The value of crossmatch tests and panel tests as a screening tool to predict the outcome of platelet transfusion in a non-selected haematological population of patients.

BACKGROUND AND OBJECTIVES: Alloantibodies against platelets can be detected by using different laboratory tests. Most of these tests, which use panel cells or antigens as a target, perform poorly in non-selected haematological patients. In relation to these tests, a crossmatch test of transfused platelets and patient's serum may be viewed as the standard and may be superior in predicting donor platelet destruction by alloimmunization. MATERIALS AND METHODS: In 95 randomly selected thrombocytopenic patients with haematological malignancies, who were receiving leucodepleted blood products, 184 serum samples were studied in an in vitro crossmatch test by using the technique of the platelet immunofluorescence test (crossmatch-PIFT), in an in vivo crossmatch test detecting in vivo binding of immunoglobulins to transfused platelets according to the PIFT technique (in vivo-PIFT), in the indirect PIFT using five random donors as a target (panel-PIFT) and in an enzyme linked immunosorbent assay using immobilized human leucocyte antigens (HLAs) of 100 standardized donors (ELIHLA). The results of all these methods were related to the recovery at 1 and 16 h post-transfusion. RESULTS: The results of the crossmatch-PIFT were not associated with platelet recovery at 1 and 16 h after transfusion. Even in a subgroup of patients, in whom predefined clinical factors were excluded, no association with platelet recovery was found. The results of the crossmatch-PIFT correlated with those of the in vivo-PIFT (P = 0.02); however, 35 (19%) discrepant results were identified between these tests. The results of the crossmatch-PIFT were not related to the panel-PIFT (P = 0.25), but did relate to those of the ELIHLA (P = 0.02), still revealing 36 (20%) discrepant results. None of the in vivo-PIFT, the panel-PIFT or the ELIHLA was associated with platelet recovery after 1 h, whilst only a positive panel-PIFT was associated with poor platelet recovery at 16 h after transfusion (P = 0.03). CONCLUSIONS: In a population at low risk for alloimmunization, the correlation of test outcome and platelet recovery is poor. None of these crossmatch tests or screening tests was identified as superior to any other in this population.

Visual scoring versus histogram subtraction of in vivo binding of immunoglobulins against platelets after transfusion.

BACKGROUND: We developed a technique, in vivo binding of immunoglobulins in the platelet immunofluorescence test (IVBI-PIFT), that detects immunoglobulins bound in vivo to transfused platelets. The visually scored results of this technique, however, are susceptible to interobserver variation. We describe a more objective method to generate results in IVBI-PIFT. METHODS: We studied 201 samples in 120 patients with hematologic malignancies in the IVBI-PIFT. Histogram subtraction, i.e., fluorescence (anti-immunoglobulin G and fluorescein isothiocyanate) histogram before platelet transfusion subtracted from the histogram after platelet transfusion, was compared with visual scoring (pattern 1: no enhanced fluorescence before and after transfusion; pattern 2: enhanced fluorescence before and after platelet transfusion; pattern 3: enhanced fluorescence before transfusion; pattern 4: enhanced fluorescence after transfusion, interpreted as alloimmunization). After histogram subtraction, the number of remaining events (events post substraction, EPS) and the mean amount of fluorescence of these remaining events (mean channel post substraction, MCPS) were used and compared with the visual scoring and with platelet survival after transfusion. RESULTS: In 26 (13%) of the 201 samples studied in the IVBI-PIFT, fewer than three of five observers agreed on the visually scored pattern. In the 175 (87%) remaining samples, histogram subtraction showed a significant differentiation between pattern 4 and patterns 1 and 2 by using EPS, whereas patterns 4 and 3 were distinguished by using MCPS. The combination of EPS and MCPS differentiated best between pattern 4 and patterns 1, 2, and 3 (73% sensitivity, 96% specificity, 79% positive predictive value, and 95% negative predictive value). In contrast, the predictive value for platelet recovery after 1 and 16 h of pattern 4 from the visual scoring method and the results of histogram subtraction were poor. CONCLUSION: This objective method of histogram subtraction correlated well with the visual scoring method of IVBI-PIFT.

Two patients with acute thrombocytopenia following gold administration and five-year follow-up.

