Investigate a possible association between SNVs of IL6 and IL-6 serum levels with clinical and laboratory data in adults with cardiovascular disease followed at the Hospital Universitário Francisca Mendes (HUFM) in Manaus ‒ Amazonas.

This study, a cross-sectional design, was carried out between March/2018 and October/2020. 159 patients with diagnosis, surgical intervention and treatment to some cardiomyopathies were included. Patients answered a questionnaire and provided blood sample. Hematological and biochemical data was obtained from the medical records. DNA extraction was performed by Brazol method (LGC Biotecnologia, SP Brazil). Analysis of SNVs was performed by real-time PCR (qPCR), TaqMan® system, and analyzed by QuantStudio™6 Flex Real-Time PCR System (Applied Biosystems) platform to the following IL-6 probes: rs2069832, rs2069835, rs2069845, rs2069849, rs1524107, rs1800795; at the Laboratório de Análise Especializada em Biologia Molecular (LAEBM) of the Universidade Federal do Amazonas (UFAM).

High IL-6 levels were observed among the patients. Furthermore, carriers of variant allele of each analyzed probe revealed slightly higher mean level of IL-6. The highest IL-6 serum levels were found in patients diagnosed with Angina Pectoris (25.65±3.2 pg/mL), followed by Aortic Aneurysm (22.48±3.86 pg/mL; p=0.034) and Acute Infarction of the Myocardium (23.03±2.51 pg/mL; p=0.017). The AB blood group presented higher levels of IL-6 (p=0.027) in comparison with other groups. Patients that presented the variant allele “G”(rs2069832) had a higher prevalence ratio for blood transfusion; red blood cell transfusion (RR=4.41; 95% CI 1.65‒11.75; p=0.002); platelet transfusion (RR=4.29; 95% CI 1.74‒10.22; p<0.001); fresh plasma transfusion (RR=4.05; 95% CI 1.67‒9.18; p<0.001) and cryoprecipitate transfusion (RR=4.23; 95% CI 1.69‒10.57; p<0.001).

In the last 5 years, new technologies and GWAS studies have identified several changes related to cardiovascular diseases, with possible involvement of the ABO locus to acute myocardial infarction and possible cardiovascular biomarkers. The use of blood transfusions is a quality indicator in cardiac surgery, although no analyzed variant was associated with hospitalization and/or surgery success. The IL-6 levels were elevated in all studied patients, although slightly higher in those carriers of the mutant genotypes of each analyzed variant. High levels of IL-6 are reported in patients undergoing cardiac surgery and are recognized as an early biomarker of systemic inflammatory response after surgery.

We found that IL-6 levels were elevated in all patients in the study, although higher in carriers of the variant genotype, although, no significant association between genotypes and IL-6 levels was found. The “AB” blood group presented the highest levels of IL-6. The presence of the variant allele “G” (rs2069832) was associated with an increased risk to blood transfusion.