P  A  M  E  T  -  N  E  V  A  D  A

PHILIPPINE ASSOCIATION OF MEDICAL TECHNOLOGISTS - NEVADA, INC.

"To serve the community, the profession, and the person."

H.P.C.

(HUMAN PLATELET CONCENTRATE)

By DENNIS HARRIS, Blood Bank MT

      HLA related antibodies are often found in the sera of multiple transfused persons and mutiparous women. Because these antibodies cause the agglutination of red cells, they can interfere in the detection or identification of other clinically significant antibodies that may also be present. Absorbing a specimen to diminish or remove the activity of HLA related antibodies assists in the identification of clinically significant antibodies

     Platelets, a source of HLA antigens, do not  carry most of the red cell antigens. Though the degree of expression varies greatly, HLA-A, B, and C antigens are expressed on platelet surfaces, making platelets an excellent adsorption material for the removal of HLA related antibodies. Performing adsorptions with pools of platelets from many donors increases the probability that adequate quantities of HLA antigens are present to allow efficient adsorption of antibody.

     Reactions between an antigen and its antibody can be diminished or removed if the serum containing the antibody is first incubated with an adsorbent carrying the appropriate antigen receptor. H.P.C. is rehydrated with the serum suspected of containing HLA related antibodies and incubated at room temperature for 15 minutes. During the incubation, HLA related antibodies will bind to platelet HLA antigens present in H.P.C.

    After adsorption with H.P.C. retesting of the sample may demonstrate negative or weakened reactions with red cells that had previously given positive reactions. By comparing pre and post adsorption results it may be possible to detect and identify other alloantibodies. In some cases there may be no change in reactivity suggesting the reactions were not due to HLA related antibodies or incomplete adsorption of HLA antibodies by the H.P.C.

    Caution should be used as some antibodies such as Lea, Leb, and Fya may be adsorbed. Therefore, test-employing H.P.C. adsorbed serum should not be the only tests used for antibody detection.

H.P.C. is a dry preparation of a washed pool of platelets from individual human platelet donors. Product of Immucor, Inc.

Immucor product insert Rev.7/99

AABB Technical Manual 13th Edition

Modern Blood Banking and Transfusion Practices 4th Edition