Demonstration of Multiple Hemagglutinating Factors in Sera of Ragweed-Allergic Individuals with the Help of Immunosorbents

Summary Skin-sensitizing and hemagglutinating antibodies were completely removed from sera of nontreated ragweed-sensitive individuals by absorption with adequate amounts of erythrocyte-WSR conjugates. However, when increasing volumes of these sera were added to a constant amount of immunosorbent, differences in the ability of skin-sensitizing and hemagglutinating antibodies to combine with the ragweed antigens on the immunosorbent were revealed. Thus, the immunosorbent was saturated with respect to skin-sensitizing antibodies before reaching its full capacity for the removal of hemagglutinins. Similar conclusions were derived from absorption experiments in which serum fractions, obtained by chromatography on DEAE-cellulose, were used. Moreover, it was shown that skin-sensitizing antibodies could be displaced from the immunosorbent by the addition of serum fractions containing only hemagglutinins. From this study, it was also concluded that there exists a spectrum of hemagglutinating antibodies both in terms of their physicochemical properties, and in terms of their affinity for the antigens present on the immunosorbent. It was shown that even if skin-sensitizing antibodies have hemagglutinating ability, their contribution to the over-all hemagglutination titer is only minimal. Therefore, a simple relationship between hemagglutination and Prausnitz-Küstner titers cannot be expected.</jats:p

Prevalence of Gastrointestinal Symptoms in Severe Acute Respiratory Syndrome Coronavirus 2 Infection: Results of the Prospective Controlled Multinational GI-COVID-19 Study

INTRODUCTION: Gastrointestinal (GI) symptoms in coronavirus-19 disease (COVID-19) have been reported with great variability and without standardization. In hospitalized patients, we aimed to evaluate the prevalence of GI symptoms, factors associated with their occurrence, and variation at 1 month. METHODS: TheGI-COVID-19 is a prospective,multicenter, controlled study. Patientswith and without COVID-19 diagnosis were recruited at hospital admission and asked for GI symptoms at admission and after 1 month, using the validated Gastrointestinal Symptom Rating Scale questionnaire. RESULTS: The study included 2036 hospitalized patients. A total of 871 patients (575 COVID1and 296 COVID2) were included for the primary analysis. GI symptoms occurred more frequently in patients with COVID-19 (59.7%; 343/575 patients) than in the control group (43.2%; 128/296 patients) (P &lt; 0.001). Patients with COVID-19 complained of higher presence or intensity of nausea, diarrhea, loose stools, and urgency as compared with controls. At a 1-month follow-up, a reduction in the presence or intensity of GI symptoms was found in COVID-19 patients with GI symptoms at hospital admission. Nausea remained increased over controls. Factors significantly associated with nausea persistence in COVID-19 were female sex, high body mass index, the presence of dyspnea, and increased C-reactive protein levels. DISCUSSION: The prevalence of GI symptoms in hospitalized patients with COVID-19 is higher than previously reported. Systemic and respiratory symptoms are often associated with GI complaints. Nausea may persist after the resolution of COVID-19 infection