ABSTRACT
Twin hematopoietic chimera in humans is a phenomenon that was discovered accidentally and the prevalence of which remains unclear. The resolution of chimera cases requires studying family medical records, data analysis, and investigations of hematopoietic cells and cells from other tissues. The interactions among ABO, Lewis, and secretor histo-blood group systems are explored to resolve cases of hematopoietic chimera. Here we report a rare case of hematopoietic chimera where twins present a mixed field reaction in the ABO, Rh, and Kidd red blood cell phenotyping. Using red blood cells separated from the mixed field as well as molecular approaches and investigations of family members, we identify inconsistent genotypes with the Mendelian inheritance pattern when comparing the peripheral blood with the buccal epithelium of the male twin and his twin sister. Analysis of the ABO, Lewis, and secretor phenotypes, and genomic DNA from buccal epithelium showed the genotypes ABO*A1.01/ABO*B.01 and FUT2*01N.02/ FUT2*01N.02 in the male twin and the genotypes ABO*O.01.01/ABO*O.01.02 and FUT2*01/FUT2*01 in the female twin. The results of the HLA-DRB1 genotyping showed inconsistency between the male and his twin sister. We conclude that the serological analyses combined with molecular approaches used in this study are good tools to resolve cases of hematopoietic chimera.
ABSTRACT
CC chemokine receptor type 5 (CCR5) is a chemokine receptor that influences the immune response to infectious and parasitic diseases. This study aimed to determine whether the CCR5Δ32 and CCR5 59029 A/G polymorphisms are associated with the development of ocular toxoplasmosis in humans. Patients with positive serology for Toxoplasma gondii were analyzed and grouped as 'with ocular toxoplasmosis' (G1: n=160) or 'without ocular toxoplasmosis' (G2: n=160). A control group (G3) consisted of 160 individuals with negative serology. The characterization of the CCR5Δ32 and CCR5 59029 A/G polymorphisms was by PCR and by PCR-RFLP, respectively. The difference between the groups with respect to the mean age (G1: mean age: 47.3, SD±19.3, median: 46 [range: 18-95]; G2: mean age: 61.3, SD±13.7, median: 61 [range: 21-87]; G3: mean age: 38.8, SD±17.9, median: 34 [range: 18-80]) was statistically significant (G1 vs.G2: p-value <0.0001; t=7.21; DF=318; G1 vs.G3: p-value <0.0001; t=4.32; DF=318; G2 vs. G3: p-value <0.0001; t=9.62; DF=318). The Nagelkerke r2 value was 0.040. There were statistically significant differences for the CCR5/CCR5 (p-value=0.008; OR=0.261), AA (p-value=0.007; OR=2.974) and AG genotypes (p-value=0.018; OR=2.447) between G1 and G2. Individuals with the CCR5/CCR5 genotype and simultaneously the CCR5-59029 AA or AG genotypes have a greater risk of developing ocular toxoplasmosis (4% greater), which may be associated with a strong and persistent inflammatory response in ocular tissue.
