primary biliary cirrhosis ( pbc ) is a chronic and progressive cholestatic liver disease characterized by destruction of small- to medium - sized bile ducts . it is an autoimmune disease characterized by circulating anti - mitochondrial antibodies ( ama ) . asymptomatic distal tubular acidosis ( dta ) is the most common renal lesion associated with pbc and may occur in up to one - third of patients with the disease . more rarely fanconi syndrome , membranous nephropathy , microscopic polyangiitis and tubulointerstitial nephritis ( tin ) have also been reported in patients with pbc [ 25 ] . tin is a disorder characterized by inflammatory infiltrate which occurs mostly in the tubules and interstitium . chronic tubulointerstitial nephritis ( ctin ) is associated with a number of diseases of diverse aetiology and is characterized by tubular cell atrophy , flattening of epithelial cells and tubular dilatation , interstitial fibrosis and areas of mononuclear cell infiltration within the interstitial compartment and between the tubules . the association between tin and pbc was first reported in 1987 by macdougall et al . although it appears to be an extremely rare association with only a handful of cases published in the literature since then [ 510 ] . pbc is not considered to be an inherited disorder , although there have been reports of multiple cases occurring in a single family . to our knowledge , tin leading to chronic kidney disease ( ckd ) in genetically linked patients with pbc has not been previously reported . we report a case of ckd due to ctin occurring in both mother and daughter who have liver biopsy - proven pbc and review the current literature of tin in patients with pbc . a 46-year - old female patient was referred for nephrology assessment in october 2011 for progressive ckd with a creatinine level of 207 mol / l ( estimated glomerular filtration rate , egfr 22 ml / min/1.73 m ) . she had previously been diagnosed with pbc on liver biopsy in 2004 and was under regular follow - up with a hepatologist . she was otherwise well and was in full - time employment as an office manager . her mother was also diagnosed with pbc on liver biopsy in 1997 and underwent renal biopsy for progressive ckd in 2001 at another tertiary centre which showed tin . the patient 's mother was treated with long - term low - dose steroid therapy for ctin which had successfully stabilized her renal function . systemic examination of the patient was unremarkable , blood pressure was 119/72 mmhg , and urine dipstick showed no blood or protein . the rest of the immunology screen including anti - nuclear antibody - hep2 , centromere antibody , anti - smooth muscle antibodies and liver kidney microsomal antibody was negative . a kidney biopsy was performed to establish a diagnosis and revealed a chronic active tin associated with mild oedema and moderately widespread established fibrosis ( figure 1 ) . the patient was started on 40 mg of oral prednisolone that has now been tapered off to a maintenance dose of 5 mg daily . her renal function has improved on steroids and she currently has stable ckd ( figure 2 ) . 
 fig . 2.patients ' egfr ( modification of diet in renal disease ) before and after treatment . patients ' egfr ( modification of diet in renal disease ) before and after treatment . occurrence of multiple cases in a single family is well recognized and different series have shown prevalence of familial pbc ranging from 1.33% to 5.5% . this familial predisposition to pbc is complex and polygenic . hla association of pbc is well recognized and many loci have been identified . an association has been suggested between pbc and haplotypes hla - dr8 and hla - dpb1 . in patients with familial pbc , maternal inheritance is most common and might be linked to mitochondrial dna that is always maternally inherited . one - third of patients with advanced pbc are recognized to have dta that normally has no clinical significance . tin , an inflammatory renal disease characterized by lymphocytic infiltration of interstitium and tubules , has rarely been described in these patients . in a review of the literature , lino et al . identified four patients with tin and pbc . they suggested a possible role of ama in the pathogenesis of renal disease during pbc . lino et al . suggested that abnormal antigen expression may occur in renal tubular cells and this may lead to infiltration of the renal interstitium by autoreactive t - cells causing tin . in our patient , there was no evidence of associated renal tubular acidosis . reviewed 5955 renal biopsies performed over a 30-year period in a single centre and identified four patients with tin associated with asymptomatic pbc . kidney biopsy in all four cases showed severe tubulointerstitial cell infiltration , tubulitis and mild - to - moderate interstitial fibrosis and tubular atrophy . in the review of the literature , they identified nine biopsy - proven cases of tin in association with pbc ( including four reported in their case series ) . eight patients had an abnormal renal function , seven of whom showed a good clinical response to a moderate dose of steroids ( 2530 mg prednisolone ) . in the remaining two patients , tin is now identified as a rare but important extra - hepatic manifestation of pbc . to our knowledge , there are no previous reports of familial presentation of tin in association with pbc . the incidence of ckd in familial pbc is not reported in the literature owing to the rarity of this occurrence . it is also not clear how long steroids should be continued . in our case , it is worth noting that the mother 's kidney function deteriorated when steroids were withdrawn and improved when steroids were restarted , and therefore , we have made an elective decision to maintain our patient on long - term low - dose steroids . further case reports and registry - based data could help to establish the familial inheritance of tin in pbc and management strategies in these patients .
primary biliary cirrhosis ( pbc ) is an autoimmune disease characterized by the presence of anti - mitochondrial antibodies ( ama ) . whilst asymptomatic distal tubular acidosis ( dta ) 
 is the commonest renal lesion reported in pbc , tubulointerstitial nephritis ( tin ) has also been reported as a rare association . 
 although pbc could be a familial disorder , there have been no previous reports of familial chronic tin in association with pbc . 
 we report a case of progressive chronic kidney disease ( ckd ) due to tin in a mother and daughter known to suffer from pbc and review the previously reported literature . 
 both showed good response to steroids .