[Predictive Value of Newly Diagnosed IgG Level in Patients with IgG-type Multiple Myeloma after Initial Treatment]

To explore the predictive value of newly diagnosed IgG levels in the recurrence of IgG-type multiple myeloma (MM) patients after initial treatment.

The clinical and pathological data of 91 patients newly diagnosed IgG-type MM who were hospitalized in the Department of Hematology of the Second People's Hospital of Yichang and Department of Oncology of The Affiliated Hospital of Jianghan University from April 2010 to March 2019 were collected. According to the median IgG level at the time of initial diagnosis, patients were divided into high IgG group and low IgG group. The recurrence time after initial treatment was followed up, and the correlation between newly diagnosed IgG level and recurrence was analyzed by univariate and multivariate analysis, as well as the influencing factors of IgG levels in order to predict furtherly the potential mechanism of recurrence.

Univariate survival analysis showed that high revised international staging system (R-ISS) staging, high level of bone marrow plasma cell (BMPC), lactate dehydrogenase (LDH), creatinine, β₂-microglobulin, and IgG, low level of hemoglobin and serum albumin, high-risk genetic risk, autologous hematopoietic stem cell transplantation (ASCT) were closely related to shortened recurrence time after initial treatment (all P<0.05). COX multivariate survival analysis showed that high R-ISS staging, high level of BMPC, β₂-microglobulin, LDH, and IgG, low level of serum albumin, high-risk genetic risk, ASCT were independently associated with shorter recurrence time after initial treatment (all P<0.05). The median recurrence time of IgG MM patients with high and low IgG level was 30 (7-53) months and 42 (5-65) months, respectively. The cumulative recurrence rate of MM patients with high IgG level was significantly higher than that of patients with low level (χ²=7.982, P=0.005). Univariate analysis of the difference in IgG levels showed that high level of BMPC, urea nitrogen, blood creatinine, and low level of hemoglobin and serum albumin were closely related to high IgG level of IgG-type MM patients in initial diagnosis (all P<0.05). The logistic regression analysis of the differences in IgG levels showed that low level of serum albumin were independently correlated with high IgG levels in IgG-type MM patients in initial diagnosis (P<0.05).

The higher the serum IgG concentration of IgG-type MM patients at first diagnosis, the earlier the recurrence, which is related to the low level of serum albumin, and can be used as a potential recurrence predictor after complete remission of IgG-type MM patients.