Korean J Clin Pathol.  1997 Apr;17(2):209-217.

Usefulness of plasma interleukin-6 and C-reactive protein levels in differential diagnosis of clonal and reactive thrombocytosis

• Huh JW
• Chi HS

Abstract

BACKGROUND: The differential diagnosis of clonal and reactive thrombocytosis is clinically relevant because course and treatment are different between them. Several clinical assessments and laboratory tests (degree of such as splenomegaly, duration and degree of thrombocytosis, bone marrow study, cytogenetic study, and platelet function test) are less discriminative, invasive and not commonly available. Therefore, a well discriminative, simple and convenient diagnositic assay is needed. Recently animal experiments demonstrated that recombinant IL-6 administration increased platelets counts by stimulating megakaryocyte maturation and increased hepatic CRP synthesis. So, in this study, we evaluated the usefulness of measurements of IL-6 and CRP levels to distinguish reactive thrombocytosis from clonal thrombocytosis.
METHODS
Included in this study were 88 patients with marked thromobocytosis (>600 x10(9)/L) at Asan Medical Center between September, 1995 and March, 1996. The cause of thrombocytosis was determined by reviewing the medical histories. Sixteen patients had clonal thrombocytosis and 72 patients had reactive thrombocytosis. IL-6 was measured by ELISA (Quantikine(TM), R&D system, Inc., Minneapolis, USA) and CRP was assayed by rate immunonephelometry (Array 360 system, Beckman Instruments Inc., USA).
RESULTS
The patients with reactive thrombocytosis had significantly higher plasma levels of IL-6 and CRP than patients with clonal thrombocytosis (p<0.01, p<0.001). In 98.6% (71/72) of the patients with reactive thromobocytosis, levels of either IL-6 or CRP were elevated, and 43.8% (7/16) of the patients with clonal thrombocytosis had both IL-6 and CRP in normal range. Of 9 patients with clonal thrombocytosis (56.2%) whose levels of either IL-6 or CRP increased, 7 patients had concomitant acute phase reaction such as infection or post operative status. There was significant correlation between IL-6 and CRP levels (r2=0.4, p<0.0001).
CONCLUSION
Elevated levels of either IL-6 or CRP were consistent with reactive thrombocytosis and normal ranges of those suggested clonal thrombocytosis. So measurement of plasma IL-6 and CRP levels is a useful marker for differential diagnosis of clonal and reactive thrombocytosis. For the patients with clonal thrombocytosis who had concomitant acute phase reaction, serial measurements are recommended.

MeSH Terms

Acute-Phase Reaction
Animal Experimentation
Blood Platelets
Bone Marrow
C-Reactive Protein*
Chungcheongnam-do
Cytogenetics
Diagnosis, Differential*
Enzyme-Linked Immunosorbent Assay
Humans
Interleukin-6*
Megakaryocytes
Plasma*
Reference Values
Splenomegaly
Thrombocytosis*
C-Reactive Protein
Interleukin-6