Investigating the utility of saliva immunoglobulins for the detection of myeloma and using myeloma proteins to clarify partition between oral and systemic immunity

Abstract

Objectives: Myeloma is characterised by the presence of monoclonal immunoglobulin (M-protein) and the free light chain (FLC) in blood. We investigated whether these Mproteins and FLC are detectable in myeloma patients' saliva to evaluate its utility for non-invasive screening and monitoring of haematological malignancies.Methods: A total of 57 patients with monoclonal gammopathy and 26 age-matched healthy participants provided paired serum and saliva samples for immunoglobulin characterisation and quantification.Results: Myeloma patients had IgG or IgA M-protein levels ranging up to five times and FLC levels up to a thousand times normal levels of polyclonal immunoglobulins.Despite these highly elevated levels, only two IgG and no IgA M-proteins or FLC could be detected in paired saliva samples. Most patients had reduced levels of serum polyclonal immunoglobulins, but all had normal levels of salivary IgA. Conclusions:Immunoglobulin transfer from blood is not determined by levels in the systemic circulation and more likely dictated by periodontal inflammation and the integrity of the oral epithelium. Immunoglobulins secreted by bone marrow plasma cells do not substantially enter saliva, which represents a poor medium for myeloma diagnosis. These findings, along with normal salivary IgA levels despite systemic immunoparesis, support a strong partitioning of oral from systemic humoral immunity.

Personalized Disease Monitoring in Pediatric Onset Multiple Sclerosis Using the Saliva Free Light Chain Test

“…However, there is still no consensus regarding this question. While some studies raise possibility of impaired mucosal barriers in MS ( 28 – 30 ), other reports support a strong partitioning of oral from systemic humoral immunity ( 31 ). Irrespectively of what are the precise mechanisms explaining the saliva FLC level changes in POMS, our study demonstrates the utility of the non-invasive and safe saliva FLC test for monitoring the disease activity in POMS, and, potentially, in other demyelinating diseases.…”

Evaluating serum and salivary free light chains levels as a potential indicator of acute kidney injury post cardiac surgery

“…It is non-intrusive, does not require specialized training or equipment for collection, and may be more cost-effective. As a result, saliva has garnered increased attention as a viable alternative for diagnosing systemic diseases in different medical fields [15][16][17][18][19][20].…”