SARS-CoV-2 immunochromatographic IgM/IgG rapid test in pregnancy: A false friend?

BACKGROUND

An increasing body of evidence has revealed that SARS-CoV-2 infection in pregnant women could increase the risk of adverse maternal and fetal outcomes. Careful monitoring of pregnancies with COVID-19 and measures to prevent neonatal infection are warranted. Therefore, rapid antibody tests have been suggested as an efficient screening tool during pregnancy.

CASES

We analysed the clinical performance during pregnancy of a rapid, lateral-flow immunochromatographic assay for qualitative detection of SARS-CoV-2 IgG/IgM antibodies. We performed a universal screening including 169 patients during their last trimester of pregnancy. We present a series of 14 patients with positive SARS-CoV-2 immunochromatographic assay rapid test result. Immunochromatographic assay results were always confirmed by chemiluminescent microparticle immunoassays for quantitative detection of SARS-CoV-2 IgG and IgM+IgA antibodies as the gold standard. We observed a positive predictive value of 50% and a false positive rate of 50% in pregnant women, involving a significantly lower diagnostic performance than reported in non-pregnant patients.

DISCUSSION

Our data suggest that although immunochromatographic assay rapid tests may be a fast and profitable screening tool for SARS-CoV-2 infection, they may have a high false positive rate and low positive predictive value in pregnant women. Therefore, immunochromatographic assay for qualitative detection of SARS-CoV-2 IgG/IgM antibodies must be verified by other test in pregnant patients.

Detection of Short-Waved Spin Waves in Individual Microscopic Spin-Wave Waveguides Using the Inverse Spin Hall Effect

The miniaturization of complementary metal-oxide-semiconductor (CMOS) devices becomes increasingly difficult due to fundamental limitations and the increase of leakage currents. Large research efforts are devoted to find alternative concepts that allow for a larger data-density and lower power consumption than conventional semiconductor approaches. Spin waves have been identified as a potential technology that can complement and outperform CMOS in complex logic applications, profiting from the fact that these waves enable wave computing on the nanoscale. The practical application of spin waves, however, requires the demonstration of scalable, CMOS compatible spin-wave detection schemes in material systems compatible with standard spintronics as well as semiconductor circuitry. Here, we report on the wave-vector independent detection of short-waved spin waves with wavelengths down to 150 nm by the inverse spin Hall effect in spin-wave waveguides made from ultrathin Ta/Co₈Fe₇₂B₂₀/MgO. These findings open up the path for miniaturized scalable interconnects between spin waves and CMOS and the use of ultrathin films made from standard spintronic materials in magnonics.

Guidelines for May-Grünwald-Giemsa staining in haematology and non-gynaecological cytopathology: recommendations of the French Society of Clinical Cytology (SFCC) and of the French Association for Quality Assurance in Anatomic and Cytologic Pathology (AFAQAP)

OBJECTIVE

Since the guidelines of the International Committee for Standardisation in Haematology (ICSH) in 1984 and those of the European Committee for External Quality Assessment Programmes in Laboratory Medicine (EQALM) in 2004, no leading organisation has published technical recommendations for the preparation of air-dried cytological specimens using May-Grünwald-Giemsa (MGG) staining.

DATA SOURCES

Literature data were retrieved using reference books, baseline-published studies, articles extracted from PubMed/Medline and Google Scholar, and online-available industry datasheets.

RATIONALE

The present review addresses all pre-analytical issues concerning the use of Romanowsky's stains (including MGG) in haematology and non-gynaecological cytopathology. It aims at serving as actualised, best practice recommendations for the proper handling of air-dried cytological specimens. It, therefore, appears complementary to the staining criteria of the non-gynaecological diagnostic cytology handbook edited by the United Kingdom National External Quality Assessment Service (UK-NEQAS) in February 2015.

