Zebrafish type I collagen mutants faithfully recapitulate human type I collagenopathies

The type I collagenopathies are a group of heterogeneous connective tissue disorders, that are caused by mutations in the genes encoding type I collagen and include specific forms of osteogenesis imperfecta (OI) and the Ehlers-Danlos syndrome (EDS). These disorders present with a broad disease spectrum and large clinical variability of which the underlying genetic basis is still poorly understood. In this study, we systematically analyzed skeletal phenotypes in a large set of zebrafish, with diverse mutations in the genes encoding type I collagen, representing different genetic forms of human OI, and a zebrafish model resembling human EDS, which harbors a number of soft connective tissues defects, typical of EDS. Furthermore, we provide insight into how zebrafish and human type I collagen are compositionally and functionally related, which is relevant in the interpretation of human type I collagen-related disease models. Our studies reveal a high degree of intergenotype variability in phenotypic expressivity that closely correlates with associated OI severity. Furthermore, we demonstrate the potential for select mutations to give rise to phenotypic variability, mirroring the clinical variability associated with human disease pathology. Therefore, our work suggests the future potential for zebrafish to aid in identifying unknown genetic modifiers and mechanisms underlying the phenotypic variability in OI and related disorders. This will improve diagnostic strategies and enable the discovery of new targetable pathways for pharmacological intervention

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 impacts survival. In this phase II study, we investigated the effect of vaccination with dendritic cells (DCs) electroporated with Wilms’ tumor 1 (WT1) mRNA as post-remission treatment in 30 AML patients at very high risk of relapse. There was a demonstrable anti-leukemic response in 13 patients. Nine patients achieved molecular remission as demonstrated by normalization of WT1 transcript levels, 5 of which are 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 non-responders (53.8% vs. 25.0%; P=0.01). In patients receiving DCs in first complete remission (CR1), there was a vaccine-induced relapse reduction rate of 25% and the 5-year relapse-free survival was higher in responders than in non-responders (50% vs. 7.7%; P65 years who received DCs in CR1, 5-year OS was 69.2% and 30.8% respectively, as compared to 51.7% and 18% in the Swedish Acute Leukemia Registry (SALR). Long-term clinical response was correlated with increased circulating frequencies of poly-epitope 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 AML patients 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

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

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

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

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

Comparisons between the lymphocyte subpopulation counts at different sampling sites.

<p>Lymphocyte subpopulation counts are shown for all comparisons with P<.10 for both the relative and absolute cell counts. The univariate T/W method shows the P value for the two-sided paired t-test ‘T’ (‘Ln’ when a natural logarithm was applied) or Wilcoxon paired-matched signed rank (‘W’) in case normality didn’t hold. The Bonferroni and Benjamini columns show the adjusted significance levels according to the method applied. Sensitivity for outliers was performed for the relative cell counts. The mixed column shows all comparisons with P<.10 assessed as contrasts within a multivariate analysis for the relative counts for the lymphocyte subpopulations using SAS 9.2. The mixed joint column shows the multivariate P value. See Materials & Methods for more information.</p><p>Results annotated with ‘*’ are considered significant for the method applied. <i>Sites</i> comparison between sampling sites; <i>ARD</i> average relative difference; <i>PLT</i> platelets; <i>NGC</i> neutrophils; <i>WBC</i> white blood cells; <i>RBC</i> red blood cells; <i>HCT</i> hematocrit; <i>RD</i> radial artery vs. dorsal hand veins; <i>RE</i> radial artery vs. antecubital veins; <i>DE</i> dorsal hand veins vs. antecubital veins.</p>a<p>After omission of outliers the P value from the paired t-test was 0.093 with ARD 6.7%. The multivariate analysis showed a P value of 0.014.</p>b<p>After omission of outliers the P value from the paired t-test was 0.11 with ARD 3.3%. The multivariate analysis showed a P value of 0.042.</p

Comparisons between the hematocytological counts at different sampling sites.

<p>Hematocytological counts are shown for all comparisons with P<.10 for both the raw and normalized cell counts. The univariate T/W method shows the P value for the two-sided paired t-test ‘T’ (‘Ln’ when a natural logarithm was applied) or Wilcoxon paired-matched signed rank (‘W’) in case normality didn’t hold. The Bonferroni and Benjamini columns show the adjusted significance levels according to the method applied. Sensitivity for outliers was investigated for the raw cell counts. See Materials & Methods for more information.</p><p>Results annotated with ‘*’ are considered significant for the method applied. <i>Sites</i> comparison between sampling sites; <i>ARD</i> average relative difference; <i>PLT</i> platelets; <i>MON</i> monocytes; <i>BAS</i> basophils; <i>NGC</i> neutrophils; <i>LEU</i> leukocytes; <i>RBC</i> red blood cells; <i>HCT</i> hematocrit; <i>RD</i> radial artery vs. dorsal hand veins; <i>RE</i> radial artery vs. antecubital veins; <i>DE</i> dorsal hand veins vs. antecubital veins; <i>NA</i> not applicable.</p>a<p>After omission of outliers the ARD for RE reduced to 3.4% and for DE to 3.7% with significances similar to before.</p