COVID-19 convalescent plasma as long-term therapy in immunodeficient patients?

OBJECTIVES: The patients with hematological malignancies are a vulnerable group to COVID-19, due to the immunodeficiency resulting from the underlying disease and oncological treatment that significantly impair cellular and humoral immunity. Here we report on a beneficial impact of a passive immunotherapy with convalescent plasma to treat a prolonged, active COVID-19 infection in a patient with a history of nasopharyngeal diffuse large B-cell lymphoma treated with the therapy inducing substantial impairment of particularly humoral arm of immune system. The specific aim was to quantify SARS-CoV2 neutralizing antibodies in a patient plasma during the course of therapy. MATERIALS AND METHODS: Besides the standard of care treatment and monitoring, neutralizing antibody titers in patient's serum samples, calibrated according to the First WHO International Standard for anti-SARS-CoV-2 immunoglobulin (human), were quantified in a time-dependent manner. During the immunotherapy period peripheral blood flow cytometry immunophenotyping was conducted to characterize lymphocyte subpopulations. RESULTS: The waves of clinical improvements and worsening coincided with transfused neutralizing antibodies rises and drops in the patient's systemic circulation, proving their contribution in controlling the disease progress. Besides the patient's lack of own humoral immune system, immunophenotyping analysis revealed also the reduced level of helper T-lymphocytes and immune exhaustion of monocytes. CONCLUSION: Therapeutic approach based on convalescent plasma transfusion transformed a prolonged, active COVID-19 infection into a manageable chronic disease.

Simple alternative to sialic acid determination in meningococcal polysaccharides W or Y.

Physicochemical methods are the primary tests used to ensure that batches of meningococcal polysaccharide (PS) antigens are manufactured consistently to those shown to be safe and effective in clinical trials. Although modern physicochemical methods of analysis providing structural information about the antigens have been developed and used, simpler assays, which can be readily validated, are still in use for polysaccharide batch release. The simple and cheap method for Neisseria meningitidis serogroup W or Y polysaccharide (MenW or MenY PS) content quantification has been developed. This colorimetric method is based on the galactose or glucose quantification in MenW or MenY PS hydrolysate, respectively. Intra- and inter-assay precision and accuracy of the novel method have been demonstrated, in comparison to the same properties of the current regulatory approved method for the same purpose - sialic acid quantification. We provided the calculation of the possible future regulatory requirement for the galactose or glucose content in MenW or MenY PS, respectively, and revealed in detail the stoichiometric calculation behind it.

Factors influencing preclinical in vivo evaluation of mumps vaccine strain immunogenicity.

Immunogenicity testing in animals is a necessary preclinical assay for demonstration of vaccine efficacy the results of which are often the basis for the decision whether to proceed or withdraw the further development of the novel vaccine candidate. However, in vivo assays are rarely, if at all, optimized and validated. Here we clearly demonstrate the importance of in vivo assay (mumps virus immunogenicity testing in guinea pigs) optimization for gaining reliable results and the suitability of Fractional factorial design of experiments (DoE) for such a purpose. By the use of DoE with resolution IV (2IV((4-1))) we clearly revealed that the parameters significantly increasing assay sensitivity were interval between animal immunizations followed by the body weight of experimental animals. The quantity (0 versus 2%) of the stabilizer (fetal bovine serum, FBS) in the sample was shown as non-influencing parameter in DoE setup. However, the separate experiment investigating only the FBS influence, and performed under other parameters optimally set, showed that FBS also influences the results of immunogenicity assay. Such finding indicated that (a) factors with strong influence on the measured outcome can hide the effects of parameters with modest/low influence and (b) the matrix of mumps virus samples to be compared for immunogenicity must be identical for reliable virus immunogenicity comparison. Finally the 3 mumps vaccine strains widely used for decades in the licensed vaccines were for the first time compared in an animal model, and results obtained were in line with their reported immunogenicity in human population supporting the predictive power of the optimized in vivo assay.