Dendritic cell vaccination as postremission treatment to prevent or delay relapse in acute myeloid leukemia.

Relapse is a major problem in acute myeloid leukemia (AML) and adversely affects survival. In this phase 2 study, we investigated the effect of vaccination with dendritic cells (DCs) electroporated with Wilms' tumor 1 (WT1) messenger RNA (mRNA) as postremission treatment in 30 patients with AML at very high risk of relapse. There was a demonstrable antileukemic response in 13 patients. Nine patients achieved molecular remission as demonstrated by normalization of WT1 transcript levels, 5 of which were sustained after a median follow-up of 109.4 months. Disease stabilization was achieved in 4 other patients. Five-year overall survival (OS) was higher in responders than in nonresponders (53.8% vs 25.0%; P = .01). In patients receiving DCs in first complete remission (CR1), there was a vaccine-induced relapse reduction rate of 25%, and 5-year relapse-free survival was higher in responders than in nonresponders (50% vs 7.7%; P < .0001). In patients age ≤65 and >65 years who received DCs in CR1, 5-year OS was 69.2% and 30.8% respectively, as compared with 51.7% and 18% in the Swedish Acute Leukemia Registry. Long-term clinical response was correlated with increased circulating frequencies of polyepitope WT1-specific CD8+ T cells. Long-term OS was correlated with interferon-γ+ and tumor necrosis factor-α+ WT1-specific responses in delayed-type hypersensitivity-infiltrating CD8+ T lymphocytes. In conclusion, vaccination of patients with AML with WT1 mRNA-electroporated DCs can be an effective strategy to prevent or delay relapse after standard chemotherapy, translating into improved OS rates, which are correlated with the induction of WT1-specific CD8+ T-cell response. This trial was registered at www.clinicaltrials.gov as #NCT00965224.

EBV-associated hemophagocytic lymphohistiocytosis complicated by severe coagulation disorders and opportunistic infections: case report of a survivor.

The possibility of hemophagocytic lymphohistiocytosis should always be kept in mind when examining/treating a patient with fever of unknown origin and sepsis-like symptoms. Early diagnosis leading to prompt initiation of immunosuppressive therapy as well as aggressive supportive care, including correction of coagulation abnormalities and treatment of opportunistic infections, can decrease mortality.

Factor V inhibitor: case report.

Acquired inhibitors to coagulation factors are rare, certainly those directed against factor V. A total of around 150 cases have so far been reported, of which the greater part was due to bovine thrombin exposure. We report the case of a patient who developed a factor V inhibitor during a postoperative period. This report describes possible aetiologies, varying clinical conditions and treatment possibilities as described in the literature. Furthermore, this case report is an example of the often unpredictable disease progression in a patient with existence of a factor V inhibitor.

Influence of frequent infectious exposures on general and varicella-zoster virus-specific immune responses in pediatricians.

Reexposure to viruses is assumed to strengthen humoral and cellular immunity via the secondary immune response. We studied the effects of frequent exposure to viral infectious challenges on immunity. Furthermore, we assessed whether repetitive exposures to varicella-zoster virus (VZV) elicited persistently high immune responses. Blood samples from 11 pediatricians and matched controls were assessed at 3 time points and 1 time point, respectively. Besides the assessment of general immunity by means of measuring T-cell subset percentages, antibody titers and gamma interferon (IFN-γ)/interleukin 2 (IL-2)-producing T-cell percentages against adenovirus type 5 (AdV-5), cytomegalovirus (CMV), tetanus toxin (TT), and VZV were determined. Pediatricians had lower levels of circulating CD4(+)-naive T cells and showed boosting of CD8(+) effector memory T cells. Although no effect on humoral immunity was seen, repetitive exposures to VZV induced persistently higher percentages of IFN-γ-positive T cells against all VZV antigens tested (VZV glycoprotein E [gE], VZV intermediate-early protein 62 [IE62], and VZV IE63) than in controls. T cells directed against latency-associated VZV IE63 benefitted the most from natural exogenous boosting. Although no differences in cellular or humoral immunity were found between the pediatricians and controls for AdV-5 or TT, we did find larger immune responses against CMV antigens in pediatricians. Despite the high infectious burden, we detected a robust and diverse immune system in pediatricians. Repetitive exposures to VZV have been shown to induce a stable increased level of VZV-specific cellular but not humoral immunity. Based on our observations, VZV IE63 can be considered a candidate for a zoster vaccine.

Sampling site matters when counting lymphocyte subpopulations.

Clinical and scientific work routinely relies on antecubital venipunctures for hematological, immunological or other analyses on blood. This study tested the hypothesis that antecubital veins can be considered to be a good proxy for other sampling sites. Using a hematocytometer and a flow cytometer, we analyzed the cell counts from samples coming from the radial artery, the dorsal hand veins and the antecubital veins from 18 volunteers. Most surprisingly, we identified the greatest difference not to exist between arterial and venous circulation, but between the distal (radial artery & dorsal hand veins) and proximal (antecubital veins) sampling sites. Naïve T cells had a higher cell count distally compared to proximally and the reverse was true for effector memory T cells. Despite these differences there were high correlations between the different sampling sites, which partially supports our initial hypothesis. Our findings are crucial for the future design and interpretation of immunological research, and for clinical practice. Furthermore, our results suggest a role for interval lymph nodes in the trafficking of lymphocytes.

Reference intervals for a complete blood count determined on different automated haematology analysers: Abx Pentra 120 Retic, Coulter Gen-S, Sysmex SE 9500, Abbott Cell Dyn 4000 and Bayer Advia 120.

We processed 317 samples from healthy adult volunteers for a complete blood count, including leukocyte differentials and reticulocyte parameters, through five new-generation haematology analysers: Abx Pentra 120 Retic, Coulter Gen-S, Sysmex SE 9500, Abbott Cell Dyn 4000 and Bayer Advia 120. From these data non-parametric 2.5-97.5 percentile reference intervals were calculated for all parameters on all analysers. Some differences were found compared with previously reported reference intervals. Reference intervals for platelet parameters and reticulocytes agreed with these usually accepted. For red blood cell parameters, including haemoglobin and haematocrit, and white blood cell count, including absolute white blood cell differentials, our calculated reference intervals were in agreement with less frequently cited earlier reports, but were lower compared to the usually accepted reference intervals.