SARS-CoV-2 infection is not associated with the emergence of monoclonal gammopathies.

BACKGROUND: Upon infection activated plasma cells produce large quantities of antibodies which can lead to the emergence of a monoclonal component (MC), detectable by serum protein electrophoresis (SPEP). This study aims to investigate any correlation between SARS-CoV-2 infection and MC development and, if identified, whether it persists during follow-up. METHODS: SPEPs of 786 patients admitted to hospitals between March 01 2020 and March 31 2022 were evaluated. Positive (SARS-CoV-2+) and negative (SARS-CoV-2-) patients to nasopharyngeal swab for SARS-CoV-2 by RT-PCR were included. The persistence/new occurrence of MC was investigated for all patients during follow-up. Patient groups were compared by chi-square analysis. RESULTS: MC was identified in 12% of all patients admitted to hospital, of which 28.7% were SARS-CoV-2+. The most common immunoglobulin isotype in both groups was IgG-k. There was no correlation between MC development and SARS-CoV-2 infection (p = 0.173). Furthermore, the risk of MC persistence in SARS-CoV-2-negative patients was revealed to be higher than in the SARS-CoV-2+ at follow-up (HR = 0.591, p = 0.05). CONCLUSIONS: Our study suggests that the detection of MC during SARS-CoV-2 infection is most likely due to the hyperstimulation of the humoral immune system, as also occurs in other viral infections.

Prognostic Relevance of Multi-Antigenic Myeloma-Specific T-Cell Assay in Patients with Monoclonal Gammopathies.

Multiple Myeloma (MM) typically originates from underlying precursor conditions, known as Monoclonal Gammopathy of Undetermined Significance (MGUS) and Smoldering Multiple Myeloma (SMM). Validated risk factors, related to the main features of the clonal plasma cells, are employed in the current prognostic models to assess long-term probabilities of progression to MM. In addition, new prognostic immunologic parameters, measuring protective MM-specific T-cell responses, could help to identify patients with shorter time-to-progression. In this report, we described a novel Multi-antigenic Myeloma-specific (MaMs) T-cell assay, based on ELISpot technology, providing simultaneous evaluation of T-cell responses towards ten different MM-associated antigens. When performed during long-term follow-up (mean 28 months) of 33 patients with either MGUS or SMM, such deca-antigenic myeloma-specific immunoassay allowed to significantly distinguish between stable vs. progressive disease (p < 0.001), independently from the Mayo Clinic risk category. Here, we report the first clinical experience showing that a wide (multi-antigen), standardized (irrespective to patients' HLA), MM-specific T-cell assay may routinely be applied, as a promising prognostic tool, during the follow-up of MGUS/SMM patients. Larger studies are needed to improve the antigenic panel and further explore the prognostic value of MaMs test in the risk assessment of patients with monoclonal gammopathies.

Analysis of cryoproteins with a focus on cryofibrinogen: a study on 103 patients.

OBJECTIVES: Cryofibrinogen (CF) is an abnormal protein in plasma that precipitates at 4 °C and dissolves at 37 °C. Whilst serum cryoglobulins (CGs) analysis is common practice, CF investigation is rarely performed. This study aims to describe the testing methodology developed at our laboratory, potential pitfalls for all analytical phases, the distribution among hospital wards and clinical conditions underlying test requests and clinical conditions in which to order CF analysis is useful. METHODS: Retrospective analysis of laboratory samples received between January 2019 and June 2021 with CF testing requests. RESULTS: A complete protocol for CF pre-analytical, analytical and post-analytical phases are supplied. Most test requests were received from the rheumatology department for systemic sclerosis or liver transplant screening. Among the 103 in-patients included, CF+ was confirmed in 68 patients (66%). Of observed CF+ patients (n=68) most cases were CGs- (n=44, 67%). Isolated CF was found in 43% of the cases. Among CF- patients (n=35; 34%) only 2 patients had positive CGs (CGs+). Among rheumatology patients (n=66), isolated CF+ was observed in 45% (n=30/66), whilst among patients with systemic sclerosis with CF+ (n=19), isolated CF+ was detected in 79% (n=15/19). CONCLUSIONS: Described analytical procedures may be used for the creation of harmonized recommendations and indications for CF analysis. Isolated CF positivity among hospitalized patients, predominantly rheumatology and systemic sclerosis patients, appears higher than rates previously reported in literature. We propose CF test recommendations should be included in investigation protocols for diseases where cryofibrinogenemia may occur.