We describe 2 children with persistent fever and profuse diarrhea who developed signs of mucocutaneous involvement (conjunctivitis, fissured lips, skin rash, erythema, and edema of the hands and feet). Blood tests revealed elevated markers of inflammation, lymphopenia, thrombocytopenia, and complement consumption. Afterward, diffuse edema with hypoalbuminemia appeared in the context of a capillary leak syndrome. In both patients, repeated nasal swabs were negative for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but each patient had high titers of immunoglobulin G and immunoglobulin M against the SARS-CoV-2 virus. The negative PCR results in the presence of immunoglobulin M and immunoglobulin G suggested that the inflammatory response developed in the late phase of viral infection, when SARS-CoV-2 was not detectable in the upper airway. In this report, we describe patients with what we propose to name as SARS-CoV-2–induced Kawasaki-like hyperinflammatory syndrome. SARS-CoV-2–induced Kawasaki-like hyperinflammatory syndrome seems to be caused by a delayed response to SARS-CoV-2. It resembles Kawasaki disease complicated by macrophage activation syndrome, although it has peculiar features, such as prodromal diarrhea, capillary leak syndrome, and myocardial dysfunction. Intravenous corticosteroid treatment appears to be helpful.

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To accurately diagnose COVID-19 infection and its time-dependent progression, the rapid, sensitive, and noninvasive determination of immunoglobulins A specific to SARS-CoV-2 (IgA) in saliva and serum is needed to complement tests that detect immunoglobulins G and M. We have developed a dual optical/chemiluminescence format of a lateral flow immunoassay (LFIA) immunosensor for IgA in serum and saliva. A recombinant nucleocapsid antigen specifically captures SARS-CoV-2 antibodies in patient specimens. A labelled anti-human IgA reveals the bound IgA fraction. A dual colorimetric and chemiluminescence detection enables the affordable and ultrasensitive determination of IgA to SARS-CoV-2. Specifically, a simple smartphone-camera-based device measures the colour signal provided by nanogold-labelled anti-human IgA. For the ultrasensitive chemiluminescence transduction, we used a contact imaging portable device based on cooled CCD, and measured the light signal resulting from the reaction of the HRP-labelled anti-human IgA with a H 2 O 2 /luminol/enhancers substrate. A total of 25 serum and 9 saliva samples from infected and/or recovered individuals were analysed by the colorimetric LFIA, which was sensitive and reproducible enough for the semi-quantification of IgA in subjects with a strong serological response and in the early stage of COVID-19 infection. Switching to CL detection, the same immunosensor exhibited higher detection capability, revealing the presence of salivary IgA in infected individuals. For the patients included in the study ( n = 4), the level of salivary IgA correlated with the time elapsed from diagnosis and with the severity of the disease. This IgA-LFIA immunosensor could be useful for noninvasively monitoring early immune responses to COVID-19 and for investigating the diagnostic/prognostic utility of salivary IgA in the context of large-scale screening to assess the efficacy of SARS-CoV-2 vaccines.

A duplex polymerase chain reaction (PCR) was developed to identify the milk of bovine and buffalo species in cheese products, particularly in mozzarella cheese, a typical Italian cheese made from buffalo's milk. Two sets of primers were designed on the basis of the alignment of the sequence codifying mitochondrial cyt b available in the GenBank database. The primers proved to be species-specific, giving rise to 279-bp (bovine) and 192-bp (buffalo) amplified fragments. Since the amplification conditions for bovine and buffalo primers were identical, a duplex PCR was successfully applied to identify the two species in a single reaction step. This technique, when used to test cheese products from the retail trade, allowed the detection of partial or even total substitution of cow's milk for buffalo's milk, in some cases in samples of cheese misleadingly labeled "pure buffalo" mozzarella.