Objective: The study aims to explore the clinical and
biological characteristics of patients with non-
IgM lymphoplasmacytic
lymphoma (LPL) . Methods: The clinical data of 340 patients with LPL admitted to the Institute of Hematology &
Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College were collected retrospectively, including 23 cases of the non-
IgM LPL and 317 cases of the Waldenström's
macroglobulinemia (WM) , from July 1993 to August 2020. The clinical and
biological characteristics of the two groups were compared. Results: Among 23 patients with the non-
IgM type LPL, two patients secreted monoclonal
IgA, 14 patients secreted monoclonal
IgG, and seven patients did not secrete monoclonal
immunoglobulin. The median age of the non-
IgM LPL and WM were both 62 (35-81) years old. Compared with the WM group, the proportion of women (56.5% vs 27.3%, P=0.007) , the proportion of
splenomegaly (60.1% vs 43.8%, P=0.100) , and the proportion of extranodal invasion (21.7% vs 12.3%, P=0.672) in non-
IgM LPL group were higher. Eighteen patients were tested for MYD88 gene mutation, and the overall mutation rate of MYD88 was 55.6%. In the non-
IgM LPL group, a total of 17 patients received treatment, which had a comparable proportion (94.4% vs 92.7%, P=0.488) to the WM group. Sixteen patients were evaluated for efficacy, and the overall remission rate of the first-line treatment was 87.5%. The median follow-up time was 33.9 (3.5-125.1) months, and the median PFS and OS were both not reached. The 3-year PFS and OS rates were 71.4% and 68.9%, respectively. In the WM group, the median PFS was 66.2 months and the median OS was 78.1 months. Compared with the WM group, in the non-
IgM group no significant differences in PFS (P=0.340) and OS (P=0.544) were seen. Conclusion: The clinical and
biological characteristics of the non-
IgM LPL and WM patients were similar. However, the proportion of women and extranodal involvement were higher in the non-
IgM LPL group. The survival and prognosis of the non-
IgM LPL patients were similar to those of the WM patients.