Sickle cell anemia (SCA) is a disorder characterized by a heterogeneous clinical outcome. In the present study, we investigated the associations between Tumor Necrosis Factor-alpha (TNF-alpha) -308G>A and Interleukin 8 (IL-8) -251A>T gene polymorphisms, medical history and classical biomarkers in children with steady-state SCA. In total, 210 SCA patients aged 2-21 years and 200 healthy controls were studied. Gene polymorphisms, betaS-globin haplotypes and a 3.7-kb deletion in alpha2-thalassemia (α2-thal3.7 kb) were investigated by PCR/RFLP analysis, and cytokine levels were determined by ELISA. Splenomegaly (p=.032) was more prevalent among children younger than 5 years of age. The A allele of the TNF-alpha -308G>A gene polymorphism and the presence of α2-thal3.7 kb were associated with an increase risk of splenic sequestration events (p=.001; p=.046), while the T allele of the IL-8 -251A>T gene polymorphism was considered to be a protective factor for splenomegaly events (p=.032). Moreover, the A allele of the TNF-alpha -308G>A gene polymorphism was associated with high TNF-alpha levels (p=.021), and the hemoglobin F and hemoglobin S haplotypes were correlated with serum levels of IL-8. The logistic regression analysis showed significant effects of the TNF-alpha and IL-8 gene polymorphisms, beta(S)-globin gene haplotypes and α2-thal3.7 kb on the occurrence of splenic sequestration events. Our study emphasizes that the identification of new genetic and immunological biomarkers and their associations with classical markers is an important strategy to elucidate the underlying causes of different SCA phenotypes and their effects on patient outcome.

Introduction The vascular alterations play an important role in the SCA chronic inflammatory state with the participation of different cell types, including macrophages and dendritic cells (DCs). Aim Here, we evaluated the mRNA expression of TLRs in DCs cells pre and post LPS stimulus and also measured IL-1β, TNF-α and IL-10 cytokines in plasma and supernatant of DCs pre and post LPS challenge, in order to indentify a possible role of this cell and receptor in the inflammatory state described in sickle cell anemia. Methods In vitro generation of immature DCs (imDC) monocyte-derived was obtained of monocytes from peripheral blood mononuclear cells (PBMC) of seven hospitalized HbSS patients. Relative mRNA abundance of each transcript was investigated by quantitative real time PCR and cytokines levels were measured by ELISA. Results We found that different HbSS patients showed specific DCs TLR expression and a differential levels of IL-1β among HbSS patients with and without pneumonia history (p=0.0253) and with hemoglobin concentration (p=0.0288) (Fig. 1). There was difference of TLR4 mRNA expression between HbSS patients groups without and with leg ulcers history (0.320+0.302 and 1.60+0.014) respectively (p=0.0016); with platelets count between HbSS patients groups with TLR2 expression < 50th (569.7+3.512) and > 50th (304.5+111.7) (p=0.0102) and reticulocytes count between HbSS patients groups with TLR2 expression < 50th (15.97+2.450) and > 50th (2.025+2.417) (p=0.0007) and of TNF-alpha concentration in DCs supernatant culture among HbSS patients with TLR5 expression < 50th (30.57+11.92) and > 50th (7.053+6.918) (p=0.0496) and of IL-10 concentration in DCs supernatant culture among HbSS patients with TLR5 expression < 50th (3.525+0.921) and > 50th (5.790+1.226) (p=0.0374) (Fig.2). It was also found statistic difference of IL-1 beta concentration in DCs supernatant culture post LPS stimulus between HbSS patients without and with pneumonia history (P=0.0253); analysis of TLR4 mRNA expression between HbSS patients without and with leg ulcer history (P=0.0016); analysis of hemoglobin concentration between HbSS patients with different plasma IL-1 beta concentration (P=0.0288) Conclusion Ours results show that these molecules and cell type possibly have an important role in maintain the inflammatory state described in this disease. Disclosures: No relevant conflicts of interest to declare.