Thrombocytopenia is a well-known side effect following intramuscular gold therapy in patients with rheumatoid arthritis. Thrombocytopenia may occur at any time and it can be irreversible and sometimes fatal despite cytotoxic or immunosuppressive therapy. We describe two patients who presented with haemorrhagic diathesis on the day after the administration of aurothioglucose. The thrombocytopenia in these patients was caused by aurothioglucose-induced antibody-mediated platelet destruction. Both patients made an uneventful recovery and the platelet count returned to normal within several weeks without further treatment. Antibody-detecting tests were repeated five years later and could not demonstrate the presence of antibodies. Also after incubation with aurothioglucose no antibodies could be demonstrated.

Immune and nonimmune causes of low recovery from leukodepleted platelet transfusions: a prospective study.

Alloantibodies against HLA antigens can be reduced by applying leukodepletion to transfusions. Because the importance of immunological and nonimmunological causes of poor platelet transfusion results using leukodepleted transfusions is not clear, we conducted a prospective study in an unselected patient population receiving leukodepleted transfusions. In 97 patients with hematological malignancies, 181 random leukodepleted platelet transfusions were studied for immunological causes of poor platelet transfusion results by calculating the odds ratio of four different screening tests for a low platelet recovery. Nonimmune causes were also studied by calculating the odds ratio of the most prevalent nonimmune causes for a low platelet recovery. No single screening test showed an association with recovery after 1 and 16 h following a platelet transfusion. The combination of a positive enzyme-linked immunosorbent assay (ELISA) and platelet immunofluorescence test (PIFT) or a combination of a positive lymphocyte immunofluorescence test (LIFT) and PIFT, demonstrating an association with a low platelet recovery after 16 h, was present in 2% of all platelet transfusions. Of nonimmune causes, splenomegaly and storage time of platelets for more than 3 days were associated with low platelet recovery after 1 h and 16 h of being present in 29% and 47% of all platelet transfusions, respectively. Immunological causes account for a small proportion of poor platelet transfusion results compared to nonimmunological causes in a nonselected patient population receiving leukodepleted transfusions.

Chemotaxis of the peritoneal cells and the detection of a chemo-attractant in the effluent from peritoneal dialysis patients.

The migration of peritoneal cells from 25 continuous ambulatory peritoneal dialysis patients and eight healthy women undergoing laparoscopy were studied. Peritoneal cells of continuous ambulatory peritoneal dialysis patients migrated to commonly used chemoattractants, like N-formyl-methionyl-leucyl-phenyl-alanine-methyl- ester and casein, but they also migrated to high concentrations of recombinant interleukin-1 alpha and to endotoxin (lipopolysaccharide). In the peritoneal effluent from continuous ambulatory peritoneal dialysis patients a rather heat stable chemoattractant was found with a molecular weight of 40-200 kDa with an optimal activity at approximately 125 kDa. The chemoattractant is a protein and is not complement factor 5a or interleukin-1 and was only found in peritoneal effluent from continuous ambulatory peritoneal dialysis patients, but not in peritoneal fluid from healthy women undergoing laparoscopy. Therefore, peritoneal dialysis might induce the generation of a chemoattractant. The optimal chemotactic response of peritoneal cells from continuous ambulatory peritoneal dialysis patients to N-formyl-methionyl-leucyl-phenyl-alanine-methyl- ester in medium could be enhanced by replacing the medium by peritoneal effluent. So the chemotaxis of peritoneal cells to the factor in the peritoneal effluent is caused by another mechanism, which might involve different cell surface receptor populations, than the chemotactic response to N-formyl-methionyl-leucyl-phenyl-alanine-methyl-ester.

Peritoneal dialysis fluid induces change of mononuclear phagocyte proportions.

Peritoneal macrophages from uninfected continuous ambulatory peritoneal dialysis (CAPD) patients in general show two different, endogenous peroxidase activity (PA) patterns: exudate and negative. This suggests, in accordance with the animal model, that these macrophages are changed proportionately in CAPD patients. This chronic change may be caused by mechanical stimulation alone (massage) or the composition of the dialysis fluid used. Therefore in the rat model both physiological saline and commercial dialysis fluid were intraperitoneally (i.p.) administrated. Our results on the PA-pattern of peritoneal macrophages do indicate that a single i.p. administration of commercial dialysis fluid induced an acute exudate, especially when compared with the minor saline effect. These results are confirmed by the percentage of macrophages positive for a differentiation antigen recognized by the monoclonal antibody ED2. In addition the percentage of Fc-receptor positive peritoneal cells is more enhanced after i.p. injection of dialysis fluid when compared with the saline effect. These findings strongly suggest that the dialysis fluid used in peritoneal dialysis patients is the inducer of exudate peritoneal macrophages in these patients.