Transferrin C subtypes in patients with rheumatoid arthritis

Transferrin (Tf) subtypes were investigated in 128 patients with rheumatoid arthritis (RA) and the frequencies of TfC subtypes were compared with the results in normal individuals. The frequencies of the Tf genes: C1, C2, C3, D1, and D2 were 0.4765, 0.3867, 0.0742, 0.0390 and 0.0234, respectively. The frequency of TfC2 gene was significantly higher in these patients (0.3867) compared to the value in the control group (C2 = 0.247). The relative risk of RA in association with TfC1C2 type was 2.0, while it was 0.18 in association with TfC1C1 type and the results were statistically significant. This paper confirms the significant association between TfC2 and RA. Furthermore, it appears from our results that TfC1 homozygous phenotype is protective for the development of RA. The results are discussed in the light of earlier suggestions that the TfC2 subtype confers an increased risk of cellular damage by enhancing hydroxyl radical formation, although it is possible that there exists a genetic linkage of Tf variant to some other locus which is influencing susceptibility to RA.