[Mycobacterium simiae pneumonia: a case report]

We report a case of Mycobacterium simiae pneumonia in an immunocompetent women aged 55 years, after a stay in Thailand. The diagnosis was based on culture isolation of non-tuberculous mycobacteria from bronchoalveolar lavage. The culture isolate was identified as M. simiae by biochemical and molecular methods. The patient was treated. Her condition remained stable for 5 years. During the sixth years, a relapse occurred, and a new treatment was prescribed. This is a rare case in view of the absence of any predisposing factor. M. simiae should be considered a possible causative agent of pulmonary disease, even in immunocompetent patients.

[Multi-resistant tuberculosis at the hôpital d'instruction des armées de Libreville (Gabon) about 16 cases]

According to WHO estimates, between 1 and 20% of tuberculosis cases in the world are multiresistant. In Gabon, this prevalence is estimated at 1.9%. In this forward-looking study from March 2006 to August 2010, we report 16 cases of multi-resistant tuberculosis out of 24 suspected resistant samples (persistence of the clinical and radiological signs after three months of well conducted treatment with first-line anti-tuberculous drugs). This study is realized in association with the laboratory of mycobacterium of the Percy military teaching hospital, Clamart, France.

[Evaluation of the SD BIOLINE TB Ag MPT64 Rapid® for the diagnosis of tuberculosis]

The purpose of this study was to evaluate the SD Bioline Ag MPT64 Rapid(®) for identification of the Mycobacterium tuberculosis complex. The method uses an immunochromatographic assay and needs 100 μl of sample taken from liquid culture or colonies suspended. The sensitivity was determined using 99 strains of M. tuberculosis complex and the specificity using 10 nontuberculous mycobacteria and 85 strains other than mycobacteria genus. The test showed excellent sensitivity (99%) and specificity (100%). This technique displays several advantages and is destined to spread in all laboratories and particularly in endemic areas.

[Performances of the assay MTBDRplus(®) in the surveillance of rifampicin resistance in Mycobacterium tuberculosis]

The purpose of the survey was the routine assessment of the MTBDRplus(®) kit performance in the determination and characterization of Mycobacterium tuberculosis resistance to rifampicin. The survey was carried out on a collection of 144 strains (126 of which were resistant to rifampicin) isolated on patients from 15 countries. Sensitivity to antituberculosis drugs was determined by a liquid culture system and the reference method was the amplification and sequencing of a target region of the rpoB gene whose mutations are responsible for rifampicin resistance (codons 507 to 533). The assessed kit was based on a reverse hybridization technique using eight overlapping probes covering the target region and four probes representing the most-frequently observed mutations. The assay performance was found excellent, specificity: 100%, sensitivity: 99.2%; 17 mutations affecting 10 codons were reported, two of which were newly identified.

Clinical characteristics of the smooth tubercle bacilli 'Mycobacterium canettii' infection suggest the existence of an environmental reservoir

Over a 3-year follow-up, 30 out of the 318 unique Mycobacterium tuberculosis complex isolates recovered in the Republic of Djibouti had a smooth-type morphology and were Niacine-negative, the characteristics of 'Mycobacterium canettii' strains. Unlike M. tuberculosis, 'M. canettii' grew on nutrient-poor media at 30°C, and possessed characteristic lipids. They were isolated from respiratory and extra-respiratory sites from patients with typical forms of tuberculosis. Most cases resolved with antibiotic therapy but in two human immunodeficiency virus-positive patients 'M. canettii' infection led to septicaemia and death. No cases of human-to-human transmission were observed. The proportion of tuberculosis cases caused by 'M. canettii' was higher among French patients than among Djiboutian patients. Patients with 'M. canettii' were significantly younger than those with tuberculosis caused by other M. tuberculosis complex strains. Smooth tubercle bacilli could be misidentified as non-tuberculous mycobacteria and appear to be limited to the Horn of Africa. Their characteristics are consistent with the existence of non-human sources of infection.

