CTLA4 and hematocrit: Evidence provided by our studies of Slovenian HT patients indicated a strong association between TAb production and the three CTLA-4 SNPs, including -318C/T in the promoter, 49A/G and CT60. In patients carrying one of those three SNPs, evidently higher TPOAb concentrations were demonstrated in relation to the polymorphous CTLA-4 gene, while the association with the TgAb concentrations was weaker [49, 50].