Set - Out - English

oimbra

494

ssoc

ras

2014; 60(5):490-499

The assessment of the clinical status of patients invol-

ves several examinations and laboratory tests (Table 2).

When interpreting the results it is important to con-

sider that some parameters could be altered because the

monoclonal IgM may interfere in several measurements

performed in automated analyzers, especially in the eva-

luation of HDL cholesterol, bilirubin, inorganic phos-

phate, LDL cholesterol, C-reactive protein, creatinine, glu-

cose, urea, iron and calcium ions.

ifferential

diagnosis

It is fundamental to distinguish WM from other disor-

ders that could be clinically confused with this disease.

Differential diagnosis (Table 3) is important for the

exclusion of neoplasms potentially secreting monoclo-

nal IgM and which can also present lymphocytes with

lymphoplasmocytoid differentiation in the bone marrow.

This group includes marginal zone lymphomas,

chro-

nic lymphocytic leukemia (CD5

, CD23

), mantle cell lym-

phoma (CD5

, CD23

), follicular lymphoma (CD10

) and

multiple myeloma (CD138

, CD38

, CD56

17,57

The differentiation between symptomatic WM, asymp-

tomatic WM and IgM monoclonal gammopathy of un-

determined significance (MGUS) is important since the

latter patients present risk of progression to symptoma-

tic WM of 1.5%/year.

58,59

This differs from asymptomatic

Table 2

Laboratory assessment in patients with clinical suspicion of Waldenström’s macroglobulinemia

Laboratory exam

Clinical justification

Electrophoresis of serum proteins

Electrophoresis of urinary proteins (24-hour urine)

Detection of monoclonal gammopathy - homogeneous peak, high, narrow

base, usually in the area of gamma globulins

Immunofixation of serum and urinary proteins

Characterize the immunoglobulin: heavy chain and light chain

Bone marrow biopsy

Assess the bone marrow infiltration by lymphocytes, the infiltration pattern

and cell morphology

Erythrocyte sedimentation rate

Frequently raised

Cytogenetic studies

Differential diagnosis of other malignancies of B-lymphocytes secreting

monoclonal IgM

Blood test

- Reticulocyte count

- Concentration of haptoglobin, indirect bilirubin and lactate dehydrogenase

- Research, identification and quantification of “cold agglutinins”

- Direct Coombs Test and title of “cold agglutinins”

Evaluation of thrombocytopenia and anemia, which is usually normocytic

and normochromic

Search autoimmune hemolytic anemia. Useful in patients with Raynaud’s

syndrome, acrocyanosis or limb ulceration

Serum viscosity

Determine if the patient has signs and symptoms of hyperviscosity or IgM

concentration >4000 mg/dL

Eye examination - ophthalmoscopy

Justified in the event of changes in vision

Urea, creatinine and transaminases (AST and ALT)

Evaluation of renal and hepatic function

2-microglobulin

Relevant for prognosis

IgG and IgA

Predisposition to respiratory infections

TTPa, TP, TT

In patients with bleeding diathesis and a tendency to bruise

Detection and semi-quantification of anti-MAG, anti-SGPG, anti-

GM1, anti-

sulfatide

antibodies

In patients with peripheral neuropathy, such as progressive symmetrical

numbness of the limbs, burning sensation and tingling, pain in the feet and

hands

Screening of AL amyloidosis - electrophoresis and immunofixation

of urinary proteins (24-hour urine)

Confirmation of AL amyloidosis test - abdominal fat aspirate

In suspected cases of AL amyloidosis

Electromyography

In patients who have impaired motor function

Computed tomography of the abdomen, trunk and pelvis

Detection of organomegaly (e.g. spleen, liver) and lymphadenopathy

AST, aspartate aminotransferase; ALT, alanine aminotransferase; APTT, activated partial thromboplastin time; PT, prothrombin time; TT, thrombin time; MAG, myelin-associated glycoprotein;

SGPG, sulfate-3-glucuronyl paragloboside; GM1, GM1 ganglioside.