[Effects of Covid-19 Pandemic on the Vaccine Activities on a Reference Immunization Center in Treichville, Côte D'ivoire]

Introduction

Depuis le 11 mars 2020, la Côte d'Ivoire est touchée par l'épidémie de coronavirus, déclarée ce même jour comme pandémie par l'OMS. Au 11 mars 2021, soit un an après la pandémie, la Côte d'Ivoire a notifié 36824 cas de patients atteints de Covid-19 et parmi eux 211 sont décédés. Au 31 mai 2020, la Côte d'Ivoire avait déjà notifié 2833 cas et 33 décès. À cette période, de fausses rumeurs circulaient en Afrique sur la mise en place d'essais cliniques sur des candidats vaccins. L'impact de ces rumeurs sur l'utilisation globale des services de santé devait être mesuré et notamment sur les centres de vaccination.

Objectifs

L'objectif de cette étude était de déterminer les effets de la pandémie sur les activités des services de vaccination de l'Institut national d'hygiène publique. L'étude était basée sur les rapports d'activité de son centre de vaccination de Treichville à Abidjan, composé de quatre services: Centre des vaccinations internationales, Service de vaccination des collectivités, Centre antirabique, Unité de vaccination du Programme élargi de vaccination.

Résultats

Au Centre des vaccinations internationales, les activités ont chuté d'environ 50% en mars, de 86% en avril et de 82% en mai par rapport à 2018 et 2019. Pour les vaccinations communautaires, les activités ont diminué d'environ 26% en mars et de 99% en avril et mai. Au Centre de lutte contre la rage, ces diminutions sont estimées à 38% en avril et à 45% en mai. Les réductions les plus importantes concernent les vaccinations contre la fièvre jaune et les méningites.

Conclusion

La baisse de la fréquentation des services de vaccination pourrait augmenter le risque de survenue d'épidémies notamment de fièvre jaune qui sont déjà récurrentes à Abidjan. Des mesures de sensibilisation et de rattrapage vaccinal devraient être entreprises et d'autres études devraient être menées pour déterminer l'impact de la pandémie sur les activités de vaccination.

Human proteinase 3 resistance to inhibition extends to alpha-2 macroglobulin

Polymorphonuclear neutrophils contain at least four serine endopeptidases, namely neutrophil elastase (NE), proteinase 3 (PR3), cathepsin G (CatG), and NSP4, which contribute to the regulation of infection and of inflammatory processes. In physiological conditions, endogenous inhibitors including α2-macroglobulin (α2-M), serpins [α1-proteinase inhibitor (α1-PI)], monocyte neutrophil elastase inhibitor (MNEI), α1-antichymotrypsin, and locally produced chelonianins (elafin, SLPI) control excessive proteolytic activity of neutrophilic serine proteinases. In contrast to human NE (hNE), hPR3 is weakly inhibited by α1-PI and MNEI but not by SLPI. α2-M is a large spectrum inhibitor that traps a variety of proteinases in response to cleavage(s) in its bait region. We report here that α2-M was more rapidly processed by hNE than hPR3 or hCatG. This was confirmed by the observation that the association between α2-M and hPR3 is governed by a k_ass in the ≤ 10⁵  m^-1 ·s^-1 range. Since α2-M-trapped proteinases retain peptidase activity, we first predicted the putative cleavage sites within the α2-M bait region (residues 690-728) using kinetic and molecular modeling approaches. We then identified by mass spectrum analysis the cleavage sites of hPR3 in a synthetic peptide spanning the 39-residue bait region of α2-M (39pep-α2-M). Since the 39pep-α2-M peptide and the corresponding bait area in the whole protein do not contain sequences with a high probability of specific cleavage by hPR3 and were indeed only slowly cleaved by hPR3, it can be concluded that α2-M is a poor inhibitor of hPR3. The resistance of hPR3 to inhibition by endogenous inhibitors explains at least in part its role in tissue injury during chronic inflammatory diseases and its well-recognized function of major target autoantigen in granulomatosis with polyangiitis.

Consequences of cathepsin C inactivation for membrane exposure of proteinase 3, the target antigen in autoimmune vasculitis

Membrane-bound proteinase 3 (PR3^m) is the main target antigen of anti-neutrophil cytoplasmic autoantibodies (ANCA) in granulomatosis with polyangiitis, a systemic small-vessel vasculitis. Binding of ANCA to PR3^m triggers neutrophil activation with the secretion of enzymatically active PR3 and related neutrophil serine proteases, thereby contributing to vascular damage. PR3 and related proteases are activated from pro-forms by the lysosomal cysteine protease cathepsin C (CatC) during neutrophil maturation. We hypothesized that pharmacological inhibition of CatC provides an effective measure to reduce PR3^m and therefore has implications as a novel therapeutic approach in granulomatosis with polyangiitis. We first studied neutrophilic PR3 from 24 patients with Papillon-Lefèvre syndrome (PLS), a genetic form of CatC deficiency. PLS neutrophil lysates showed a largely reduced but still detectable (0.5-4%) PR3 activity when compared with healthy control cells. Despite extremely low levels of cellular PR3, the amount of constitutive PR3^m expressed on the surface of quiescent neutrophils and the typical bimodal membrane distribution pattern were similar to what was observed in healthy neutrophils. However, following cell activation, there was no significant increase in the total amount of PR3^m on PLS neutrophils, whereas the total amount of PR3^m on healthy neutrophils was significantly increased. We then explored the effect of pharmacological CatC inhibition on PR3 stability in normal neutrophils using a potent cell-permeable CatC inhibitor and a CD34⁺ hematopoietic stem cell model. Human CD34⁺ hematopoietic stem cells were treated with the inhibitor during neutrophil differentiation over 10 days. We observed strong reductions in PR3^m, cellular PR3 protein, and proteolytic PR3 activity, whereas neutrophil differentiation was not compromised.

