Non-invasive monitoring associated with B lymphoma cells in post-transplant lymphoproliferative disorder (PTLD) patients: Systematic review

BACKGROUND

One of the most severe side effects of solid-organ transplantation is posttransplant lymphoproliferative disease (PTLD). People with human immunodeficiency virus infection (HIV), an immunosuppressive disease comparable to HIV, have a higher chance of developing lymphoma when their peripheral blood contains elevated levels of the immunoglobulins kappa and lambda free light chains (FLCs).

METHODS

This systematic review's objective was to monitor associated B lymphoma cells in PTLD patients. In order to find relevant studies published between 1/1/2000 and 1/9/2022, two independent researchers conducted searches (MT, AJ). A literature search of English language publications was conducted using MEDLINE through PubMed, EMBASETM through Ovid, the Cochrane Library, and Trip. In addition to Magiran and SID, we searched KoreaMed and LILACS for literature published in other languages. sFLC or PTLD, transplant, or Electrophoresis are terms used in the search strategy.

RESULTS

A total of 174 studies were selected. After analyzing their correspondence with the required criteria, a final review of five studies was conducted. The manuscript presents current findings on the potential benefits of the clinical applicability of sFLCs in PTLD. While the preliminary results appear promising, the only consistent result is that early-onset PTLD is predicted within the first two years after transplant, a biomarker that could be used to diagnose the condition.

CONCLUSIONS

Therefore, PTLD has been predicted by using the sFLCs. There have been contradictory results to date. Future research could include assessing the quantity of sFLCs and their quality in transplant recipients. In addition to PTLD and complications after transplantation, sFLCs may provide insight into other diseases. To confirm the validity of sFLCs, more studies are needed.

Early Dynamics and Depth of Response in Multiple Myeloma Patients Treated With BCMA CAR-T Cells

Chimeric antigen receptor T-cell (CAR-T) therapy targeted against B-cell maturation antigen (BCMA) in multiple myeloma (MM) has produced rapid responses but many eventually relapse. In light of this new treatment, novel predictors of progression-free survival (PFS) are needed. We performed a single institution analysis of 54 BCMA-CAR-T patients. We analyzed patient’s overall response rate (ORR) by the IMWG criteria, involved serum-free light chains (iFLC), and minimal residual disease testing by next-generation sequencing (MRD-NGS). Between patients who achieved a ≤SD and those who achieved a ≥PR, PFS differed significantly (p < 0.0001); though there was no difference between patients who achieved a ≥CR vs. VGPR/PR (p = 0.2). In contrast, patients who achieved a nonelevated iFLC at 15 days (p < 0.0001, HR = 6.8; 95% CI, 2.7–17.3) or 30 days (p < 0.001, HR = 16.7; 95% CI, 3.9–71.7) had a prolonged PFS compared with those with an elevated iFLC. Patients achieving MRD-NGS less than the detectable limit at a sensitivity of 10⁻⁶ had a better PFS than those with detectable disease at 1 month (p = 0.02) and 3 months (p = 0.02). In conclusion, achieving a nonelevated iFLC and an undetectable MRD-NGS quickly were factors that were strongly associated with improved PFS. Further studies are needed to confirm the role of these markers in MM patients receiving CAR-T therapies.

Audit of the Prevalence of Noncorrelation of Immunofixation with Protein Electrophoresis and Serum Free Light Chain Assays in Multiple Myeloma in a Tertiary Cancer Care Center

Multiple myeloma (MM) is diagnosed and monitored by correlating panel of test results including serum Protein electrophoresis (SPE), Immunofixation electrophoresis (IFE), serum Free Light chain (sFLC) measurements. This audit is aimed to evaluate the prevalence of non-correlation and discrepancies amongst the three investigations (SPE/IFE/sFLC) for assessment of MM. 106 MM patients were reviewed over 16 months in a tertiary cancer care center by the availability of 3 serum test results (SPE/IFE/sFLC). Patients were divided into 2 groups: group1, newly diagnosed MM patients who were yet to receive myeloma specific treatment (n = 48); and group2, already diagnosed MM patients on treatment and followup (n = 58). Treatment modalities included stem cell transplantation and standard chemotherapy regimens. Non-correlation between the three test results (IFE/SPE/sFLC) was observed (21% in group1 and 45% in group2). Three types of discrepancies were detected as follows: (a) IFE showing less number of restriction bands as compared to SPE (8.6% patients in group2); (b) SPE/IFE negative with an abnormal sFLC ratio (12.5% patients in group1 and 13.7% in group2); (c) SPE/IFE positive but normal sFLC ratio (8% in group1 and 22% in group2). To conclude, IFE may sometimes provide information that does not always correlate with either of the SPE or sFLC results due to different sensitivities, antigen-antibody interactions, or treatment. Hence, SPE plus sFLC may be more useful particularly for patients on follow-up while IFE plus sFLC may help screen the new patients. The judicious selection of the biochemical assays can effectively reduce the treatment cost in a developing country like India.

Laboratory assessment of multiple myeloma

Laboratory testing plays an essential role in the diagnosis and management of patients with multiple myeloma. A variety of chemistry and molecular assays are routinely used to monitor patient progress, response to treatment and relapse. Here, we have reviewed current literature and core guidelines on the details of laboratory testing in myeloma-related investigations. This includes the use and value of protein electrophoresis, serum free light chain and cytogenetic testing. Furthermore, we discuss other traditional chemistry assays essential to myeloma investigation, and potential interferences that may arise due to the disease nature of myeloma, that is, the presence of a monoclonal immunoglobulin. Finally, we discuss the importance of communication in protein electrophoresis results, where laboratorians are required to relate clinically relevant myeloma-relevant information to the ordering physician on the background of a complex pattern of serum or urine proteins. Laboratory testing in myeloma-related investigation relies on several traditional chemistry assays. However, we anticipate new tests and technologies to become available in the future with improved analytical sensitivity, as well as improved clinical sensitivity in identifying patients who are at high risk of progression to multiple myeloma.

Serum free light chains in clinical laboratory diagnostics

Monoclonal free light chains (FLCs) are important disease biomarkers in patients with plasma cell-proliferative disorders. The increasing evidence for clonal diversity and evolution in multiple myeloma highlights the importance of laboratory algorithms that measure both intact immunoglobulins and monoclonal FLCs, at diagnosis and when monitoring response to treatment. A particular focus in the field has been on the utility of serum FLC (sFLC) assays to replace urine electrophoresis for monoclonal FLC measurement. Due to the limited sensitivity and practical constraints of urine analysis, a serum-based algorithm of SPE and sFLC has been adopted by many laboratories as a first line screen in patients with suspected monoclonal gammopathies. This review will discuss the data supporting the use of this simple serum-based algorithm at initial diagnosis, including its utility for the rapid identification of monoclonal FLC in the setting of unexplained acute kidney injury, and provide a comprehensive review of the diagnostic sensitivity of sFLC in patients with multiple myeloma, AL amyloidosis and light chain deposition disease.