Challenges With Serum Protein Electrophoresis in Assessing Progression and Clinical Response in Patients With Waldenström Macroglobulinemia

Laboratory Detection and Initial Diagnosis of Monoclonal Gammopathies

CONTEXT.—

The process for identifying patients with monoclonal gammopathies is complex. Initial detection of a monoclonal immunoglobulin protein (M protein) in the serum or urine often requires compilation of analytical data from several areas of the laboratory. The detection of M proteins depends on adequacy of the sample provided, available clinical information, and the laboratory tests used.

OBJECTIVE.—

To develop an evidence-based guideline for the initial laboratory detection of M proteins.

DESIGN.—

To develop evidence-based recommendations, the College of American Pathologists convened a panel of experts in the diagnosis and treatment of monoclonal gammopathies and the laboratory procedures used for the initial detection of M proteins. The panel conducted a systematic literature review to address key questions. Using the Grading of Recommendations Assessment, Development, and Evaluation approach, recommendations were created based on the available evidence, strength of that evidence, and key judgements as defined in the Grading of Recommendations Assessment, Development, and Evaluation Evidence to Decision framework.

RESULTS.—

Nine guideline statements were established to optimize sample selection and testing for the initial detection and quantitative measurement of M proteins used to diagnose monoclonal gammopathies.

CONCLUSIONS.—

This guideline was constructed to harmonize and strengthen the initial detection of an M protein in patients displaying symptoms or laboratory features of a monoclonal gammopathy. It endorses more comprehensive initial testing when there is suspicion of amyloid light chain amyloidosis or neuropathies, such as POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome, associated with an M protein.

Study on the Role of Calreticulin Within Platelet from Adult Patients with Chronic Immune Thrombocytopenic Purpura

To observe the differences in proteins between adult patients with chronic immune thrombocytopenic purpura (ITP) and healthy adults. 30 patients with chronic ITP and 30 healthy controls were enrolled into the study. The platelet total protein was extracted from peripheral venous blood of 10 chronic ITP patients and 10 healthy controls respectively, and subjected to two-dimensional electrophoresis (2-DE) to find the differential protein spot between chronic ITP patients and healthy controls, then the differential protein spots were identified by mass spectrometry. Subsequently, platelets RNA and proteins were isolated from the other 20 chronic ITP patients and 20 healthy controls respectively, and used for confirming the 2-DE and mass spectrometry results by using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and enzyme linked immunosorbent assay (ELISA). 2-DE combined with mass spectrometry revealed that calreticulin (CRT) expressed normally within platelets from healthy controls, while it reduced within platelets from patients with chronic ITP. qPCR and ELISA confirmed that CRT was decreased at both RNA transcription and protein expression levels within platelets from chronic ITP patients compared with healthy controls. Decreased transcription and expression of CRT within platelets may play an important role in the pathogenesis of chronic ITP, which is worthy of further study.

How I treat Waldenström macroglobulinemia

Waldenström macroglobulinemia (WM) is a B-cell neoplasm manifested by the accumulation of clonal immunoglobulin (Ig)M-secreting lymphoplasmacytic cells. MYD88 and CXCR4 warts, hypogammaglobulinemia, infections, myelokathexis syndrome-like somatic mutations are present in >90% and 30% to 35% of WM patients, respectively, and impact disease presentation, treatment outcome, and overall survival. Familial predisposition is common in WM. Asymptomatic patients should be observed. Patients with disease-related hemoglobin <10 g/L, platelets <100 × 10(9)/L, bulky adenopathy and/or organomegaly, symptomatic hyperviscosity, peripheral neuropathy, amyloidosis, cryoglobulinemia, cold-agglutinin disease, or transformed disease should be considered for therapy. Plasmapheresis should be used for patients with symptomatic hyperviscosity and before rituximab for those with high serum IgM levels to preempt a symptomatic IgM flare. Treatment choice should take into account specific goals of therapy, necessity for rapid disease control, risk of treatment-related neuropathy, immunosuppression and secondary malignancies, and planning for future autologous stem cell transplantation. Frontline treatments include rituximab alone or rituximab combined with alkylators (bendamustine and cyclophosphamide), proteasome inhibitors (bortezomib and carfilzomib), nucleoside analogs (fludarabine and cladribine), and ibrutinib. In the salvage setting, an alternative frontline regimen, ibrutinib, everolimus, or stem cell transplantation can be considered. Investigational therapies under development for WM include agents that target MYD88, CXCR4, BCL2, and CD27/CD70 signaling, novel proteasome inhibitors, and chimeric antigen receptor-modified T-cell therapy.