteria (TyB) pneumonia. Results. 495 children were enrolled. At least one likely causative pathogen was identified in 262 (52.9%). Pathogenic viruses in 155/262 (59.2%), AB in 84/262 (32.1%) and TyB in 40/262 (15.3%). Consolidation was found in 89/138 (64.5%) CAP attributed to virus only, in 74/84 (88.1%) of CAP attributed to AB and 40/40 (100%) of CAP attributed to TyB. Para-pneumonic pleural effusion (PPE) was found in 112/495 (22.6%) patients, 61/112 (54.5%) with a likely causative pathogen: virus 12/61 (19.7%), AB 23/61 (37.7%) and TyB 26/61 (42.6%). Viral etiology was significantly more frequent in younger patients and those with lower oxygen saturation, wheezing, no-consolidation and higher lymphocyte counts. Patients with AB were significantly more likely to have more days of fever at admission and a higher rate of use of antibiotics before admission. Conclusions. Viruses and AB are the main cause of pediatric CAP in Spain. Wheezing, younger age and no-consolidation on the X-ray support viral etiology. Viruses and AB can also cause PPE. The use of antibiotic in pediatric CAP can be restricted.