OBJECTIVETo study the humoral immunity reconstitution and its relationship with infection in patients with multiple myeloma (MM) after undergoing autologous hematopoietic stem cell transplantation (auto-HSCT).

METHODSForty-two MM patients undergoing auto-HSCT were included in this study. Peripheral blood were obtained for immunoglobulin detection, including IgG, IgA and IgM before transplantation and 1, 3, 6, 12, 18 and 24 months after transplantation. The time, type, pathogen of infection between 1 and 24 month after transplantation were analyzed.

RESULTSThe level of IgA at 6 month [(0.75±0.59) g/L] after auto-HSCT was lower than that of pre-auto-HSCT [(1.04±0.70) g/L], and reached the level of pre-auto-HSCT at 9 months [(0.99±0.52) g/L] after auto-HSCT. The level of IgM reached the level of pre-auto-HSCT [(0.45±0.26) g/L] at 3 months after auto-ASCT [(0.50±0.26) g/L]. The level of IgG reached the level of pre-auto-HSCT [(9.80±2.98) g/L] at 1 month after auto-HSCT [(11.09±2.69) g/L], and higher than that of pre-auto-HSCT at 9 months after auto-HSCT [(12.07±3.57) g/L]. The level of IgG with IgG-type MM was higher than that of patients with light-chain type and IgD-type MM at 6, 9 and 12 months after auto-HSCT. The IgA level of patients who obtained complete remission (CR) is much higher than that of patients who obtained nCR in IgG-type patients. The incidence of infection in 6 month after auto-HSCT was higher than that of (6-12) month and >12 month after auto-HSCT. The incidence of infection was strongly negative correlated with IgA (r =-0.943, P=0.005) and IgG (r=-0.943, P=0.005) level. The frequency of viral infection was also negatively correlated with IgA and IgG.

CONCLUSIONThe reconstitution time of IgG, IgA and IgM was different in MM patients after auto-HSCT. IgG recovered first, then IgM, and IgM the last. The incidence of infection was negatively correlated with IgA and IgG. With the recovery of IgG and IgA, the incidence of infection was decreased accordingly.