[Epidemiology of the resistance of Mycobacterium tuberculosis to antituberculosis drugs at the main hospital in Dakar, Senegal. A 4-year retrospective study (2000-2003)]

A retrospective study was carried out from January 2000 to December 2003 to assess the resistance of Mycobacterium tuberculosis to antituberculosis drugs and the impact of this on the treatment result. Two hundred and two patients' files were studied (average age: 36 years; sex-ratio: 1.7). Pulmonary localisation (85.7%) or extrapulmonary localisation (14.3%). HIV status is negative (71.3%), positive (10.8%) or unknown (17.9%). The overall recovery rate is 60.7% (61.4% in HIV-; 46.1% in HIV+), the rate of treatment failure is 2.7% (1.1% in HIV-; 15.4% in HIV+), the death rate due to tuberculosis is 6.3% (2.3% in HIV-; 23.1% in HIV+), and the rate of patients who disappeared from the system is 30.3% (35.2% in HIV-; 14.2% in HIV+). Hepatotoxicity that occurred during treatment is observed in 14.3% of cases (recovery: 56.2%; failure: 6.2%; lost from the system: 18.8%). Eighty-four percent of patients never received antituberculosis treatment (group A) versus 15.8% of patients who had already received one or more antituberculosis drugs (group B). The rates of resistance to isoniazid are 6.4% (A) and 12.5% (B), to rifampicin 1.7% (A) and 12.5% (B), to ethambutol 0.5% (A) and 0% (B), to streptomycin 24.1% (A) and 46.8% (B). The percentage of multiresistant strains is 1% in patients not treated previously and 11% in those who had already received antituberculosis treatment. When the patients are carriers of a strain that is responsive to the treatment administered, the recovery rate is 64.2% versus 46.7% in patients whose strain is resistant to at least one of the treatments administered.

[Evaluation of the Fluo-RAL (RAL) kit for the identification of mycobacteria by fluorescence microscopy]

AIM OF THE STUDY

This study has examined the sensitivity of a commercially available fluorochrome stain, the Fluo-RAL kit (RAL), in comparison to the Degommier's stain as gold standard.

MATERIALS AND METHODS

Hundred and thirty-three twin smears, made directly from samples or after their decontamination with N-acetyl-L-cysteine NaOH, were stained, the first slide with the Degommier's method and the second with the Fluo-RAL kit. The samples were 58 sputums, 31 broncho-aspirations, nine gastric lavages, 11 bronchoalveolar lavages, six pleural fluids, two cerebro-spinal fluids, 11 biopsies, two blood cultures and two deep pus. They were examined with 400 × objective under standard fluorescence UV filter by two laboratory technicians independently. The results were expressed with semi-quantitative mean from 0 to 4+.

RESULTS

Hundred and thirty-two results were agreed in grading between the two methods: 73 negative smears, nine quantified as rare (1+), 11 as few (2+), 32 as moderate (3+) and seven as numerous (4+). The only discrepant result had concerned a positive smear quantified as 1+ with the Degommier's stain and as 2+ with the Fluo-RAL kit. This discrepancy was confirmed after a second examination.

CONCLUSION

After this study, the Fluo-RAL kit was considered as agreed for its daily use in our laboratory. It improves the standardisation of fluorescence microscopy without additional cost or waste of time and reduces the chemical risk in the laboratory. This test, associated with reading using light-emitting diodes, could allow the development of fluorescence microscopy, the higher sensitive method for direct diagnosis of tuberculosis, in poor-resource countries where tuberculosis is a public health problem.

