HLA associations with tubulointerstitial nephritis with or without uveitis in Finnish pediatric population: a nation-wide study

The human leukocyte antigen (HLA) genotype has been shown to associate with tubulointerstitial nephritis (TIN) and tubulointerstitial nephritis with uveitis syndrome (TINU). The association of HLA genes with TIN was examined in this nation‐wide study. HLA genotyping was performed in 31 pediatric patients with biopsy‐proven TIN. All patients were examined by an ophthalmologist to diagnose possible uveitis. Class II HLA genotypes of TIN patients were compared with the Finnish reference population. We found a significant association between the HLA alleles DQA1*04:01 [risk ratio (RR) 5.0, 95% confidence interval (CI) 2.0–11.2], DQB1*04:02 (RR 2.7, 95% CI 1.4–5.3), and DRB1*08 (RR 3.8, 95% CI 1.5–8.4) and TIN. Uveitis was found in 20/31 (64.5%) patients. HLA genotyping of the TINU patients showed additional risk HLA alleles: DQA1*01:04 (RR 6.1, 95% CI 1.5–17.8), and DRB1*14 (RR 8.2, 95% CI 2.2–22.1). The alleles DQA1*01:04 (RR 8.8, 95% CI 2.2–26.5), DQA1*04:01 (RR 3.2, 95% CI 1.2–7.3), and DRB1*14 (RR 12.0, 95% CI 3.2–33.0) were more frequent in patients with TIN and chronic uveitis than in reference population. The HLA class II haplotype DQA1*04:01/DQB1:04:02/DRB1*08 was the most common combination in our study population (58.1%). None of the patients had haplotype DQA1*04:01/DQB1*06:02/DRB1*15, which is common in Finland. HLA genotype did not predict the renal outcome. We found a strong association between certain HLA genotypes both in TIN and TINU patients. The TIN/TINU‐associated HLA alleles appear to vary depending on study population.