Detection and significance of granulocyte alloimmunization in leukocyte transfusion therapy on neutropenic dogs

An indirect flow cytometric test for detection of anti-neutrophil antibodies in dogs

OBJECTIVE

To develop a clinically applicable assay for detection of serum anti-neutrophil antibodies in dogs.

SAMPLE POPULATION

Serum samples of 20 healthy dogs and 20 sick dogs.

PROCEDURES

An indirect immunofluorescence assay was developed in which canine serum was incubated with paraformaldehyde-fixed neutrophils and subsequently incubated with fluorescein-conjugated rabbit anti-dog IgG. Neutrophil median fluorescence intensity and the percentage of neutrophils with an increase in fluorescence intensity were determined by use of a flow cytometer.

RESULTS

Neutrophils incubated with serum from healthy and sick dogs had a normally distributed curve when displayed as a histogram. Alloantibodies or immune complexes that significantly affected test results were not detected. Hyperglobulinemia did not appear to affect test results. The neutrophil donor did not significantly affect test results. With 1 exception, results for the sick dogs did not differ appreciably from those for healthy dogs. Serum from a dog with steroid-responsive neutropenia had a greater neutrophil fluorescence value and percentage of neutrophils with an increase in fluorescence intensity, compared with either healthy or sick dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

The indirect immunofluorescence test gave consistent results for healthy and sick dogs and detected anti-neutrophil antibodies in a dog with steroid-responsive neutropenia. Definitive evaluation of the test will be dependent on evaluation of persistently neutropenic dogs and correlation of test results with a response to immunosuppressive therapy.

Effect of leukocyte compatibility on neutrophil increment after transfusion of granulocyte colony-stimulating factor–mobilized prophylactic granulocyte transfusions and on clinical outcomes after stem cell transplantation

The primary limitations of granulocyte transfusions include low component cell dose and leukocyte incompatibility. Component cell dose improved with granulocyte colony-stimulating factor (G-CSF) mobilization, and the transfusion of G-CSF–mobilized, human leukocyte antigen (HLA)-matched granulocyte components resulted in significant, sustained absolute neutrophil count (ANC) increments. However, the effect of leukocyte compatibility on outcomes with G-CSF–mobilized granulocyte transfusions is unclear. The objectives were to determine the effect of leukocyte compatibility on ANC increments and selected clinical outcomes after transfusion of prophylactic, G-CSF–mobilized granulocyte components into neutropenic recipients of autologous peripheral blood stem cell (PBSC) transplants. Beginning on transplant day 2, 23 evaluable recipients were scheduled to receive 4 alternate-day transfusions of granulocyte components apheresed from a single donor given G-CSF. G-CSF was also given to recipients after transplantation. Recipient ANC was determined before and sequentially after each granulocyte transfusion to determine the peak ANC increment. Leukocyte compatibility was determined at study entry only by a lymphocytotoxicity screening assay (s-LCA) against a panel of HLA-defined cells. Eight recipients had positive s-LCA. On days 2 and 4, the mean peak ANC increments after granulocyte transfusion were comparable between the cohorts with positive and negative s-LCA. However, the mean peak ANC increments on day 6 (246/μL vs 724/μL; P = .05) and day 8 (283/μL vs 1079/μL; P = .06) were lower in the cohort with positive s-LCA, in spite of the transfusion of comparable component cell doses. Adverse reactions occurred with only 5 of 87 (5.7%) granulocyte transfusions and were not associated with leukocyte compatibility test results. Platelet increments, determined 1 hour after granulocyte transfusion, were comparable between the cohorts. Although the 2 cohorts received PBSC components with similar CD34+ cell doses, the cohort with a positive s-LCA had delayed neutrophil engraftment and a greater number of febrile days and required more days of intravenous antibiotics and platelet transfusions. Leukocyte incompatibility adversely affected ANC increments after the transfusion of G-CSF–mobilized granulocyte components and clinical outcomes after PBSC transplantation.

Effect of leukocyte compatibility on neutrophil increment after transfusion of granulocyte colony-stimulating factor–mobilized prophylactic granulocyte transfusions and on clinical outcomes after stem cell transplantation

The primary limitations of granulocyte transfusions include low component cell dose and leukocyte incompatibility. Component cell dose improved with granulocyte colony-stimulating factor (G-CSF) mobilization, and the transfusion of G-CSF–mobilized, human leukocyte antigen (HLA)-matched granulocyte components resulted in significant, sustained absolute neutrophil count (ANC) increments. However, the effect of leukocyte compatibility on outcomes with G-CSF–mobilized granulocyte transfusions is unclear. The objectives were to determine the effect of leukocyte compatibility on ANC increments and selected clinical outcomes after transfusion of prophylactic, G-CSF–mobilized granulocyte components into neutropenic recipients of autologous peripheral blood stem cell (PBSC) transplants. Beginning on transplant day 2, 23 evaluable recipients were scheduled to receive 4 alternate-day transfusions of granulocyte components apheresed from a single donor given G-CSF. G-CSF was also given to recipients after transplantation. Recipient ANC was determined before and sequentially after each granulocyte transfusion to determine the peak ANC increment. Leukocyte compatibility was determined at study entry only by a lymphocytotoxicity screening assay (s-LCA) against a panel of HLA-defined cells. Eight recipients had positive s-LCA. On days 2 and 4, the mean peak ANC increments after granulocyte transfusion were comparable between the cohorts with positive and negative s-LCA. However, the mean peak ANC increments on day 6 (246/μL vs 724/μL; P = .05) and day 8 (283/μL vs 1079/μL; P = .06) were lower in the cohort with positive s-LCA, in spite of the transfusion of comparable component cell doses. Adverse reactions occurred with only 5 of 87 (5.7%) granulocyte transfusions and were not associated with leukocyte compatibility test results. Platelet increments, determined 1 hour after granulocyte transfusion, were comparable between the cohorts. Although the 2 cohorts received PBSC components with similar CD34+ cell doses, the cohort with a positive s-LCA had delayed neutrophil engraftment and a greater number of febrile days and required more days of intravenous antibiotics and platelet transfusions. Leukocyte incompatibility adversely affected ANC increments after the transfusion of G-CSF–mobilized granulocyte components and clinical outcomes after PBSC transplantation.