The chronic inflammatory state in
sickle cell anemia (SCA) is associated with several factors such as the following: endothelial damage; increased production of
reactive oxygen species;
hemolysis; increased expression of adhesion molecules by leukocytes, erythrocytes, and platelets; and increased production of proinflammatory
cytokines. Genetic characteristics affecting the clinical severity of SCA include variations in the
hemoglobin F (HbF) level, coexistence of
alpha-thalassemia, and the haplotype associated with the HbS gene. The different haplotypes of SCA are Bantu, Benin, Senegal, Cameroon, and Arab-Indian. These haplotypes are associated with ethnic groups and also based on the geographical origin. Studies have shown that the Bantu haplotype is associated with higher incidence of clinical complications than the other haplotypes and is therefore considered to have the worst prognosis. This study aimed to evaluate the profile of the proinflammatory
cytokines interleukin-6,
tumor necrosis factor-α, and
interleukin-17 in patients with SCA and also to assess the haplotypes associated with
beta globin cluster S (HBB(*)S). We analyzed a total of 62 patients who had SCA and had been treated with
hydroxyurea; they had received a dose ranging between 15 and 25 (20.0±0.6)mg/kg/day for 6-60 (18±3.4)months; their data were compared with those for 30 normal individuals. The presence of HbS was detected and the haplotypes of the beta S gene cluster were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Our study demonstrated that SCA patients have increased inflammatory profile when compared to the healthy individuals. Further, analysis of the association between the haplotypes and inflammatory profile showed that the levels of
IL-6 and TNF-α were greater in subjects with the Bantu/Bantu haplotype than in subjects with the Benin/Benin haplotype. The Bantu/Benin haplotype individuals had lower levels of
cytokines than those with the Bantu/Bantu haplotype and greater levels than those of subjects with the Benin/Benin haplotype. For
IL-17, a slight trend toward decreased levels was observed in the subjects with the Benin/Benin haplotype, when compared to those with the Bantu/Bantu and Bantu/Benin haplotypes; however, this difference was not statistically significant. Our results show that genetic polymorphisms in
sickle cell anemia are associated with the inflammatory profile.