[Gammopathies of indeterminant significance and osteoporosis: association or coincidence?].
OBJECTIVE
Osteoporosis is common in subjects over 70 years of age. Likewise, the incidence of monogammapathies of undetermined signification (MGUS) increases with age. We conducted this study to determine whether the biological and histomorphometric characteristics of osteoporosis in patients with MGUS are different from those in primary osteoporosis and to ascertain whether any cause and effect relationships could exist between MGUS and osteoporosis, excluding signs of active myeloma.


METHODS
Serum and urinary phosphorus and calcium, histomorphometric measurements, hormone levels and serum cytokines (IL1, IL6 and TNF alpha) were determined in 7 patients (mean age 71.8 years, 2 men and 5 women) with MGUS associated with osteoporosis with vertebral fractures (OP) and compared with those in 7 osteoporosis patients without MGUS matched for age, sex, and osteoporosis severity and 7 other age and sex matched patients with MGUS without OS. The MGUS + PS patients were followed for 9 years (4.5 to 20) so slowly progressive myeloma could be excluded.


RESULTS
Cytokine levels were the same in the three groups of patients but MGUS + OP patients had higher urinary calcium levels (ca/cr = 0.21 +/- 0.08 vs 0.12 +/- 0.1 (OP) and 0.13 (MGUS); p = 0.04), decreased osteocalcin levels (7 +/- 4.6 ng/ml vs. 12 +/- 4 (OP) and 11.5 +/- 5 (MGUS); p = 0.01) and increased surface resorption (8 +/- 1.4 vs. 3.6 +/- 1.2 (OP) and 5.5 +/- 1.7 (MGUS); p = 0.05).


CONCLUSIONS
It has been demonstrated that MGUS in patients with increased resorption and lower osteocalcin levels frequently progresses to active myeloma. The question is raised as to whether, in certain cases of MGUS, in situ stimulation of bone cells by monoclonal plasma cells could exist without ongoing transformation to active myeloma.
Service de Rhumatologie, CHU Rangueil, Toulouse.
M
M
Laroche
Y
Y
Rolland
J
J
Tackzuck
A
A
Constantin
J P
JP
Salles
B
B
Mazières
D000368:Aged; D001853:Bone Marrow / Q000473:pathology; D001862:Bone Resorption / Q000473:pathology; D002118:Calcium / Q000097:blood / Q000652:urine; D016022:Case-Control Studies; D003404:Creatinine / Q000097:blood / Q000652:urine; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006942:Hypergammaglobulinemia / Q000097:blood / Q000150:complications* / Q000652:urine; D015994:Incidence; D007375:Interleukin-1 / Q000097:blood / Q000652:urine; D015850:Interleukin-6 / Q000097:blood / Q000652:urine; D008297:Male; D015675:Osteocalcin / Q000097:blood / Q000652:urine; D010024:Osteoporosis / Q000097:blood / Q000150:complications* / Q000473:pathology / Q000652:urine; D010281:Parathyroid Hormone / Q000097:blood / Q000652:urine; D010758:Phosphorus / Q000097:blood / Q000652:urine; D010950:Plasma Cells / Q000473:pathology; D016103:Spinal Fractures / Q000097:blood / Q000150:complications / Q000652:urine; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000652:urine
D007375:Interleukin-1; D015850:Interleukin-6; D010281:Parathyroid Hormone; D014409:Tumor Necrosis Factor-alpha; D015675:Osteocalcin; D010758:Phosphorus; D003404:Creatinine; D002118:Calcium
Gammapathie de signification indéterminée et ostéoporose: association ou coïncidence?