Detection of anti-HLA antibody by flow cytometry in patients with a left ventricular assist device is associated with early rejection following heart transplantation.
BACKGROUND
Patients with a left ventricular assist device (LVAD) as a bridge to heart transplantation (HT) often have elevated levels of panel reactive antibodies (PRA). The clinical significance of anti-human histocompatibility leukocyte antigen (HLA) antibodies detected by flow cytometry in PRA negative patients remains unclear.


METHODS
Eighteen patients who underwent LVAD placement as a successful bridge to HT had standard anti-human globulin complement-dependent cytotoxicity and retrospective flow cytometry assays performed to detect class I anti-HLA antibodies. A positive flow result was defined as a fluorescent ratio of 23:1 versus a negative control.


RESULTS
Six patients had anti-HLA antibodies detected by flow cytometry. Univariate analysis demonstrated more moderate-severe rejection episodes (ISHLT > or = IIIA) at 2 months (0.83+/-0.75 vs. 0; P=0.04) and a trend toward decreased time to first rejection (61+/-17 vs. 225+/-62 days; P=0.06) in these patients. No differences were observed in donor-recipient HLA mismatch or 1 year Kaplan-Meier survival between patients with or without anti-HLA antibodies.


CONCLUSIONS
Despite a negative PRA, LVAD patients with class I anti-HLA antibodies detected by flow cytometry have a greater incidence of moderate-severe rejection in the first 2 months after HT. Flow cytometry may be a useful clinical tool in screening PRA negative LVAD patients before transplantation. Patients with positive anti-HLA antibody screening by flow cytometry may require more intensive immunosuppression in the early post-HT period.
DeNofrio
D
D
Department of Medicine, University of Pennsylvania Health System, Philadelphia 19104, USA.
Rho
R
R
Morales
F J
FJ
Kamoun
M
M
Kearns
J
J
Dorozinsky
C
C
Rosengard
B R
BR
Acker
M A
MA
Loh
E
E
D000328:Adult; D000906:Antibodies / Q000032:analysis*; D005260:Female; D005434:Flow Cytometry; D006084:Graft Rejection; D006680:HLA Antigens / Q000276:immunology*; D016027:Heart Transplantation; D006353:Heart-Assist Devices; D006650:Histocompatibility Testing; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016019:Survival Analysis; D013997:Time Factors; D016277:Ventricular Function, Left
D000906:Antibodies; D006680:HLA Antigens