Síndrome de Schnitzler: descripción de 3 casos / Schnitzler syndrome: report of 3 cases

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The effect of paraprotein on platelet aggregation.

BACKGROUND: Some patients with paraproteinemia have platelet aggregation disorders and the aim of this study was to examine disturbance of platelet aggregation in healthy blood donors by isolated paraprotein in vitro. METHODS: Using Rivanol, paraprotein was separated from the serum of ten patients with paraproteinemia, who had decreased platelet aggregation with several inducers. Platelet aggregation in ten healthy donors was measured with and without addition of the isolated induced paraprotein. The test was repeated with added human immunoglobulins for intravenous use. RESULTS: Average of maximal levels of platelet aggregation has been significantly decreased in plasma rich in platelets (PRP) of healthy donors after addition of paraprotein when inducers are used: adenosine diphosphate (ADP) (P = 0.007), collagen (COL) (P = 0.008), ristocetin (RIS) (P = 0.001), and epinephrine (EPI) (P = 0.002). Average of latent time of platelet aggregation was significantly prolonged in healthy donors after addition of paraprotein with inducers: COL (P = 0.008), RIS (P = 0.008) and EPI (P = 0.006) while addition of human immunoglobulins caused no change in platelet aggregation. In comparison, when human immunoglobulins were added, maximal platelet aggregation and latent time did not change significantly. Paraprotein isolated from patients with paraproteinamia, who had decrease platelet aggregation, had significantly decreased platelet aggregation when added to PRP of healthy donors, in vitro. CONCLUSION: Platelet aggregation was not significantly changed was confirmed with addition of human immunoglobulins.

Waldenström's macroglobulinemia with an IgM paraprotein that is both a cold agglutinin and a cryoglobulin and has a suppressive effect on progenitor cell growth.

BACKGROUND: A patient with Waldenström's macroglobulinemia was admitted to the hospital with fever, leg pain, and dyspnea. The patient had gas gangrene of the left leg that required above-the-knee amputation. Plasmapheresis was instituted to treat hyperviscosity. STUDY DESIGN AND METHODS: The patient's serum contained an IgM-kappa paraprotein, a cryoglobulin, and a cold agglutinin. The serum was studied. RESULTS: The patient's red cells typed as A1, Rh-positive. The direct antiglobulin test was negative. The serum contained a cold agglutinin with anti-Pr cold agglutinin specificity (titer 4096). Maximal thermal range was 30 degrees C. Following dithiothreitol treatment, the cold agglutinin activity disappeared. The serum IgM concentration in the tested sample was 62.3 g per L. The cold agglutinin titer in the supernatant after removal of the cryoglobulin was 256, and the IgM level was 0.31 g per L. Redissolving the cryoglobulin in a equivalent volume of saline resulted in a cold agglutinin titer of 4096 and an IgM level of 68.4 g per L. These results indicate that the cryoglobulin and the cold agglutinin are the same paraprotein. Serum protein electrophoresis using agarose gel and immunofixation of the serum revealed an IgM-kappa monoclonal band. Progenitor cell assays were performed by adding the patient's serum at final concentrations of 0, 1, 5 and 10 percent (vol/vol) to patient's and normal donor's peripheral blood mononuclear cells. Inhibition of burst-forming units-erythroid and colony-forming units-granulocyte/macrophage by the patient's serum was demonstrated. Appropriate controls and the use of the serum of another patient with Waldenström's macroglobulinemia did not suppress progenitor cell growth. The patient's serum inhibited colony formation in a dose-response fashion. CONCLUSION: Reports of cryoprecipitable cold agglutinins are rare. This case is unusual because the IgM-kappa paraprotein was also a cold agglutinin with anti-Pr specificity and erythroid and granulocyte-macrophage progenitor cell-suppressive properties.

Paraproteinaemias and platelet aggregation: role of whole blood aggregometry.

Whole blood and optical platelet aggregation were measured in normals and in patients with paraproteinaemias; extent of aggregation was correlated with paraprotein concentrations in patients and in normals after addition of different doses of paraproteins; threshold aggregating concentrations of several agonists were also determined in whole blood and in PRP from both groups of subjects. The results indicate that patients with macromolecular monoclonal component bear a "hyperaggregable" state which can be probably ascribed also to plasma hyperviscosity and which is better detected with the impedance aggregometer.

IgA paraprotein inhibition of human neutrophil chemotaxis. Reduced activity following treatment with IgA-specific protease from Neisseria gonorrhoeae.

Removal of the Fc region of human IgA m components by treatment with IgA-specific protease from Neisseria gonorrhoeae reduces the neutrophil chemotactic inhibitory activity associated with IgA M components. This observation, along with the failure of an IgA halfmer paraprotein to inhibit neutrophil chemotaxis, emphasizes the importance of the IgA Fc region in the inhibition of neutrophil chemotaxis by IgA M components.