High levels of serum glycans monovalent IgG immune complexes detected by dissociative ELISA in experimental visceral leishmaniasis

Visceral leishmaniasis (VL) is epidemic in Brazil with an increasing incidence of human cases and canine reservoirs, with host hypergammaglobulinemia. Conventional enzyme-linked immunosorbent assay (cELISA) based on several parasitic antigens is the main method for diagnosis and indication of treatment. Dissociative ELISA (dELISA) uses acidic treatment to free immunoglobulin G (IgG) from immune complexes, and its use revealed a significant positive fraction of suspected cases with negative serology. Looking for small molecules or haptens that block IgG antibodies, we purified by molecular exclusion chromatography, 1000–3000 MW molecules from promastigote soluble extract, mostly oligosaccharides comprising 6–13 sugar residues using MALDI-TOF analysis. Glycan-BSA complex (GBC) was constructed by conjugating promastigote glycans to BSA molecules, allowing their use in the solid support in cELISA or dELISA. Sera from experimentally infected hamsters showed higher levels of blocked monomeric IgG during infection, mostly against GBC, which was also present in lower concentrations in the promastigote soluble extract dELISA. Those data show that most of the specific monomeric IgG in serum are blocked by haptens composed by glycans produced by the parasite, better detected in the high dilution of sera in the dELISA assays. dELISA is a useful technique for detecting blocked monomeric antibodies that could have difficult clearance from blood, which could result in hypergammaglobulinemia.     

Mis-splicing in breast cancer: identification of pathogenic BRCA2 variants by systematic minigene assays

This commentary addresses the issue of the classification of sarcomas in the article written by Watson and colleagues published recently in this journal. The article delves into the molecular characterization and distinct phenotypes of some recently described entities (e.g. BCOR-rearranged sarcomas, CIC-fused sarcomas) and describes new groups with common characteristics. This commentary focuses on several questions raised in the article, such as what makes a group of sarcomas become a clinical entity, which should be the main driver of sarcoma classification, how the classification of small round cell sarcomas is expected to evolve and how high-throughput techniques could be applied to sarcoma diagnosis in the short term. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Mandible strength and geometry in relation to bite force: a study in three caviomorph rodents

The monophyletic group Caviomorpha constitutes the most diverse rodent clade in terms of locomotion, ecology and diet. Caviomorph species show considerable variation in cranio‐mandibular morphology that has been linked to the differences in toughness of dietary items and other behaviors, such as chisel‐tooth digging. This work assesses the structural strength of the mandible of three caviomorph species that show remarkable differences in ecology, behavior and bite force: Chinchilla lanigera (a surface‐dwelling species), Octodon degus (a semi‐fossorial species) and Ctenomys talarum (a subterranean species). Finite element (FE) models of the mandibles are used to predict the stresses they withstand during incisor biting; the results are related to in vivo bite forces and interspecific variations in the mandibular geometries. The study concludes that the mandible of C. talarum is better able to withstand strong incisor bites. Its powerful adducting musculature is consistent with the notorious lateral expansion of the angular process and the masseteric crest, and the enhanced cortical bone thickness. Although it has a relatively low bite force, the mandible of O. degus also shows a good performance for mid‐to‐strong incisor biting, in contrast to that of C. lanigera, which exhibits, from a mechanical point of view, the worst performance. The mandibles of C. talarum and O. degus appear to be better suited to withstand stronger reaction forces from incisor biting, which is consistent with their closer phylogenetic affinity and shared digging behaviors. The contrast between the low in vivo bite force of C. lanigera and the relatively high estimations that result from the models suggests that its adductor musculature could play significant roles in functions other than incisor biting.     

Variable sources of Bk virus in renal allograft recipients

BK virus is the causative agent of polyomavirus-associated nephropathy, a major cause of kidney transplant failure affecting 1%-10% of recipients. Previous studies that investigated the viral source on the kidney recipient pointed that the donor is implicated in the origin of human polyomavirus BK (BKPyV) infection in recipients, but giving the low genetic variability of BKPyV this subject is still controversial. The aim of this study was to determine if BKPyV replicating in kidney recipients after transplantation is always originated from the donor. Urine and blood samples from 68 pairs of living donors and kidney recipients who underwent renal transplantation from August 2010-September 2011 were screened for BKPyV by real time polymerase chain reaction. Only three recipients presented viremia. When both donors and recipients were BKPyV positive, a larger fragment of VP1 region was obtained and sequenced to determine the level of similarity between them. A phylogenetic tree was built for the 12 pairs of sequences obtained from urine and high level of similarity among all sequences was observed, indicating that homology inferences for donor and recipient viruses must be cautiously interpreted. However, a close inspection on the donor-recipient pairs sequences revealed that 3 of 12 pairs presented considerably different viruses and 4 of 12 presented mixed infection, indicating that the source of BKPyV infection is not exclusively derived from the donor. We report that about 60% of the renal recipients shed BKPyV genetically distinct from the donor, confronting the accepted concept that the donor is the main source of recipients’ infection.     

Spontaneously-resolving episodes of cytomegalovirus DNAemia in allogeneic hematopoietic stem cell transplant recipients: Virological features and clinical outcomes

It has been reported that low-plasma cytomegalovirus (CMV) DNA loads are associated with an increased risk of overall mortality in allogeneic hematopoietic stem cell transplantation (allo-HSCT). Utilizing a conservative strategy for initiation of preemptive antiviral therapy (>1500 IU/mL), we characterized the virological features of spontaneously-resolving episodes of CMV DNAemia and assessed their impact on mortality through the first year after transplantation. We reviewed the CMV DNA polymerase chain reaction results and clinical charts of 230 consecutive adult patients who underwent T-cell replete allo-HSCT at our center. A total of 280 episodes of CMV DNAemia were registered in 164 patients, of which 144 episodes cleared spontaneously. Clearance of CMV DNAemia was significantly delayed in initial and recurrent self-resolving episodes featuring CMV DNA peak loads > 250 IU/mL compared with those displaying lower values. All-cause mortality in patients with self-resolving episodes of CMV DNAemia was comparable (P = 0.7) to that in patients with no CMV DNAemia and was not related to the CMV DNA peak load (≥250 IU/mL vs <250 IU/mL) (P = 0.6). In summary, in our setting, the magnitude of the CMV DNA peak load reached during self-resolving episodes of CMV DNAemia correlated directly with duration of episodes, but had no apparent impact on all-cause mortality taking patients with no documented CMV DNAemia as a reference.     

Identification of human parvovirus B19 among measles and rubella suspected patients from Cuba

Between September 2014 and December 2015, 298 sera from rash and fever patients from all over Cuba were investigated for specific IgM antibodies against measles, rubella, dengue, human parvovirus B19 (B19V) and human herpesvirus 6 (HHV6) using a commercial enzyme-linked immunosorbent assay kits. B19V IgM positive and equivocal samples were investigated by a polymerase chain reaction and genotyping. No measles, rubella or dengue cases were detected. HHV6-IgM antibodies were confirmed in 5.7% and B19V-IgM antibodies in 10.7% of the patients. A total of 31.3% of the B19V cases were between 5 and 9 years old and 34.4% were 20 years and older. The only B19V sequence obtained belonged to genotype 1a. Diagnosis was established for only 16% of the rash and fever patients, suggesting that other diseases such as Zika or Chikungunya may play a role.