No abstract

Toxoplasmosis is a rare and possibly underestimated complication following hematopoietic stem cell transplantation (HSCT) associated with a high mortality rate, although the incidence of toxoplasmosis after HSCT in Japan has not been established. We retrospectively studied patients with toxoplasmosis after HSCT, and identified five patients who had been diagnosed with an acute exacerbation of toxoplasmosis among 279 HSCT recipients at our institution between 1998 and 2011, representing an incidence of 1.8 %. Among 87 autologous HSCT recipients, one definite case was diagnosed. The serological test for Toxoplasma gondii before HSCT was positive in 18 of 192 allogeneic HSCT recipients. Of the 18 seropositive patients, three had definite infections, and one had possible infection. All four definite cases were diagnosed at autopsy. In the definite cases, three allogeneic HSCT recipients had disseminated or pulmonary toxoplasmosis and one autologous HSCT recipient had toxoplasmic encephalitis, although toxoplasmosis was not suspected at the premortem examination due to non-specific clinical and radiological manifestations. Thus, acute exacerbation of toxoplasmosis should be suspected in recipients after HSCT. Early diagnosis and treatment for toxoplasmosis would certainly contribute to a decrease in mortality after HSCT.

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening disease of severe hyperinflammation caused by uncontrolled proliferation of activated lymphocytes and macrophages that secrete high amounts of inflammatory cytokines. HLH occurring after SCT is difficult to diagnose. It is characterized by severe clinical manifestations and high mortality. Despite current therapeutic approaches, outcomes remain poor. We analyzed the incidence and risk factors of HLH after SCT and the response to treatment and prognosis of 554 patients with HLH after SCT. The cumulative incidence of HLH after SCT was 4.3% (24/554). Use of etoposide in the conditioning regimen was only factor that reduced HLH after SCT (P ¼ 0.027). All patients who received autologous transplantation were successfully treated. Patients with liver dysfunction (for example, high total bilirubin level, prolonged prothrombin time and high level of fibrinogen degradation products) had a poor response to treatment for HLH. Physicians should be cautious of HLH, while not using etoposide for conditioning regimen.

Graft failure (GF) remains a major problem in cord blood transplantation (CBT). In 36 adult patients undergoing CBT at our hospital between July 2003 and December 2009, six patients developed GF (primary, n = 5; secondary, n = 1). All six patients underwent second stem cell transplantation (SCT). Three patients had acute myeloid leukemia, one had acute lymphoblastic leukemia, one had chronic myeloid leukemia, and one had aplastic anemia. Five patients were complicated with sepsis before the second SCT. The median elapsed time from first CBT to the diagnosis of primary GF was 27 days. Secondary GF was diagnosed on day 567. The median elapsed time from primary GF to second SCT was 9 days. In the patient with secondary GF, the elapsed time was 35 days. Cord blood grafts were used in 5 patients and a matched sibling donor in one patient. All 6 patients underwent second transplantation following a modified '1-day'-based preparative regimen consisting of fludarabine (30 mg/m(2), 1 day, n = 2; 2 days, n = 1; 3 days, n = 3), cyclophosphamide (2 g/m(2)), and total body irradiation (2 Gy). All patients achieved neutrophil engraftment, and the median elapsed time from second SCT to engraftment was 35 days. Four patients remain alive between 5 and 38 months after second SCT. '1-day'-based short-term conditioning may be a promising salvage regimen.

The activated partial thromboplastin time (APTT) assay is a basic hemostatic assay based on the time it takes for clots to form in plasma samples after the addition of calcium chloride. It is used to screen for various coagulation disorders. Several previous reports have suggested that magnesium (Mg) might contribute to coagulation reactions by binding to specific coagulation proteins. We investigated the effects of Mg on the APTT. In healthy controls, the APTT was significantly prolonged in proportion to the increase in the concentration of magnesium chloride in the range from 2.1 to 16.7 mmol/L. Among eight samples from patients with various disorders that exhibited prolonged APTT, two samples demonstrated shorter APTT when Mg was added, both of which were from patients that were positive for lupus anticoagulant. When we examined 206 clinical APTT samples, we found that Mg shortened the APTT of two samples. These two samples were also from lupus anticoagulant-positive patients (p-value: <0.003). Our findings regarding the unique effects of exogenous Mg on the APTT of lupus anticoagulant-positive patients might shed light on the role of Mg in APTT assays and lead to the development of a novel screening method for lupus anticoagulant.