Satoru Hayashi

Diagnostic Value of Tests for Reticulated Platelets, Plasma Glycocalicin, and Thrombopoietin Levels for Discriminating Between Hyperdestructive and Hypoplastic Thrombocytopenia

We measured reticulated platelets (RPs) and plasma glycocalicin (GC) and thrombopoietin (TPO) levels simultaneously in 107 thrombocytopenic patients to clarify the diagnostic value of these tests for discriminating hyperdestructive from hypoplastic thrombocytopenia. The percentage of RPs and GC index (plasma GC level normalized for the individual platelet count) were markedly elevated in patients with idiopathic thrombocytopenic purpura (ITP) but normal or slightly elevated in patients with aplastic anemia (AA) or chemotherapy-induced thrombocytopenia (ChemoT). For RP percentage for diagnosing hyperdestructive thrombocytopenia the sensitivity and specificity were excellent but were lower for the GC index. Absolute RP counts and plasma GC levels were markedly decreased and plasma TPO levels markedly elevated in patients with AA or ChemoT, but absolute RP counts and plasma GC levels were moderately decreased and plasma TPO levels only slightly elevated in patients with ITP. The sensitivity and specificity of plasma TPO levels for diagnosing hypoplastic thrombocytopenia were excellent. Using the RP percentage and plasma TPO levels in combination improved specificities. Simultaneous measurement of RP percentage and plasma TPO level may help discriminate thrombocytopenia of unknown cause in routine hematologic practice.

Elevated platelet-associated IgG in SLE patients due to anti-platelet autoantibody: differentiation between autoantibodies and immune complexes by ether elution

Summary The level of platelet‐associated IgG (PAIgG) is reported to be elevated in patients with systemic lupus erythematosus (SLE). However. the nature of PAIgG is unclear. We have investigated whether the PAIgG of SLE consists of anti‐platelet autoantibodies or immune complexes (IC). The PAIgG values measured by flow cytonietry were elevated in 11/25 patients with SLE. 3/6 SLE patients with thrombocytopenia had a high level of PAIgG (the mean fluorescence intensity >10). We used an ether elution technique to determine whether elevated PAIgG consists of anti‐platelet antibodies or IC. Preliminary experiments showed that the eluates prepared from platelets sensitized with anti‐HPA‐4a antibody reacted with normal platelets. while the eluates prepared from platelets sensitized with heat‐aggregated IgG or model IC failed to react with normal platelets. These results indicate that the reactivity of eluates can distinguish between platelet‐bound antibody and IC. We applied this technique to analysis of the PAIgG of SLE platelets. The eluates from SLE platelets (the mean fluorescence intensity > 10) reacted with normal platelets. indicating that the PAIgG of SLE platelets has the nature of anti‐platelet autoantibodies. Furthermore, we investigated the target antigens which bind PAIgGs of SLE, using the direct immunoprecipitation procedure and modified antigen capture ELISA (MACE). Both methods identified GPIIb/IIIa as the target antigens. We conclude that the ether elution technique can distinguish between anti‐platelet antibodies and TC. and that the PAIgGs of SLE with a high PAIgG value and thrombocytopenia have the nature of anti‐platelet autoantibodies.

Immature platelet fraction (IPF) as a predictive value for thrombopoietic recovery after allogeneic stem cell transplantation

We consecutively examined the utility of measurements of percentage of immature platelet fraction (IPF%) and absolute IPF number (A-IPF) in predicting thrombopoietic recovery in 15 adult patients who underwent allogeneic hematopoietic stem cell transplantation (allo-SCT). Four patients were excluded from the evaluation due to insufficient data. Platelet count and IPF were measured by Sysmex XN-1000 (XN), a newer generation analyzer. First, we confirmed that platelet count measured by XN was more accurate than by XE-2100 (XE). IPF measurement was effective to predict the recovery in 7 of the 11 patients examined. Moreover, IPF measurement, especially IPF% measurement, suggested accelerated platelet turnover in two patients who failed to achieve platelet recovery by day 60. In addition to IPF%, A-IPF showed a complementary role on the prediction of thrombopoietic recovery. The increase in IPF% was only transient, while A-IPF values showed lasting increase during platelet recovery. In two patients (cases 6 and 7) an increase in A-IPF, but not in IPF%, was observed during platelet recovery. Our data suggest that IPF% and A-IPF measured by XN are useful for the prediction of thrombopoietic recovery and the assessment of pathogenesis of thrombocytopenia in patients after allo-SCT.

Report on ABO-Incompatible Transfusions in 12 University Hospitals in Kinki Districts.

We investigated the incidence and the causes of ABO-incompatible transfusion in 12 university hospitals in the Kinki district during the 5-year period from 1993 through 1997. Over 5 years, 648, 553 units of red cell components (RBC) and 2, 545, 880 units of fresh frozen plasma (FFP) or platelet concentrate (PC) were transfused, and a total of 26 ABO-incompatible transfusions occurred. Incompatible RBC were transfused to 17 patients and FFP or PC were transfused to the remaining 9 patients. In cases of RBC transfusion, half of errors (8 cases) were due to misidentification of blood units and the other half of errors (8 cases) were due to incorrect typing. Twenty of 26 errors occurred during night shifts and the majority of errors occurred in the ward (17 cases) or operating room (5 cases). Various measures were taken to prevent ABO-incompatible transfusion at the participating universities. We conclude that continued data collection and analysis are necessary to prevent ABO-incompatible transfusion.

A case of immune hemolytic anemia due to "auto" anti-A1 antibody induced by group O homograft in renal transplantation recipient.

A case of severe auto-immune hemolytic anemia after a living, ABO-incompatible renal transplantation is reported.The recipient, a 34 years old man, blood group A1, Rh0 (D) positive receieved a renal transplant from father whose blood group O, Rh0(D) positive donor. Cyclosporine, prednisolone and mizoribine were used for immunosuppresion.The recipient devloped severe immune hemolytic anemia within 2 weeks of renal transplantation. The recipients serum contained anti-A1 IgG autoantibody and anti-B IgG antibody on day 18 post-transplantation. The IgG subclass of these antibodies was IgG3.

ELISA for detection of red cell antibodies using red cell ghosts coated plates. The detection of Rh and other antibodies.

An ELISA using micro-plates coated with red cell ghosts was developed for analysis of red cell antibodies.Antibodies against MNSs, Kell, Duffy and Kidd antigens were detected using this ELISA. Rh antibodies in patients sera could be also detected by this assay, but the elution technique was needed when the titer of antibody was low.We considered that this assay was quantitative, objective and sensitive compared with indirect antiglobulin test, and easy to perform compared with ELISA of tube method using red cell suspensions.