[Mono- and oligoclonal immunoglobulin anomalies in kidney transplant patients].

Serum from 115 HIV negative renal transplant recipients having more than 6 months follow-up was tested for the presence of mono- or oligoclonal immunoglobulins (moIg) by immunoelectrophoresis or immunofixation. Mono/oligoclonal gammapathy was detected in 16 patients (13.9%). Eight of these patients had only one monoclonal band, whereas the other eight had two or more bands. Thirteen of the 16 patients (81.3%) were IgG kappa positive, nine (56.3%) were IgG lambda positive, four (25.0%) were IgM lambda positive and only one (6.3%) was IgM kappa positive. Six monoclonal patients (37.5%) were IgG kappa positive and two monoclonal patients (12.5%) were IgG lambda positive. The oligoclonal combination IgG kappa lambda was present in three patients (18.8%), the combination IgG lambda + IgM lambda was present in two patients (12.5%) and IgG lambda + IgM lambda was present in one patient. The triple combination IgM kappa lambda + IgG kappa lambda and IgM lambda + IgG kappa lambda was found in two patients (12.5%). Ninety percent of these moIg did not exceed 2 g/L. MoIg appeared between 1 and 28 months after the kidney transplantation (mean value: 8.5 5.9 months) but were often transient, disappearing within 1 to 19 months in 13 patients (81.3%). Nine of the 16 cases (56.3%) disappeared before the end of the first year after detection. Risk factors for the appearance of these immunoglobulins have been identified as: the patient's age, the duration of haemodialysis, the occurrence of prior (anti-cytomegalovirus [CMV]) infection, and therapy with cyclosporin A (CsA). The persistence of monoclonal gammapathy was associated with acute or reactivated Epstein-Barr virus (EBV) infection and inability to convert IgM to IgG CMV antibodies. Furthermore, no association was established with previous hepatitis B or C infection or the number of rejection episodes. Kaposi's sarcoma was found in one patient (6.3%) but had no correlation with the presence of moIg. We recommend careful follow up of renal transplant patients in whom moIg have been discovered.