Comparison of monoclonal and polyclonal anti-P1 reagents

Whereas monoclonal reagents for ABO, Rhesus, Kell, Kidd, Lewis and MNS antigens are widely used in blood grouping laboratories and have been well evaluated, little attention has been given so far to monoclonal anti-P1 reagents. Therefore it was the aim of our study to examine the suitability of monoclonal anti-P1 reagents for routine use in comparison to polyclonal anti-P1 reagents. 10 polyclonal anti-P1 reagents (9 from goat, 1 from rabbit) and 5 monoclonal anti-P1 reagents (4 with clone 650, 1 with clone OSK17) were tested by the tube-spin-method at room temperature (incubation time as prescribed by the manufacturer) using untreated P1+ red blood cells (RBCs) for titration and untreated P1- RBCs as negative controls. P1- RBCs with a positive direct anti-globulin test (DAT+) (coated with incomplete anti-D) and sialidase-treated P1- RBCs (T+) were used to recognize false positive reactions. 3 monoclonal anti-P1 reagents had a titer of < or = 1 with P1+(weak) RBCs, but all polyclonal anti-P1 reagents showed a titer > or = 2. Negative controls (untreated P1- RBCs) were inconspicuous. 7 polyclonal and 1 monoclonal anti-P1 reagents showed false positive reactions with P1- DAT+ RBCs. All polyclonal and 1 monoclonal (containing clone OSK17) reagent showed false positive reactions with P1- T+ RBCs. As several monoclonal anti-P1 reagents are less suitable for routine use than polyclonal anti-P1 reagents, quality control of anti-P1 reagents should be intensified.