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Abstract: TH-PO124

Predictive Factors of Renal Involvement in Cryoglobulinemia: A Retrospective Study of 153 Patients

Session Information

Category: Glomerular

  • 1004 Clinical/Diagnostic Renal Pathology and Lab Medicine

Authors

  • Coliche, Vladimir, Hospices Civils de Lyon, Lyon 1 University, Lyon, France
  • Lega, Jean-Christophe, Hospices Civils de Lyon, Lyon 1 University, Lyon, France
  • Laville, Maurice, Hospices Civils de Lyon, Lyon 1 University, Lyon, France
  • THERY-CASARI, Clemence, Hospices Civils de Lyon, Lyon 1 University, Lyon, France
  • Trolliet, Pierre, Hospices Civils de Lyon, Lyon 1 University, Lyon, France
  • Nouvier, Mathilde, Hospices Civils de Lyon, Lyon 1 University, Lyon, France
  • Grégoire, Basse, Hospices Civils de Lyon, Lyon 1 University, Lyon, France
  • Sarda, Marie N, Hospices Civils de Lyon, Lyon 1 University, Lyon, France
  • Fouque, Denis, Hospices Civils de Lyon, Lyon 1 University, Lyon, France
Background

The course of cryoglobulinemia varies widely, from asymptomatic patients to severe vasculitis. Renal involvement (RI) is a major prognostic factor, and frequently occurs several years after diagnosis. Twenty to 56% of patients will develop RI. Predictive factors of RI have not been studied. The aim of our study was to identify factors associated with RI occurence in patients with cryoglobulinemia.

Methods

We retrospectively reviewed the clinical charts of a consecutive series of 153 patients positive for cryoglobulinemia (from January 2012 to December 2014) in the University Hospital of Lyon (France). Immunoglobulin (Ig) G, IgM and IgA concentrations as well as rheumatoid factor (RF) activity were assessed in cryoprecipitate. Complement fractions C3 and C4, CH50 activity and RF were simultaneously assayed in sera. RI was defined either histologically, or biologically if cryoglobulinemia was the only possible cause of nephropathy (proteinuria > 0.5 g/24h or hematuria > 10/mm3 or eGFR < 60 ml/min/1.73m2 CKD-EPI).

Results

Among the 153 positive measures (mean age 55 years, male gender 37%), cryoglobulinemia was associated with RI in 45 pts (29.4%). The presence of IgA in cryoprecipitate was very significantly associated with RI (22% in RI group vs 1% in control group, p<0.0001) contrary to IgG or IgM. Type 3 cryoglobulinemia was more frequent in controls than in RI group (35% vs 11%, p=0.006). Regarding etiology, only B-cell lymphoma was statistically associated with RI (22% vs 9%, p=0.03), there was no difference for hepatitis C virus. RF activity was more frequent (42% vs 24%, p=0.03) and cryoglobulin total Ig concentration was higher (137 mg/l vs 39 mg/l, p=0.001) in case of RI, whereas C3 and C4 were similar. There were more men in RI group (60% vs 27%, p<0.0001), and slightly more patients had cutaneous purpura (38% vs 22%, p=0.048).

Conclusion

Several factors may be associated with the occurrence of RI in cryoglobulinemia (IgA, B-cell lymphoma, purpura), whereas type 3 cryoglobulinemia appears to be protective. In these at risk patients, kidney function monitoring and nephroprotection might be intensified. Further studies are needed to confirm these findings and understand mechanisms of theses associations with RI.