Allogeneic bone marrow transplantation (BMT) is a common treatment of hematologic malignancies. Recurrence of the underlying malignancy is a major cause of treatment failure. Donor-derived cytotoxic T lymphocytes (CTLs) specific for patients’ minor histocompatibility antigens (mHags) play an important role in both graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) reactivities. mHags HA-1 and HA-2 induce HLA-A*0201-restricted CTLs in vivo and are exclusively expressed on hematopoietic cells, including leukemic cells and leukemic precursors, but not on fibroblasts, keratinocytes, or liver cells. The chemical nature of the mHags HA-1 and HA-2 is known. We investigated the feasibility of ex vivo generation of mHag HA-1– and HA-2–specific CTLs from unprimed mHag HA-1– and/or HA-2–negative healthy blood donors. HA-1 and HA-2 synthetic peptide-pulsed dendritic cells (DCs) were used as antigen-presenting cells (APC) to stimulate autologous unprimed CD8+ T cells. The ex vivo–generated HA-1– and HA-2–specific CTLs efficiently lyse leukemic cells derived from acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL) patients. No lytic reactivity was detected against nonhematopoietic cells. Sufficient numbers of the CTLs can be obtained for the adoptive immunotherapy purposes. In conclusion, we present a feasible, novel therapy for the treatment for relapsed leukemia after BMT with a low risk of GVHD.

Introduction In general SARS-CoV-2-infection during pregnancy is not considered to be an increased risk for severe maternal outcomes, but has been associated with an increased risk for fetal distress. So far, there is no direct evidence of intrauterine vertical transmission and the mechanisms leading to the adverse outcomes are not well understood Results An asymptomatic pregnant woman with preterm fetal distress during the COVID19 pandemic was included. We obtained multiple maternal, placental and neonatal swabs, which showed a median viral load in maternal blood, urine, oropharynx, fornix posterior over a period of 6 days was 5.0 log copies /mL. The maternal side of the placenta had a viral load of 4.42 log copies /mL, while the fetal side had 7.15 log copies /mL. Maternal breast milk, feces and all neonatal samples tested negative. Serology of immunoglobulins against SARS-CoV-2 was tested positive in maternal blood, but negative in umbilical cord and neonatal blood. Pathological examination of the placenta included immunohistochemical investigation against SARS-CoV-2 antigen expression in combination with SARS-CoV-2 RNA in situ hybridization and transmission electron microscopy. It showed the presence of SARS-CoV-2 particles with generalized inflammation characterized by histiocytic intervillositis with diffuse perivillous fibrin depositions with damage to the syncytiotrophoblasts. Discussion Placental infection by SARS-CoV-2 lead to fibrin depositions hampering fetal-maternal gas exchange most likely resulted in fetal distress necessitating a premature emergency caesarean section. Postpartum, the neonate showed a clinical presentation resembling a pediatric inflammatory multisystem syndrome including coronary artery ectasia, most likely associated with SARS-CoV-2 (PIMS-TS) for which admittance and care on the Neonatal Intensive Care unit (NICU) was required, despite being negative for SARS-CoV-2. This highlights the need for awareness of adverse fetal and neonatal outcomes during the current COVID-19 pandemic, especially considering that the majority of pregnant women appear asymptomatic.

Allogeneic bone marrow transplantation (BMT) is a common treatment of hematologic malignancies. Recurrence of the underlying malignancy is a major cause of treatment failure. Donor-derived cytotoxic T lymphocytes (CTLs) specific for patients’ minor histocompatibility antigens (mHags) play an important role in both graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) reactivities. mHags HA-1 and HA-2 induce HLA-A*0201-restricted CTLs in vivo and are exclusively expressed on hematopoietic cells, including leukemic cells and leukemic precursors, but not on fibroblasts, keratinocytes, or liver cells. The chemical nature of the mHags HA-1 and HA-2 is known. We investigated the feasibility of ex vivo generation of mHag HA-1– and HA-2–specific CTLs from unprimed mHag HA-1– and/or HA-2–negative healthy blood donors. HA-1 and HA-2 synthetic peptide-pulsed dendritic cells (DCs) were used as antigen-presenting cells (APC) to stimulate autologous unprimed CD8+ T cells. The ex vivo–generated HA-1– and HA-2–specific CTLs efficiently lyse leukemic cells derived from acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL) patients. No lytic reactivity was detected against nonhematopoietic cells. Sufficient numbers of the CTLs can be obtained for the adoptive immunotherapy purposes. In conclusion, we present a feasible, novel therapy for the treatment for relapsed leukemia after BMT with a low risk of GVHD.

