Characteristics of mpox positive, versus mpox negative, and mpox unsuspected clients from the Centre of Sexual Health, Public Health Service of Amsterdam, 20 May to 15 September 2022.

BACKGROUND: In May 2022, an outbreak of mpox (monkeypox) in men-who-have-sex-with-men (MSM) emerged and quickly affected over 100 countries. In the early stages of the outbreak, overlap in symptoms with sexually transmitted infections (STI) made triage for mpox testing challenging. More information was needed on whom to screen and the main route of transmission. OBJECTIVES: We aimed to identify characteristics of mpox cases to further strengthen case definitions. We also compared Cycle threshold (Ct) values of the DNA positive mpox samples as a proxy for viral load by body location. METHODS: From 20 May 2022 to 15 September 2022, we tested all MSM who presented with malaise, and/or ulcerative lesions, and/or proctitis and/or a papular-vesicular-pustular eruption attending the Centre of Sexual Health in Amsterdam, the Netherlands, for mpox, with a PCR test. In the same period, 6932 MSM mpox unsuspected clients were not tested. We compared those tested positive for mpox with those tested negative and those unsuspected for mpox. RESULTS: Of the 374 MSM tested, 135 (36%) were positive for mpox. The mpox-positive MSM were older (median age, respectively, 36, 34 and 34 years, p = 0.019) and more often lived with HIV (30% vs. 16% and 7%, p < 0.001). Furthermore, mpox-positive patients more often reported receptive anal sex without a condom, sexualized drug use, more sex partners, and were more often diagnosed with bacterial STI (p < 0.001). Systemic symptoms and anogenital lesions were associated with mpox infection. For mpox-positive patients, anal samples (p = 0.009) and lesional samples (p = 0.006) showed significantly lower median mpox Ct values compared to throat samples. CONCLUSIONS: Mpox-positive patients more often reported receptive anal sex without a condom, had more sex partners and more often lived with HIV. Our results suggest that in the current mpox outbreak among MSM, sexual transmission is the main route.

Human Memory B Cells Producing Potent Cross-Neutralizing Antibodies against Human Parechovirus: Implications for Prevalence, Treatment, and Diagnosis.

UNLABELLED: The family Picornaviridae is a large and diverse group of positive-sense RNA viruses, including human enteroviruses (EVs) and human parechoviruses (HPeVs). The human immune response against EVs and HPeVs is thought to be mainly humoral, and an insufficient neutralizing antibody (Ab) response during infection is a risk factor and can ultimately be life threatening. The accessibility of different antigenic sites and observed cross-reactivity make HPeVs a good target for development of therapeutic human monoclonal antibodies (MAbs). In this study, we generated two different human MAbs specific for HPeV by screening culture supernatants of Ab-producing human B cell cultures for direct neutralization of HPeV1. Both MAbs showed HPeV1-specific neutralization as well as neutralization of HPeV2. One antibody, AM18, cross-neutralized HPeV4, -5, and -6 and coxsackievirus A9 (CV-A9). VP1 capsid protein-specific assays confirmed that AM18 bound VP1 of HPeV1, -2, and -4 with high affinity (11.5 pM). In contrast, the HPeV1-specific MAb AM28, which neutralized HPeV1 even more efficiently than did AM18, showed no cross-reactivity with HPeV3 to -6 or other EVs and did not bind any of the capsid proteins, suggesting that AM28 is specific for a conformation-dependent, nonlinear epitope on the virus. The discovery of MAbs that are cross-reactive between HPeVs may help development of HPeV treatment options with antibodies and vaccine design based on epitopes recognized by these antibodies. IMPORTANCE: HPeV infections are widespread among young children and adults, causing a broad range of disease. Infections can be severe and life threatening, while no antiviral treatment is available. Given that the absence of neutralizing Abs is a risk factor for severe disease in infants, treatment of picornavirus infections with MAbs would be a therapeutic option. To study antibody neutralization of HPeV in more detail, we generated two different HPeV1-specific human MAbs. Both MAbs show HPeV1-specific neutralization and cross-neutralized HPeV2. One MAb also cross-neutralized other HPeVs. Surprisingly, this MAb also neutralized CV-A9. These MAbs provide a unique tool for further research and for the diagnosis (antigen detection) and possible treatment of HPeV infections.

Genetic and antigenic structural characterization for resistance of echovirus 11 to pleconaril in an immunocompromised patient.

Pleconaril is a capsid inhibitor used previously to treat enterovirus infections. A pleconaril-resistant echovirus 11 (E11) strain was identified before pleconaril treatment was given in an immunocompromised patient. The patient was also treated with intravenous Ig (IVIg) for a long period but remained unresponsive. The pleconaril-resistant strains could not be neutralized in vitro, confirming IVIg treatment failure. To identify the basis of pleconaril resistance, genetic and structural analyses were conducted. Analysis of a modelled viral capsid indicated conformational changes in the hydrophobic pocket that could prevent pleconaril docking. Substitutions (V117I, V119M and I188L) in the pleconaril-resistant viruses were found in the pocket region of VP1. Modelling suggested that V119M could confer resistance, most probably due to the protruding sulfate side chain of methionine. Although pleconaril resistance induced in vitro in a susceptible E11 clinical isolate was characterized by a different substitution (I183M), resistance was suggested to also result from a similar mechanism, i.e. due to a protruding sulfate side chain of methionine. Our results showed that resistant strains that arise in vivo display different markers from those identified in vitro and suggest that multiple factors may play a role in pleconaril resistance in patient strains. Based on IVIg treatment failure, we predict that one of these factors could be immune related. Thus, both IVIg and capsid inhibitors target the viral capsid and can induce mutations that can be cross-reactive, enabling escape from both IVIg and the drug. This could limit treatment options and should be investigated further.

The iron content of serum ferritin: physiological importance and diagnostic value.

In this paper we present a method for determining the iron saturation of ferritin as a possible independent predictor of iron stores. Serum ferritin was purified by immunochemical precipitation, and could be completely recovered from serum without any contamination from transferrin. The iron content of the precipitated ferritin was determined by flameless atomic absorption spectrophotometry (FAAS) and the ferritin-iron saturation was calculated using the original serum ferritin concentration. The intra- and inter-assay variation coefficients were 4.2% and 13.4% respectively. The first results with this assay indicate that serum ferritin contains a considerable amount of iron. Furthermore the results show that the iron saturation of ferritin in patients with acute phase response is significantly lower than the saturation found in healthy volunteers (19.3% and 24.3% respectively). These results suggest a possible role for the ferritin-iron saturation in the assessment of iron stores in patients suffering from acute phase response. In addition, the considerable amount of iron in ferritin suggests the need to revise the physiological role of this substance in relation to the serum iron homeostasis.