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.

High infection rate of bank voles (Myodes glareolus) with Puumala virus is associated with a winter outbreak of haemorrhagic fever with renal syndrome in Croatia.

An outbreak of haemorrhagic fever with renal syndrome (HFRS) started on Medvednica mountain near Zagreb in January 2012. In order to detect the aetiological agent of the disease in small rodents and to make the link with the human outbreak, rodents were trapped at four different altitudes. Using nested RT-PCR, Puumala virus (PUUV) RNA was detected in 41/53 (77·4%) bank voles (Myodes glareolus) and Dobrava virus (DOBV) RNA was found in 6/61 (9·8%) yellow-necked mice (Apodemus flavicollis). Sequence analysis of a 341-nucleotide region of the PUUV S segment, obtained from all infected bank voles and five HFRS patients, showed 98·8-100% sequence similarity, indicating that the patients were probably exposed to PUUV on Medvednica mountain. A very large bank-vole population combined with an extremely high infection rate of PUUV was responsible for this unusual winter outbreak of HFRS in Croatia.

Molecular characterization of dengue virus 1 from autochthonous dengue fever cases in Croatia.

In the summer of 2010, two autochthonous dengue fever cases were detected in Croatia. Here we report the retrospective detection of an additional case of dengue fever, representing the first sustained autochthonous transmission in Europe since 1928. In addition, we present the phylogenetic analyses based on two sequences from the Peljesac peninsula, southern Croatia. The sequences were identified as dengue virus genotype 1 and recovered from two out of the three Peljesac patients in whom infection occurred.