Evaluation of FibroTest-ActiTest in children with chronic hepatitis C virus infection

FibroTest-ActiTest (FT-AT) has been validated in adults with chronic hepatitis C virus (HCV) infection as a noninvasive alternative to liver biopsy (LB), but there are few data of its use in children. The objective of the present study was to evaluate FT-AT in children with HCV infection and to compare FT-AT analysis with liver histology. A total of 43 serum samples from 38 children with chronic HCV infection were analyzed retrospectively. Histological evaluation was performed according to the METAVIR scoring system. In 16 of the children, 21 serum samples were tested with FT-AT and compared to 21 LB (serum/LB pairs) in nontransplanted and liver-transplanted children. FT-AT was also measured in 22 infected children without LB and in 50 healthy controls. FT-AT values in controls were comparable to those of healthy adults, validating the adult FT-AT parameters in children. In most infected children (74%), the FT-AT score was <or = A1-F1. Concordance between FT-AT and METAVIR scores was found in 10 pairs and discordance in 11. FT-AT/METAVIR concordance was better in non-transplanted (8/13 pairs, 62%) than in transplanted (2/8 pairs, 25%) children. A prospective evaluation of FT-AT in non-transplanted children with chronic HCV infection would be worthwhile in future.

Wnt signaling and hepatocarcinogenesis: the hepatoblastoma model

The Wnt/β-catenin pathway plays a key role in liver development, regeneration and tumorigenesis. Among human cancers tightly linked to abnormal Wnt/β-catenin signaling, hepatoblastoma (HB) presents with the highest rate (50-90%) of β-catenin mutations. HB is the most common malignant tumor of the liver in childhood. This embryonic tumor differs from hepatocellular carcinoma by the absence of viral etiology and underlying liver disease, and by distinctive morphological patterns evoking hepatoblasts, the bipotent precursors of hepatocytes and cholangiocytes. Recent studies of the molecular pathogenesis of hepatoblastoma have led to identify two major tumor subclasses resembling early and late phases of prenatal liver development and presenting distinctive chromosomal alterations. It has been shown that the molecular signature of Wnt/β-catenin signaling in hepatoblastoma is mainly imposed by liver context, but differs according to developmental stage. Finally, the differentiation stage of tumor cells strongly influences their invasive and metastatic properties, therefore affecting clinical behavior.

[Glycopeptide-resistant enterococci carriage: Are actual isolation and identification techniques sufficient?]

The monitoring of infection by glycopeptide-resistant enterococci (GRE) is one of the main elements of hospital hygiene policy. It involves systematic rectal swabs in clinics at risk (asymptomatic carriage).

AIM

We compare two GRE screening methods and evaluate a new kit associating multiplex PCR and hybridization (Génotype(®) Enterococcus, Hain Lifescience) on a panel of 448 samples collected over a 4-month period.

PATIENTS AND METHODS

The first method is based on direct inoculation of the sample; the second one involves a preliminary enrichment phase followed by molecular diagnosis allowing the identification of species of enterococci as well as glycopeptide resistance genes.

RESULTS

All the resistant strains were isolated using the enrichment technique. The incidence of GRE (VanA) carriage was 0,55% (two out of 362 patients, two out of 448 isolates) with two Enterococcus faecium VanA. Six Enterococcus gallinarum VanC1 and two Enterococcus casseliflavus VanC2/C3 were also isolated and identified. The main clinics concerned are intensive care and hematology. The two patients with E. faecium VanA had been previously given glycopeptides for 10 days. For three strains, the molecular method allowed to correct prior erroneous results based on rapid identification (RapidID32Strep V2.0).

CONCLUSION

The method using direct samples inoculation underestimates real incidence of GRE carriage. The performances of Génotype(®) Enterococcus molecular method, evaluated for other parameters using reference strains and DNA sequencing, offer new possibilities applicable to routine laboratory.

Role of ALK activation in the development and maintenance of the neoplastic phenotype in neuroblastoma

