Background

Serum free light chain (FLC) assay has been used to evaluate the prognosis of several hematologic malignancies. We evaluated the prognostic role of monoclonal gammopathy (MG) and polyclonal gammopathy (PG) measured by serum FLC and immunofixation (IF) in DLBCL.

Patients and methods

We retrospectively reviewed 115 patients with DLBCL who treated with rituximab containing chemotherapy. MG was defined as elevated kappa (κ) or lambda (λ) FLC with abnormal κ to λ ratio or positive IF and PG was defined as elevated κ and/or λ FLC with normal κ to λ ratio and negative IF.

Results

Fifty-six (48.7%) patients had an elevated FLC. Twenty (17.4%) patients had MG and 39 (33.9%) patients accompanied by a PG. Two-year overall survival (OS) was 89.2%, and 2-year event-free survival (EFS) was 88.4%. Elevated FLC was associated with inferior OS and EFS (p=0.013, p=0.012). Patients with MG had an inferior OS and EFS compared to patients with normal FLC (p=0.006, p=0.011). In multivariate analysis, both elevated FLC and MG showed the significance for OS (HR 4.57, 95% CI 1.43-14.60, p=0.001 and HR 5.63, 95% CI 1.50-21.09, p=0.010). Elevated FLC did not show the significantly shorter OS or EFS in non-germinal center B-cell (GCB) type according to the Han’s criteria. However, MG was a significant prognostic factor for OS and EFS in non-GCB type (HR 6.28, 95% CI 1.21-32.62, p=0.029, HR 6.38, 95% CI 1.58-25.74, p=0.009).

Conclusion

It important to evaluate the associated MG and PG using serum FLC and IF for predicting the prognosis of DLBCL, especially in non-GCB subtype.

Table 1

Patients characteristics of monoclonal and polyclonal gammopathy compared to normal FLC

  MG PG Normal FLC  
  n (%) n (%) n (%) p
Age >60 years  13 (11.3)  25 (21.7)  21 (18.3)  0.016  
Male sex  10 (8.7)  21 (18.2)  30 (26.1)  0.956  
ECOG >1  4 (3.5)  5 (4.3)  5 (4.3)  0.379  
Creatinine >UNL  0 (0.0)  4 (3.5)  0 (0.0)  0.028  
Stage III/IV  16 (13.9)  19 (16.5)  21 (18.3)  0.005  
Extranodal >1  10 (8.7)  13 (11.3)  17 (14.8)  0.278  
LDH >UNL  16 (13.9)  21 (18.3)  32 (27.8)  0.126  
IPI HI/H  12 (10.4)  17 (14.8)  19 (16.5)  0.122  
B symptom  9 (7.8)  27 (23.5)  48 (41.7)  0.015  
Non-GCB  11 (9.6)  22 (19.1)  25 (21.7)  0.249  
ALC <1000  7 (6.1)  11 (9.6)  7 (6.1)  0.046  
AMC ≥800  1 (0.9)  2 (1.7)  4 (3.5)  0.999  
  MG PG Normal FLC  
  n (%) n (%) n (%) p
Age >60 years  13 (11.3)  25 (21.7)  21 (18.3)  0.016  
Male sex  10 (8.7)  21 (18.2)  30 (26.1)  0.956  
ECOG >1  4 (3.5)  5 (4.3)  5 (4.3)  0.379  
Creatinine >UNL  0 (0.0)  4 (3.5)  0 (0.0)  0.028  
Stage III/IV  16 (13.9)  19 (16.5)  21 (18.3)  0.005  
Extranodal >1  10 (8.7)  13 (11.3)  17 (14.8)  0.278  
LDH >UNL  16 (13.9)  21 (18.3)  32 (27.8)  0.126  
IPI HI/H  12 (10.4)  17 (14.8)  19 (16.5)  0.122  
B symptom  9 (7.8)  27 (23.5)  48 (41.7)  0.015  
Non-GCB  11 (9.6)  22 (19.1)  25 (21.7)  0.249  
ALC <1000  7 (6.1)  11 (9.6)  7 (6.1)  0.046  
AMC ≥800  1 (0.9)  2 (1.7)  4 (3.5)  0.999  
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Disclosures:

No relevant conflicts of interest to declare.

Topics:
diffuse large b-cell lymphoma, free immunoglobulin light chain, immunofixation, chemotherapy regimen, creatinine, electrocorticogram, extranodal disease, hematologic neoplasms, monoclonal gammopathy of undetermined significance, paraproteinemias

Author notes

*

Asterisk with author names denotes non-ASH members.

© 2013 by The American Society of Hematology
2013
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