Immune cells in the anterior chamber of patients with immune reactions after penetrating keratoplasty

Purpose. Lymphocytes, monocytes, and macrophages are the predominating immune cells in graft rejection after keratoplasty in animal models. This study focuses on the isolation of immune cells from the anterior chamber of patients with slight, moderate, and severe endothelial immune reactions after penetrating keratoplasty. Methods. Anterior chamber puncture was performed in five patients with cataract without inflammation and without penetrating keratoplasty (C1), in three patients undergoing penetrating keratoplasty without immune reactions (C2), in four patients undergoing penetrating keratoplasty after complete resolution of endothelial immune reactions (C3), in seven patients undergoing penetrating keratoplasty with slight endothelial immune reactions (IM1), in 10 patients undergoing penetrating keratoplasty with moderate endothelial immune reactions (IM2), and in eight patients undergoing penetrating keratoplasty with severe endothelial immune reactions (IM3). In each patient, approximately 0.1 mL of aqueous humor was examined. Cells in suspension were directly centrifuged on glass slides using a Cytospin centrifuge, stained, and evaluated under the light microscope. Results. Groups C1, C2, and C3 did not contain cells. Immune cells were identified in three of seven patients in IM I, in eight of 10 patients in IM2, and in eight of eight patients in IM3. Predominating cells were macrophages and monocytes followed by lymphocytes. Regarding all patients in IM1, IM2, and IM3, a statistically significant correlation between detected cells and patient age, period between penetrating keratoplasty and anterior chamber puncture, or period between first symptoms and anterior chamber puncture could not be revealed. Granulocytes were found statistically significantly less often in patients with high-risk indications, in patients with a history of immune reactions and under immunosuppression. Lymphocytes were found statistically significantly less often in patients with a history of immune reactions. Conclusions. The probability to isolate immune cells from the anterior chamber of patients undergoing penetrating keratoplasty correlates with the severity of the endothelial immune reactions. This study is a first step to evaluate how detailed immunologic findings from animal keratoplasty models fit to clinical reality in patients undergoing keratoplasty. In the next step, cells found in the aqueous humor of patients with endothelial immune reactions should be further characterized directly (determination of molecules on the surface of the cells) or indirectly (determination of cytokine levels in the aqueous humor).