Lack of association of the KIR and HLA class I ligands with ZIKV infection in south and southeast of Brazil

BACKGROUND Zika virus (ZIKV) is an emerging arbovirus associated with foetal malformations and neurological complications. The infection is usually associated with mild symptoms. The comparison between the allelic frequency of polymorphic genes in symptomatic infected individuals in the population can clarify the pathogenic mechanisms of ZIKV. During ZIKV infection, cytokines are produced and natural killer (NK) cells are recruited, whose activation depends on signaling pathways activated by specific receptors, such as killer cell immunoglobulin-like receptors (KIR). These molecules interact with human leukocyte antigen (HLA) class I ligands and are encoded by polymorphic genes. OBJECTIVES This study aimed to evaluate the frequency of allelic variants of the genes encoding the KIR receptors and their HLA class I ligands in 139 symptomatic ZIKV-patients and 170 controls negative for the virus, and to evaluate the role of these variants for ZIKV susceptibility. METHODS KIR and HLA class I genes were genotyped using the polymerase chain reaction-sequence specific oligonucleotide (PCR-SSO) technique. FINDINGS No significant differences in the frequency distribution of KIRs and KIR-HLA in patients compared to controls were observed. MAIN CONCLUSIONS KIR and its HLA ligands might play a minor role in ZIKV infection in the south and southeast Brazilian individuals.

Genotyping of Dombrock and Lutheran blood group systems in blood donors from the southwestern region of the state of Paraná, Southern Brazil

Abstract Background Lutheran and Dombrock are two blood group systems with low immunogenic antigens; they can cause mild-to-moderate transfusion reactions. For both, immunophenotyping is not performed in the pretransfusion routine in Brazil. In addition, the distribution of their antigenic frequencies is an important marker of ethnicity. Thus, the goal of this study was to carry out the genotyping of the LU*01, LU*02, DO*01 and DO*02 alleles of the Lutheran and Dombrock blood group systems in blood donors from the southwestern region of the state of Paraná, Southern Brazil. Method Genotyping was performed for 251 blood donors by specific allele-polymerase chain reaction. The genotype and allele frequencies were obtained through direct counting and compared with other Brazilian populations using the chi-square test with Yates correction. Results The distribution of genotype frequencies for LU were 0.4% for LU*01/LU*01, 6.8% for LU*01/LU*02 and 92.8% for LU*02/LU*02 and for DO, they were 19.9% for DO*01/DO*01, 44.6% for DO*01/DO*02 and 35.5% for DO*02/DO*02. The allele and genotype frequencies of LU and DO were similar to those expected for Caucasians, but the DO*01/DO*01 genotype frequency was different to other Brazilian populations. The rare LU*01/LU*01 genotype was found in a loyal blood donor. Conclusion The genotyping techniques allowed the evaluation of the LU*01, LU*02, DO*01 and DO*02 alleles in blood donors registered in the Hemotherapy Center of the southwestern region of Paraná, Southern Brazil, and contributed to a genotyped blood donor database.