For vaccination strategies and adoptive immunotherapy purposes, immature dendritic cells (DC) can be generated from adherent monocytes using GM-CSF and IL-4. Presently, the only clinically applicable method to induce stable maturation of DC is the use of supernatants of activated monocytes (monocyte-conditioned medium (MCM)). MCM contains an undefined mixture of cytokines and is difficult to standardize. Here we report that stable maturation of DC can be simply induced by the addition of polyriboinosinic polyribocytidylic acid (poly(I:C)), a synthetic dsRNA clinically applied as an immunomodulator. Poly(I:C)-treated DC show a mature phenotype with high expression levels of HLA-DR, CD86, and the DC maturation marker CD83. This mature phenotype is retained for 48 h after cytokine withdrawal. In contrast to untreated DC, poly(I:C)-treated DC down-regulate pinocytosis, produce high levels of IL-12 and low levels of IL-10, induce strong T cell proliferation in a primary allo MLR, and effectively present peptide Ags to HLA class I-restricted CTL. In conclusion, we present a simple methodology for the preparation of clinically applicable mature DC.

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In this clinical pearl an ectopic human Dioctophyma renale infection in the abdominal cavity is reported for the first time. The patient presented with a gastric perforation and the release of an adult Dioctophyma renale through an abdominal drain and three co-infections (Plasmodium malariae, Strongyloides stercoralis and Mansonella perstans).

PurposeUveal Melanoma is a rare ocular malignancy; high‐risk monosomy 3 tumors often show an increased density of tumor‐infiltrating lymphocytes and macrophages. Histone deacetylases (HDACs) are a group of epigenetic modifiers, some of which are increased in monosomy 3 UM. We compared HDAC expression in Uveal Melanoma (UM) with the presence of infiltrating leukocytes. We furthermore determined whether expression was modifiable by interferon‐gamma.MethodsThe expression of nine HDACs and CD3E, CD8 and CD68 leukocyte markers was determined using an Illumina HT12V4 array in 64 primary UM. In addition, HDAC and infiltrate data were obtained from the TCGA for 80 cases. Four UM cell lines were treated with two doses of IFNɤ (50 IU, 200 IU), for 48 hrs. Quantitative PCR (qPCR) was used for mRNA measurement of HDAC expression in‐vitro.ResultsHDACs 1, 3, 7, and 8 were positively associated with CD3E, CD8A and CD68 leukocyte markers (P ≤ 0.05). Analysis from the TCGA similarly showed that HDACs 1, 3, and 8 were positively correlated with the presence of CD3E and CD8A.When looking at the possible effect of IFNɤ on four UM cell lines (OMM1, OMM2.5, MP38 and Mp46) we found that (in contrast to HLA‐A and HLA‐B mRNA expression which was induced in all four cell lines), HDACs 1, 4, 5, 7, and 8 were induced in two out of four UM cell lines (OMM2.5 and MP38).ConclusionsAs HDACs were previously shown to be upregulated in high‐risk monosomy 3 UM tumors, we wondered whether they are associated with the presence of tumor‐infiltrated lymphocytes and macrophages. Our findings indicate that several HDACs show positive correlation with tumor‐infiltrating lymphocytes and macrophages. As these HDACs were sensitive to induction, there may be a role for the infiltrating leukocytes in the upregulation of HDACs in Uveal melanoma.

Refractory stage M neuroblastoma (NB) is associated with a poor prognosis and a progressive course of disease. Here, we describe a unique group of patients with a discrepant clinical course. Seven histologically confirmed ganglioneuroblastoma (GNB) (n=6) and differentiating NB (n=1) patients were identified who were diagnosed with stage M disease based on iodine-123-metaiodobenzylguanidine avid bone metastases. Six patients started on high-risk treatment, without tumor response (stable disease). Treatment was discontinued before the start of consolidation treatment because of refractory response in all patients. Unexpectedly, after cessation of treatment no progression of disease occurred. In 2 patients, the primary tumors expanded (>25%) very slowly during 1.5 and 3 years, and remained stable thereafter. Metabolically, a slow decrease of urinary homovanillic acid and vanillylmandelic acid levels and iodine-123-metaiodobenzylguanidine avidity was observed. All patients are alive with presence of metastatic disease after a median follow-up of 17 years (range: 6.7 to 27 y). Interestingly, at diagnosis, 6 patients were asymptomatic, 6 patients had GNB morphology, and 5 patients had meningeal metastases. These are all features seen in only a small minority of stage M patients. This GNB entity illustrates the clinical heterogeneity of neuroblastic tumors and can be used to further study the developmental origin of different NB subtypes.