Orthogonal immunoassays for IgG antibodies to SARS-CoV-2 antigens reveal that immune response lasts beyond 4 mo post illness onset.

Immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the current pandemic remains a field of immense interest and active research worldwide. Although the severity of acute infection may depend on the intensity of innate and adaptive immunity, leading to higher morbidity and mortality, the longevity of IgG antibodies, including neutralizing activity to SARS-CoV-2, is viewed as a key correlate of immune protection. Amid reports and concern that there is a rapid decay of IgG antibody levels within 1 mo to 2 mo after acute infection, we set out to study the pattern and duration of IgG antibody response to various SARS-CoV-2 antigens in asymptomatic and symptomatic patients in a community setting. Herein, we show the correlation of IgG anti-spike protein S1 subunit, receptor binding domain, nucleocapsid, and virus neutralizing antibody titers with each other and with clinical features such as length and severity of COVID-19 illness. More importantly, using orthogonal measurements, we found the IgG titers to persist for more than 4 mo post symptom onset, implying that long-lasting immunity to COVID-19 from infection or vaccination might be observed, as seen with other coronaviruses such as SARS and Middle East respiratory syndrome.

Rare Pedal Manifestation of Diffuse Multiple Myeloma Lesions.

Multiple myeloma is a malignancy of plasma cell proliferation leading to production of monoclonal immunoglobins. Among the classic features of multiple myeloma are bone lesions, which typically manifest in the axial skeleton, vertebrae, pelvis, skull, ribs, and proximal extremities. The several types of multiple myeloma include symptomatic multiple myeloma, monoclonal gammopathy of undetermined significance, smoldering/indolent myeloma, and solitary plasmacytoma of bone. Although rare, plasmacytomas of the foot and ankle have been described in published studies. We present, to the best of our knowledge, the first description of classic diffuse myelomatosis lesions associated with symptomatic myeloma in the foot of a patient with advanced disease who was treated in the podiatric surgery clinic for pathologic fracture.

Recovery of kidney function following delayed use of Theralite™ dialyzer in a patient with myeloma cast nephropathy.

We report the case of a 60- year- old man who presented with newly diagnosed multiple myeloma complicated by biopsy-proven acute cast nephropathy, requiring hemodialysis, plasmapheresis and chemotherapy. After remaining dialysis dependent for 5 weeks, a high cut-off (HCO) dialyzer, intended to use for the removal of plasma substances with a molecular weight of up to 45 kDa such as free light chains, was introduced to his outpatient 4-hour hemodialysis regimen with an increase in treatment frequency to 4 sessions per week. Following 6 weeks of dialysis with the HCO dialyzer, serum levels of free κ light chains declined by more than 75%. Concurrently, he recovered kidney function and discontinued dialysis. He subsequently received a successful autologous stem-cell transplant. We discuss the potential merit of using the HCO dialyzer late in the course of the care of patients with myeloma cast nephropathy who are dialysis dependent.