INFLUENZA VACCINE MAY INDUCE AUTO-REACTIVE IgG ANTIBODIES DETECTABLE IN FLOW CYTOMETRY CROSSMATCHES.
TY Cooper, J Avandsalehi, P Hymel, T Barnes, A Thomas, R Sellers, K Brooks, M Noor, SM Qiu, K Gugliuzza, J Daller, and S Vaidya Departments of Pathology and Surgery, The University of Texas Medical Branch, Galveston, Texas.
A 66-year-old Caucasian male was evaluated at our center for renal transplantation from his daughter. Preliminary workup revealed that the daughter was a one-haplotype match (patient's HLA: A2, 3; B35(w6), 62(w6); Cw3,4; DR1,4; DQ1,8 - daughter's HLA: A2; B55(w6), 62(w6); Cw3; DR4; DQ7,8). Initial allo and auto T and B cell cytotoxicity crossmatches were negative. The patient received an influenza vaccine ("flu shot") two weeks prior to his scheduled transplant. T and B cell (allo) flow cytometry crossmatching, using a FITC-anti IgG conjugate, performed one day prior to the scheduled transplant were positive with sera drawn post-influenza vaccine and negative with sera drawn pre-influenza vaccine. All cytotoxicity crossmatches were negative with pre and post influenza vaccine sera. We then performed auto-flow crossmatches and found similar results in that pre-influenza vaccine sera were flow crossmatch negative while post-influenza vaccine sera were flow crossmatch positive. The transplant was postponed pending further investigation.
Auto-absorption (X2) of patients sera reduced autologous T and B flow crossmatch reactivity but not to the point of negativity. Mean channel shifts (MCS) were reduced from 74 to 34 for T-FCXMs and from 64 to 37 for B-FCXMs after auto-absorption - our positivity cutoffs for T and B FCXMs are 20 MCS and 30 MCS, respectively, using 256-channel resolution. The pre and post influenza vaccine sera were tested against HLA specific microparticles (Flow PRA, One lambda, Inc, Canoga Park, CA) and found to be negative for both HLA class I and class II antibodies.
The patient was transplanted with his daughter's kidney approximately three months after his influenza vaccine due to the lack of HLA specific antibodies although T and B flow crossmatches remained positive at the time of transplantation. The graft functioned immediately and the patient was discharged four days afterward with a creatinine of 1.7 mg/dl. The patient has remained rejection-free through four months of follow up and has maintained serum creatinine levels of 1.5-1.7 mg/dl on immunosuppressive therapy consisting of FK-506, prednisone and mycophenolate mofetil. This case illustrates the need to investigate unexpected positive flow cytometric crossmatches before ruling out transplantation.