Characteristics of Immunoglobulin Deficiency in Patients with Untreated Multiple Myeloma Stage II and III.

Introduction: It is well known that multiple myeloma (MM) is often associated with immunoglobulin (Ig) deficiency and increased risk of infection. We evaluated the Ig levels in 150 patients with MM stage II and III as part of a phase III randomised study comparing the effectiveness of melphalane and prednisolone versus bendamustine and prednisolone.

Patients and methods: 150 patients at a median age of 68 years, with untreated MM stage II, n = 19, and stage III, n = 131, were evaluated. MM type was IgG, IgA, light chain, and biclonal in 106 (70,7 %), 32 (21,3 %), 11 (7,5 %), 1 (0,7 %) patients respectively. Serum Ig levels were measured in all patients prior to chemotherapy. Normal values for IgG were 7,02 – 14,6 g/l, for IgA 0,24 – 3,81 g/l, and for IgM 0,54 – 2,27 g/l. Only Ig classes other than the myeloma protein class were evaluated.

Results: Patients with IgG MM had a median serum IgA of 0,4 g/l (range 0 – 7,9), and a median IgM level of 0,2 g/l (0 – 5,6). In 106 patients with IgG MM, IgA serum levels were below, within normal, and above normal values in 36 (34 %), 69 (65,1 %), and 1 (0,9 %) patients, respectively. On the other hand, IgM levels in these patients were below, within normal, and above normal values in 94 (88,7 %), 9 (8,5 %), and 3 (2,8 %) patients, respectively. Median IgG for IgA MM patients was 3,7 g/l (range 0,1 – 11,8), and median IgM in these 32 patients was 0,2 g/l (range 0 – 1,3). IgG levels were below and within normal in 28 (87,5 %), 4 (12,5 %) patients, respectively. Similarly, IgM level were below, and within normal range in 30 (93,8 %), and 2 (6,3 %) patients with IgA MM. Lastly, median IgG in patients with light chain myeloma was 6,3 g/l (range 2,1 – 9,7), median IgA, and median IgM were 0,4 g/l (range 0,1 – 1,7), and 0,3 g/l (range 0,1 – 0,8), respectively. IgG, IgA, and IgM were below normal values in 8 (72,7 %), 3 (27,3 %), and 9 (81,8 %), respectively.

Conclusion: Most patients with untreated MM have markedly reduced serum Ig levels. The correlation of reduced Ig level to the incidence of infections is being evaluated. The effect of chemotherapy on Ig levels is currently being assessed in our phase III study.