The major aim of the DeKAF study was to define previously unidentified phenotypes resulting in late graft dysfunction and loss (GL). Two cohorts were developed, each with late (>3 mos) graft dysfunction (>25% rise in SCr level or new onset proteinuria) leading to an "index" biopsy: a) Cross-sectional cohort (CS), tx prior to 10/1/05 and having SCr ≤2 mg/dl on 1/1/06 (n =503); and b) Prospective cohort (PS), tx between 10/6/05 and 6/10/10 (n with index bx =358). Avg follow-up was 3.6 yrs. All bx were read by a blinded central pathologist (including blinded as to cohort), and scored using extended Banff criteria. Histologic interpretation was done without C4d or DSA information. Mean time from tx to bx for CS-cohort (±SD) was 7.5±5.4 yrs; for PS, 1.21 yr. Median Cr (IQR) at bx for CS was 2.1 (1.7,2.8); PS, 2.2 (1.8,3) (NS). Post-bx graft survival did not signif diff between cohorts for 3 yrs (@2 yrs: 75% CS vs 78% PS, @3 yrs: 69% CS vs 75% PS), becoming significantly lower at 4 yrs: 61% CS vs 72% PS; 5 years (57% CS vs 69% PS). Table 1 shows the individual Banff scores by cohort; all but g and ptc were signif diff between cohorts. Table 2 lists the individual primary and secondary diagnoses by cohort. Acute injury was more common in the PS-cohort (signif more ATN, CMR, borderline or minimal changes), whereas chronic injury (with or without acute injury) was more common in the CS-cohort (signif more TG, arteriolar hyalinosis, and inflammation in areas of fibrosis). We conclude that in spite of differences in histology between the CS- and PS-cohorts, an index bx for both was associated with ~25% GL within 2 yrs. Although there was considerable overlap, different phenotypes in Cs vs PS cohorts may be responsible for late GL.

CITATION INFORMATION: Matas A, Fieberg A, Hunsicker L, Grande J, For the DeKAF Group Long-Term Deterioration of Graft Function (DeKAF) Study: Histologic Interpretation of Cross-sectional vs Prospective Cohorts. Am J Transplant. 2016;16 (suppl 3).

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