The effectiveness of the combination of rituximab and high-dose immunoglobulin in the immunomodulation of sensitized kidney transplant candidates.

Kidney transplantation faces many challenges not the least of which is the presence of pre-formed HLA antibodies. At our institution, we have used a combination of methods to immunomodulate sensitized patients. Most recently, this has been attempted with a combination of immunoglobulin (IVIG) and rituximab (Rituxan; Genetech, CA, USA). A total of 31 patients were followed for up to one yr following treatment with IVIG (2 gm/kg on day 1 and day 30) and rituximab (1 g - day 15). Antibody levels were followed serially at designated time points via solid-phase single-antigen beads (SAB) method (One Lambda, Inc., Canoga Park, CA, USA). Concentration of antibodies was based on median fluorescence intensity (MFI). The majority of patients had both class I and class II antibodies (79%). Our results showed that this protocol appeared to be patient and antibody specific. The most pronounced MFI reduction in antibodies occurred within the 30- to 100-d period post-treatment. Calculated panel-reactive antibodies decreased but rebound tended to occur by 104 d after antibody MFI nadir. Because of this rebound, it can be inferred that the patients did not show a durable increase in their potential for transplantation. The search for a more effective method to immunomodulate patients continues.