Waldenström's macroglobulinemia: The role of hospital transfusion medicine laboratory in the diagnosis and management.

Waldenström's macroglobulinemia (WM), a chronic lymphoproliferative disease can cause diverse symptoms due to immunoglobulin M (IgM) paraprotein, cold agglutinins and cryoglobulins. The sample of 59-year-old patient was received for pretransfusion testing in view of spontaneous bleeding from the nose. The samples were mucoid and jelled at room temperature [Figure 1]. Blood grouping showed group III discrepancy, suggesting increased plasma proteins and was resolved by incubating the sample at 37°C. Direct antiglobulin test and cold agglutinin test were negative. Mixed field reaction was observed on cross-match by column agglutination technique [Figure 2]. Serum electrophoresis showed M band in the gamma region with IgM levels above 7286 mg/dL [Figure 3]. Cryoglobulins tested positive and were suspected to be the culprit for the grouping discrepancy and incompatible crossmatch. Bone marrow biopsy findings suggested WM. Patient had symptoms of hyperviscosity, requiring two therapeutic plasma exchange (TPE) procedures [Figures 4 and 5]. As per American Society for Apheresis guidelines, there is no uniform consensus regarding the preferred exchange volume for treatment of hyperviscosity.[1] It is understood that viscosity falls rapidly as M protein is removed, thus relatively small exchange volumes are effective. There was 82% reduction in the IgM level after the first TPE and 88% reduction after the second TPE. There was a dramatic improvement in the symptoms of the hyperviscosity because even small reduction in IgM has a significant effect on lowering serum viscosity. Transient increases in IgM levels after single-agent rituximab therapy occurs in 30–70% of WM patients.[234] Hence, it is recommended that TPE be carried out in advance of rituximab therapy if serum viscosity is more than 3.5 cp, or IgM level is >5000 mg/dL.[5]

Figure 1

The mucoid appearance of the blood sample

Figure 2

Cross-matching showing mixed field reaction

Figure 3

“M” band on serum electrophoresis

Figure 4

Changes in the laboratory parameter following therapeutic plasma

Figure 5

Equipment used for the therapeutic plasma exchange

Resolving grouping discrepancies and incompatible cross-matches are important. The present case illustrates the role of transfusion medicine laboratory in the diagnosis and management of patient with WM.