Prognostic value of circulating plasma cells in monoclonal gammopathy of undetermined significance.
OBJECTIVE
Monoclonal gammopathy of undetermined significance (MGUS) progresses to multiple myeloma or another related plasma cell disorder (PCD) at a rate of approximately 1% per year. Identification of patients with MGUS at high risk of progression will allow development of preventive strategies. We studied the prognostic value of circulating plasma cells (PCs) in patients with MGUS to predict progression.


METHODS
Patients were eligible for this retrospective analysis if they were seen at the Mayo Clinic between 1984 and 1997, were diagnosed with MGUS, and had an analysis of the peripheral blood for circulating PCs by the slide-based immunofluorescence method. Patients were observed for progression to another PCD.


RESULTS
Three hundred twenty-five patients were eligible and 63 (19%) had circulating PCs. Patients with circulating PCs were twice as likely (hazard ratio, 2.1) to experience progression to another PCD (most commonly myeloma), compared with those without circulating PCs (95% CI, 1.1 to 4.3; P = .03). In patients with circulating PCs, the median progression-free survival was 138 months compared with a median not yet reached for those without circulating PCs (P = .028). The median overall survival also was shorter for those with circulating PCs. Other factors with prognostic value were high levels of M protein and non-immunoglobulin G heavy-chain type.


CONCLUSIONS
The presence of circulating PCs, especially when combined with other known prognostic factors such as M protein concentration and immunoglobulin isotype, identify a group of individuals with MGUS at higher risk of progression to overt multiple myeloma.
Kumar
Shaji
S
Department of Internal Medicine, Division of Hematology, Mayo Clinic, Rochester, MN 55905, USA.
Rajkumar
S Vincent
SV
Kyle
Robert A
RA
Lacy
Martha Q
MQ
Dispenzieri
Angela
A
Fonseca
Rafael
R
Lust
John A
JA
Gertz
Morie A
MA
Greipp
Philip R
PR
Witzig
Thomas E
TE
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D007223:Infant; D008297:Male; D009101:Multiple Myeloma / Q000276:immunology*; D009194:Myeloma Proteins / Q000276:immunology; D010265:Paraproteinemias / Q000276:immunology*; D010950:Plasma Cells / Q000276:immunology*; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis
D007075:Immunoglobulin M; D009194:Myeloma Proteins; C085016:multiple myeloma M-proteins