Successful management of fetal hemolytic disease due to strong anti-Rh17 with plasma exchange and intrauterine transfusion in a woman with the D-- phenotype.

The rare blood phenotype D-- is characterized by the absence of RhCcEe antigens. Women with this blood type who have experienced previous pregnancies may produce anti-Rh17 antibodies, which may cause severe fetal hemolytic anemia or fetal death in subsequent pregnancies. We report successful management of a pregnancy associated with fetal hemolytic disease owing to high titers of anti-Rh17 (1:4096) in a woman with a history of a pregnancy with fetal hydrops and intrauterine fetal death. During her second pregnancy, she received two sets of plasma exchange (PE) per week from weeks 12 till 20. Intrauterine transfusions (IUTs) were performed at 26, 27, 29, and 31 weeks. A male infant was born at 32 weeks and 4 days by normal vaginal delivery, with a birth weight of 1916 g (+ 0.16 SD). He received an exchange transfusion on day 0, immunoglobulin (intravenous immunoglobulin: 1 g/kg) on days 0 and 1, and photo therapy from days 0 to 6. He showed normal development without neurological abnormality and was discharged from the hospital on day 36. We successfully prevented complications caused by the presence of anti-Rh17 antibodies in the mother during pregnancy. The IUT and maternal PE may have promoted this favorable outcome.

Distinct effects of daratumumab on indirect and direct antiglobulin tests: a new method employing 0.01 mol/L dithiothreitol for negating the daratumumab interference with preserving K antigenicity (Osaka method).

BACKGROUND: There is an increasing demand for daratumumab (DARA), an immunoglobulin (Ig)G1κ monoclonal antibody (MoAb) that recognizes CD38, to manage relapsed or refractory multiple myeloma (MM) patients. However, DARA leads to positive and panreactive agglutination reactions in indirect antiglobulin tests (IATs) in vitro (the DARA interference). In addition, effects of DARA on red blood cells (RBCs) in vivo remains elusive. STUDY DESIGN AND METHODS: To develop a new method to negate the DARA interference, the effects of various concentrations of dithiothreitol (DTT) on RBC CD38 and Kell antigenicity in combination with an automatic blood cell washing centrifuge were compared with the AABB standard procedure in parallel. Moreover, direct antiglobulin tests (DATs) for RBCs in DARA-treated MM patients were examined. RESULTS: A quantity of 0.01 mol/L DTT as well as the AABB procedure (equivalent to 0.15 mol/L DTT in our procedure) markedly reduced the reactivity of phycoerythrin-mouse anti-CD38 MoAb and DARA with RBCs. In sharp contrast to the AABB procedure, 0.01 mol/L DTT partially preserved K antigenicity and allowed the determination of phenotype of K antigen even in the presence of the DARA interference. In contrast, DAT for RBCs obtained from MM patients showed a weak positive or negative reaction. Immunoblotting further indicated that DARA induced loss of CD38 in vivo. CONCLUSION: A simple and reliable method to negate the DARA interference with partially preserving Kell antigenicity is proposed (Osaka method). CD38 antigenicity is susceptible to 0.01 mol/L DTT treatment even in the presence of DARA. Our data also demonstrate distinct effects of DARA on IAT in vitro and DAT in vivo.

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.

Clinical significance of IPF% or RP% measurement in distinguishing primary immune thrombocytopenia from aplastic thrombocytopenic disorders.

The diagnosis of primary immune thrombocytopenia (ITP) is based on differential diagnosis. Although the measurement of percentages of reticulated platelets (RP%) by flow cytometry is useful as a supportive diagnostic test, this method is nonetheless a time-consuming, laboratory-based assay. To identify alternative assays that are useful in daily practice, we compared three methods in parallel, IPF% measured by XE-2100 [IPF% (XE), Sysmex Corp.], IPF% measured by new XN-1000 [IPF% (XN)], and RP%. We examined 47 patients with primary ITP, 28 patients with aplastic thrombocytopenia (18 aplastic anemia and 10 chemotherapy-induced thrombocytopenia) and 80 healthy controls. In a selected experiment, we examined 16 patients with paroxysmal nocturnal hemoglobinuria (PNH) to examine the effect of hemolysis. As compared with IPF% (XE), IPF% (XN) showed better within-run reproducibility. The sensitivity and specificity for the diagnosis of ITP were 83.0 and 75.0 % for IPF% (XE), 85.1 and 89.3 % for IPF% (XN), and 93.6 and 89.3 % for RP%, respectively. Examination of PNH patients revealed that hemolysis and/or red blood cell fragments interfered with IPF% (XE) values, but not with IFP % (XN) values. Our results suggest that IPF% measured by XN-1000 may be of comparable value with RP% as a supportive diagnostic test for ITP.

A case of neonatal alloimmune thrombocytopenia in the presence of both anti-HPA-4b and anti-HPA-5b antibody: clinical and serological analysis of the subsequent pregnancy.

Neonatal alloimmune thrombocytopenia (NAIT) is induced by maternal alloantibodies raised against fetal platelet antigens inherited from the paternal parent. In contrast to Caucasians, in Asians, predominantly in Japanese, most frequently detected antibodies in NAIT are anti-HPA-4b and anti-HPA-5b. In some NAIT cases multiple alloantibodies are detected. In such cases it is very difficult to determine which antibody is the dominant antibody in NAIT. In this case report, we describe a NAIT case (first sibling) with severe thrombocytopenia and cephalhematoma in the presence of both anti-HPA-4b and anti-HPA-5b antibodies in the maternal serum. We carefully examined titers of anti-HPA antibodies during the subsequent pregnancy with HPA-4b-positive and HPA-5b-negative fetus determined by amniocentesis at gestational week 16. We administered IVIG (1 g/kg/w) to the mother from gestational week 32 to 35. The mother subsequently delivered a second sibling with normal platelet count by cesarean section. Although we could not completely rule out the involvement of anti-HPA-4b, our findings suggested that anti-HPA-5b was implicated in the NAIT in the first sibling.