[Malaria serology test: what contribution does it make in an endemic country such as Ivory Coast?]

INTRODUCTION

Malaria serology test seems to have attracted very little interest in endemic countries such as Ivory Coast. However, this examination has been regularly performed in the parasitology laboratory at the Training and Research Unit of Medical Sciences in Abidjan. Our study aimed to highlight the contribution of malaria serology test in our endemic country context.

METHODS

We conducted a retrospective study of malaria serology test using Falciparum-Spot IF (bioMerieux) kit for the detection of IgG antiplasmodial antibodies. It included all malaria serology tests performed from January 2007 to February 2011 and whose results were available in the registry.

RESULTS

In total, 136 patients were selected. The average age of patients was 36,3 years, ranging from 1 to 81 years, and sex ratio was 0,97. Indications for malaria serology test were varied and dominated by splenomegaly (49.3%), cytopenias (14.7%), indeterminate fever (13.2%). Almost all of the patients (98.5%) had antiplasmodial antibodies with high medium titer of 1057,35IU/ml. There was no link between age and Ab titer, which was higher in cytopenias, prolonged fevers and the splenomegaly.

CONCLUSION

Malaria serology test seems to have attracted very little interest in routine clinical practice provided in our endemic area because, whatever the reason of the prescription, titers were high.

[Heterophile interference: an experimental method of depleting rheumatoid factor from sera in Abidjan, Côte d'Ivoire]

Rheumatoid factor (RF) is a major source of interference in immunoassays. Several methods have been proposed to eliminate interference. We experimented with a new technique based on the depletion of rheumatoid factor from serum samples. Our study included 150 samples, 64 of them positive for RF. Depletion was performed by the adsorption of RF from the sample by latex beads sensitized with human IgG anti-RF. After precipitation of the complexes formed, the supernatant was tested for RF. Finally, we assessed the performance of this RF depletion method with two tests: ELISA Enzygnost Enzygnost anti-HBs micro-Behring and IFI falciparum Ref 75521 Biomerieux. We compared the percentages of false-negative and false-positive results of these tests before and after depletion of the RF-positive serum samples. Efficiency index is 92.2% and the performance of the two immunoassay tests improved significantly by a factor of 2 to 25 after depletion. In addition, this technique is easy, inexpensive, fast, and suitable to our limited resources as a developing country. It should be extended to other immunological tests for validation of the results.

Leiomyomatosis peritonealis disseminata and pregnancy: a case report

Leimyomatosis peritonealis disseminata (LPD) is a benign tumor of smooth muscle tissue. It is rare and is characterized by the development of multiple peritoneal nodules mimicking peritoneal carcinomatosis. We report a case of LPD diagnosed in a 35-year-old patient, G4/P1, without any major gynecological history. The patient underwent an elective cesarean section at 42 weeks, during which numerous peritoneal nodules ranging in size from 0.1 to 0.5 cm were found. Microscopic examination showed a proliferation of smooth-muscle cells without mitosis or atypia or necrosis.

Primitive breast localisation of Buruli ulcer in an endemic zone: a rare case

A case of Buruli ulcer with primitive breast localisation with evident epidemiological and clinical aspects is reported. This localisation is exceptional; the differential diagnosis with breast cancer is essential. If diagnosed early, it can be cured with surgery, broad-spectrum antibiotherapy and thermotherapy.

[Direct sputa examination limits in tuberculosis active detection in 200 immigrant candidates in United States of America]

The Côte-d'Ivoire Pasteur Institute unit of Tuberculous and Nontuberculous Mycobacteria carried out 600 smears stained by Ziehl-Neelsen in 200 immigrant candidates for the U.S.A. The sputa of 44 of them were put in culture on Lowenstein-Jensen medium. Eight (4%) candidates had active pulmonary tuberculosis among whom 5 had smear negative sputum. The pulmonary tuberculosis active detection performed on target population with accessible and sensitive tool can contribute to strengthen the fight against tuberculosis in endemic areas.

[Value and limits of microscopy of exudates in Mycobacterium ulcerans cutaneous infection in Côte d'Ivoire]

The objective of this study was to estimate the interest and the limits of skin exudate microscopy for patients with chronic ulceration with clinically suspected Buruli's ulcer and living in an endemic area in Côte d'Ivoire. Two stained smears, one with Ziehl-Neelsen and the other Dugomier staining, were produced from 140 samples obtained after a swab of skin lesions. The positive smear rate for the acid fast bacilli (AFB) was respectively 16.4% and 12.9% for Dugomier and Ziehl-Neelsen staining. The ulceration with less than one year of evolution have high AFB rates of 15.8% for Ziehl-Neelsen staining and 21.1% for Dugomier's. Microscopic examination of skin exudate in face of ulceration, clinically suspected to be a Buruli's ulcer is not the best tool for biological diagnosis, due to poor technical sensibility. Nevertheless, it remains a good first means of investigation in an endemoepidemic area.

X-ray diffraction evidence for transient composition effects in MOVPE multilayer growth for Ga1−x Al x As alloys

X-ray rocking-curve analysis is applied to the detection of artifacts in multilayer epitactic growth of III–V ternary compounds by metal–organic vapour-phase epitaxy (MOVPE). Transient spikes in the composition result in unwanted additional thin layers whose presence disturbs the interference pattern expected from the designed heterostructures, thus modifying the oscillating part of the reflection profile. X-ray methods and secondary-ion mass spectroscopy (SIMS) lead to descriptions of the actual layer stacking in good agreement with each other.