10008

Background: Activating mutations of the Anaplastic Lymphoma Kinase (ALK) receptor could be responsible for most familial neuroblastoma cases and for up to 15% of somatic cases. The objective of the present study was to further investigate the role of ALK activation in neuroblastoma. Methods: Tissue microarrays were constructed containing 101 primary tumors and 56 paired normal tissues. Sections were immunostained with anti-ALK or anti-P-ALK antibodies, and with antibodies directed against the ALK ligands: PTN (Pleiotrophin) or MDK (Midkine). The Wilcoxon signed rank test was applied for comparison of paired data. Associations with prognostic factors were analyzed using t-tests. Effects of the ALK inhibitor TAE684 (Novartis) on cell proliferation and signaling was evaluated in wild-type or mutated ALK neuroblastoma cell lines and xenografts. Results: ALK was expressed in about 100% of tumors and normal tissues, while phospho-ALK was detected in 5% of normal tissues and 50% of tumors. Sequencing of the kinase domain of ALK showed that its phosphorylation was largely independent of mutations and we found that MDK and PTN ligands were expressed in 66% and 50% of tumors, respectively. Interestingly, ALK, P-ALK, and MDK were expressed at higher levels in tumors as compared with paired normal tissues (p < 0.0001), while PTN showed an inverse tendency, being more expressed in normal tissues (p = 0.07). In tumors, P-ALK was associated with good-prognosis factors, including favorable stages (p = 0.01), absence of MYCN amplification (p = 0.05) and a younger age at diagnosis (p = 0.03). Inhibition of cell proliferation by TAE684 was detectible in all neuroblastoma cell lines, regardless of ALK status. However, TAE684 failed to demonstrate antitumor activity in advanced stage neuroblastoma xenografts expressing either a wild-type or a mutated ALK. Interestingly, ALK pathway activation (P-STAT3, P-AKT) was weak or barely detectible in these xenografts. Conclusions: ALK activation occurs during neuroblastoma oncogenesis, along with a concomitant switch between the expressions of PTN and MDK. However, ALK may not be a relevant therapeutic target since in vivo inhibition showed no antitumor activity.

[Table: see text]

[Management of antenatal fetal abdominal tumors. Clues for the diagnosis of a congenital mesoblastic nephroma]

The prenatal diagnosis of abdominal mass poses the problem of its origin. Renal tumors are rarer than neuroblastoma but they are most often congenital mesoblastic nephroma. The congenital mesoblastic nephroma has a good forecast in spite of a sonographic impressive aspect. MRI can help to locate tumor but cannot tell difference between the different kinds of renal tumor. Prenatal forecast is especially linked with hydramnios and hydrops fetalis. Histolological study of the tumor is important for the prognosis. Two morphological subtypes are currently distinguished: the classic type with a good forecast and the atypical or cellular type. Distant metastases have been related only to the cellular form but especially in infants aged more than 3 months and never in the newborns. The diagnosis of the tumor does not change the mode of delivery except in case of an important volume. Complications are searched during the first days of life: hypertension, hypercalcemia, vomiting, hyperreninemia. Radical nephrectomy is performed after the end of the first week. In case of a classic form, the healing is always obtained. In case of cellular form, distant metastases are searched. In any rate, the follow-up is recommended until the end of the growth.

[Children born with a cleft: treatment at the CHUV in Lausanne]

A cleft can be labial, labial-maxillary, unilateral or bilateral labial-maxillary-palatal, or isolated palatal. A multidisciplinary team includes several specialists who will handle the diverse problems of children born with a cleft. This team will follow the child through each developmental stage and assemble an optimal treatment plan, thus reducing the onus on the family. Depending on the type of cleft and the age of the child, feeding, speech, ORL, dental, orthodontic, esthetic and possibly also psychological problems will be taken care of. This is why cleft treatment starts at the time it is diagnosed, before or after birth, and ends when the child is fully grown. It requires a complete interdisciplinary team and the collaboration with obstetricians and geneticians.

[Eyelid necrosis caused by an hymenopteran insect bite]

We report a case report of extensive eyelid necrosis caused by an insect bite. A 39-year-old man had suffered ocular trauma from a hymenopteran insect in Tunisia. The patient presented with eyelid necrosis. Eyelid necrosis mechanisms following insect bites are discussed and other causes of eyelid necrosis are presented. Eyelid necrosis, often caused by vasoconstrictive medications or animal venoms, notably hymenopteran insect bites, can result in substantial eyelid injury.