CLINICAL-FEATURES, PREDICTORS OF DISEASE PROGRESSION AND RESULTS OF RENAL-TRANSPLANTATION IN FIBRILLARY IMMUNOTACTOID GLOMERULOPATHY/

Background. The clinical manifestations of fibrillary-immunotactoid gl omerulopathy are still being appreciated. It is unclear whether fibril lary-immunotactoid glomerulopathy represents two distinct clinicopatho logical entities, fibrillary glomerulopathy (FG) immunotactoid glomeru lopathy (ITG), or a single disease with different ultrastructural vari ants. Methods. To address these issues, we analysed the clinical featu res of 186 patients with fibrillary-immunotactoid glomerulopathy refer red to our institutions (25 patients) or reported in the literature (1 61 patients). In separate analyses, patients were subclassified as hav ing either fibrillary glomerulopathy (FG) or immunotactoid glomerulopa thy (ITG) according to fibril diameter (FG less than or equal to 30 nm , ITG>30 nm) or arrangement (FG, random; ITG, focally organized). Resu lts. Proteinuria (FG similar to 100%, ITG similar to 100%), nephrotic syndrome( FG similar to 71%, ITG similar to 82%), haematuria (FG simil ar to 71%, ITG similar to 64%), hypertension (FG similar to 67%, ITG s imilar to 45%), and renal insufficiency (FG similar to 54%, ITG simila r to 42%) were frequent clinical correlates of both FG and ITG, irresp ective of the ultrastructural criteria for diagnosis. Twenty-five pati ents presenting to our institutions (24 FG, 1 ITG) were divided into t hree groups based on rate of decline of GFR (mean slope of 1/serum cre atinine versus time: group 1 -0.103+/-0.238; group 2 0.121+/-0.040; gr oup 3 0.466+/-0.318) in an attempt to identify clinical predictors of progression at presentation. Rapid progressors (Group 3) had an increa sed incidence of nephrotic syndrome and tended to have higher blood pr essure than patients with milder disease, but did not differ from othe r groups in age, prevalence of haematuria or degree of renal insuffici ency. The number of patients requiring dialysis was 0/10 in group 1, 2 /6 in group 2, and 2/4 in group 3 over a follow-up period of 47+/-46, 55+/-32, and 19+/-19 months respectively; two predialysis deaths being recorded in group 3. Four patients received five renal allografts (on e patient being transplanted twice) and were followed for 4-11 years. Whereas recurrence of FG was documented in three allografts undergoing post-transplant biopsy, the rate of deterioration of GFR was invariab ly slower in allografts than native kidneys (mean slope of 1/Cr versus time: 0.036+/-0.01 versus 0.301+/-0.18 respectively). The strength of association between FG-ITG and lymphoproliferative malignancy varied depending on whether patients with monoclonal-gammopathy-associated fi brillary deposits were included or excluded from the analysis. Conclus ions. We contend that patients presenting with Congo-red-negative fibr illary deposits on renal biopsy should be evaluated carefully for mono clonal gammopathy and cryoglobulins, but that there is insufficient pu blished data, as yet, to justify subclassification of FG and ITG as di stinct clinicopathological entities. Indeed, we argue that it remains to be determined if FG-ITG represents a unique condition or a forme fr uste of cryoglobulin- or monoclonal-gammopathy-associated renal diseas e. Although the optimal treatment for FG-ITG has not been determined, renal transplantation appears an attractive option in patients with en d-stage renal failure.