Resistance of SARS-CoV-2 variants to neutralization by antibodies induced in convalescent patients with COVID-19.

Administration of convalescent plasma or neutralizing monoclonal antibodies (mAbs) is a potent therapeutic option for coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, SARS-CoV-2 variants with mutations in the spike protein have emerged in many countries. To evaluate the efficacy of neutralizing antibodies induced in convalescent patients against emerging variants, we isolate anti-spike mAbs from two convalescent COVID-19 patients infected with prototypic SARS-CoV-2 by single-cell sorting of immunoglobulin-G-positive (IgG+) memory B cells. Anti-spike antibody induction is robust in these patients, and five mAbs have potent neutralizing activities. The efficacy of most neutralizing mAbs and convalescent plasma samples is maintained against B.1.1.7 and mink cluster 5 variants but is significantly decreased against variants B.1.351 from South Africa and P.1 from Brazil. However, mAbs with a high affinity for the receptor-binding domain remain effective against these neutralization-resistant variants. Rapid spread of these variants significantly impacts antibody-based therapies and vaccine strategies against SARS-CoV-2.

Targeted Phototherapy for Malignant Pleural Mesothelioma: Near-Infrared Photoimmunotherapy Targeting Podoplanin.

Malignant pleural mesothelioma (MPM) has extremely limited treatment despite a poor prognosis. Moreover, molecular targeted therapy for MPM has not yet been implemented; thus, a new targeted therapy is highly desirable. Near-infrared photoimmunotherapy (NIR-PIT) is a recently developed cancer therapy that combines the specificity of antibodies for targeting tumors with toxicity induced by the photoabsorber after exposure to NIR-light. In this study, we developed a new phototherapy targeting podoplanin (PDPN) for MPM with the use of both NIR-PIT and an anti-PDPN antibody, NZ-1. An antibody-photosensitizer conjugate consisting of NZ-1 and phthalocyanine dye was synthesized. In vitro NIR-PIT-induced cytotoxicity was measured with both dead cell staining and luciferase activity on various MPM cell lines. In vivo NIR-PIT was examined in both the flank tumor and orthotopic mouse model with in vivo real-time imaging. In vitro NIR-PIT-induced cytotoxicity was NIR-light dose dependent. In vivo NIR-PIT led to significant reduction in both tumor volume and luciferase activity in a flank model (p < 0.05, NIR-PIT group versus NZ-1-IR700 group). The PDPN-targeted NIR-PIT resulted in a significant antitumor effect in an MPM orthotopic mouse model (p < 0.05, NIR-PIT group versus NZ-1-IR700 group). This study suggests that PDPN-targeted NIR-PIT could be a new promising treatment for MPM.

Near infrared photoimmunotherapy targeting DLL3 for small cell lung cancer.

BACKGROUND: Small cell lung cancer (SCLC) has a poor prognosis, and its treatment options are limited. Delta-like protein 3 (DLL3) is expressed specifically in SCLC and is considered a promising therapeutic target for patients with this disease. Rovalpituzumab tesirine (Rova-T) was the first antibody-drug conjugate targeting DLL3. Although Rova-T development was unfortunately terminated, DLL3 remains an ideal target for SCLC. Near infrared photoimmunotherapy (NIR-PIT) is a new form of cancer treatment that employs an antibody-photosensitiser conjugate followed by NIR light exposure and damage target cells specifically. In this study, we demonstrate DLL3-targeted NIR-PIT to develop a novel molecularly targeted treatment for SCLC. METHODS: The anti-DLL3 monoclonal antibody rovalpituzumab was conjugated to an IR700 photosensitiser (termed 'rova-IR700'). SCLC cells overexpressing DLL3 as well as non-DLL3-expressing controls were incubated with rova-IR700 and then exposed to NIR-light. Next, mice with SCLC xenografts were injected with rova-IR700 and irradiated with NIR-light. FINDINGS: DLL3-overexpressing cells underwent immediate destruction upon NIR-light exposure, whereas the control cells remained intact. The xenograft in mice treated with rova-IR700 and NIR-light shrank markedly, whereas neither rova-IR700 injection nor NIR-light irradiation alone affected tumour size. INTERPRETATION: Our data suggest that targeting of DLL3 using NIR-PIT could be a novel and promising treatment for SCLC. FUNDING: Research supported by grants from the Program for Developing Next-generation Researchers (Japan Science and Technology Agency), KAKEN (18K15923, JSPS), Medical Research Encouragement Prize of The Japan Medical Association, The Nitto Foundation, Kanae Foundation for the Promotion of Medical Science.

Two cases with Hb Andrew-Minneapolis showing high or low-normal HbA1c levels depending on the measurement method.

We experienced two cases of Hb Andrew-Minneapolis with high or low-normal HbA1c levels depending on the measurement method. Case 1 was a 25-year-old male, and case 2 was a 32-year-old pregnant woman. Both cases showed normal glucose tolerance levels and glycated albumin within the reference range. In both cases, the high-performance liquid chromatography (HPLC) method (standard mode) showed high HbA1c levels of 6.8% and 6.5%, respectively, while the HbA1c levels measured by immunoassay were low normal at 4.6% in both cases. Globin gene analysis detected heterozygous ß-chain mutations (ß144Lys → Asn) in both cases, which resulted in the diagnosis of Hb Andrew-Minneapolis. In case 1, a high-resolution HPLC chromatogram showed multiple abnormal peaks; two unknown peaks in addition to variant hemoglobin (HbX0) and glycation products of variant hemoglobin (HbX1c) were observed after in vitro glycation reaction. Although the details of unknown peaks were not identified, those might be modified hemoglobin associated with variant hemoglobin. The presence of unknown peaks could cause high HbA1c levels measured by HPLC (standard mode). Furthermore, the HbA1c level measured by immunoassay was increased to 4.9% within the reference range after adjustment for modified hemoglobin in case 1. Consequently, the high HbA1c levels measured by HPLC (standard mode) and the low-normal HbA1c level measured by immunoassay might be due to modified hemoglobin associated with variant hemoglobin.

A case of monoclonal gammopathy of undetermined significance with abnormal low levels of plasma glycated albumin by M protein.

BACKGROUND: It is known that an immunoglobulin abnormality affects various clinical laboratory measurements and leads to abnormal values. We experienced a case of monoclonal gammopathy of undetermined significance (MGUS) showing a falsely low plasma glycated albumin (GA) level. CASE REPORT: The patient was a 75-y-old male who visited our hospital for thrombocytosis identified during a medical checkup. Based on further examinations, he was diagnosed with MGUS (IgM-κ type). Laboratory examinations revealed that the plasma GA level was significantly low at -1.3% but the serum GA level was reasonable at 15.5%. We investigated the cause of the falsely low plasma GA level. RESULTS: The patient's plasma became turbid after mixing with the first reagent for GA measurement. The plasma GA level was increased by dilution of the plasma. The plasma GA level was falsely decreased only at the time of measurement on a sample collected using a blood-collecting tube with heparin sodium. The GA level was decreased by adding heparin sodium to the patient's serum, whereas the GA level was increased by neutralization of the patient's plasma with protamine sulfate. The GA level was increased after adding polyethylene glycol to the patient's plasma. Serum GA levels in healthy controls were decreased by adding purified M protein from the patient's serum. CONCLUSIONS: We report a patient with MGUS whose plasma GA concentration was falsely decreased by M protein when blood was drawn in a heparin sodium-containing tube.