Increased prevalence of apolipoprotein E3/E4 genotype among Swedish renal transplant recipients

There is increasing evidence that lipoproteins are involved in the progress ion of kidney diseases and in the deterioration of kidney transplant functi on, although the exact mechanism is still not known. Common polymorphisms o f apolipoprotein E genotype associate with the variability of lipoprotein l evels and composition. We have, therefore, determined the apolipoprotein E genotype in a group of 112 renal transplant patients, of whom 27 had had an episode of acute vascular rejection, while 85 had not. We found no differe nce in apolipoprotein E genotype distribution or in relative allele frequen cy in the vascular rejection group as com pa red with the group without vas cular rejection. The apolipoprotein E genotype distribution in the transpla nt group was also compared with that in a group of 407 healthy Swedish indi viduals. The E3/E4 genotype occurred with a significantly increased frequen cy in the transplant group: 38.3 versus 16% in the control group (p < 0.001 ). The prevalence of individuals carrying the epsilon 4 allele among the tr ansplant group was also significantly higher (44%) as compared with the con trol group (30%; p < 0.01). This increase was entirely due to the predomina nt increase of E3/E4, as the E4/E4 genotype was less frequent in transplant recipients than in normal controls (3.5 vs. 10.6%; p < 0.05). The relative frequencies of epsilon 2 (0.044), epsilon 3 (0.716), and epsilon 4 (0.238) alleles in the renal transplant group were not different from those of nor mal controls (0.078, 0.718, and 0.202, respectively). With regard to the pr evalence of E4/E4 in the two groups, the lack of difference in the relative frequency of the epsilon 4 allele must be interpreted with caution. The re sults thus suggest that the E3/E4 genotype may be associated with the progr ession of kidney disease leading to renal insufficiency. However, the apoli poprotein E genotype does not seem to influence the risk of vascular reject ion among transplant recipients.