Prevalence of cryoglobulinemia and autoimmunity markers in renal-transplant patients

Abstract

To examine the prevalence of cryoglobulinemia (Cryo) and autoimmune markers in renal-transplant recipients in a stable condition, and to determine its risk factors and impact upon allograft function. In May, 2006, 117 kidney-transplant (KT) recipients, aged 31 â 76 years, were tested for cryoglobulinemia, hepatitis B and C, complement C3, C4, CH50, antinuclear (ANAs), anticytoplasmic nuclear (ANCAs) and anticardiolipid antibodies, rheumatoid factor (RF), and lymphocyte subpopulations. Renal, liver, and hematological tests were also performed. Immunosuppressive regimens were based on calcineurin inhibitors (82%). Cryo was positive in 47 patients (Cryo(+): 40.2%), of whom 13 were HCV+ (27.7%), with characteristics of Type II in 21.2% and Type III in 78.8%. Cryo was positive in 13/16 (81.2%) of HCV+/RNA+ patients vs. 34/101 (33.6%, p = 0.0003) of HCV-negative patients. Cryo(+) RT patients had been recipients of a graft for longer (142 months) than Cryo(-) patients, i.e., 95 months (p = 0.02). Creatinine clearances were similar in the two groups (56 vs. 50 ml/mn, p = 0.5), as were microalbuminuria and albuminemia. There was no difference between Cryo(-) and Cryo(+) patients in terms of age, sex, HLA mismatch, daily steroid doses, liver and hematological tests, ANAs, anticardiolipid antibodies, serum complement, and lymphocyte subpopulations. RF occurred in all Cryo(+) patients and in 82.8% of Cryo(-) patients, with higher titers in the Cryo(+) group (23 vs. 9 UI/ml, p = 0.012). ANCA occurred in nine Cryo(-) but in no Cryo(+) patients (p = 0.013). Finally, a multivariate analysis was not able to determine any predictive factor associated with cryoglobulinemia. Cryoglobulinemia is frequent after KT, and is associated with HCV markers, RF, and absence of ANCA.