DETECTION OF BONE MARROW B-CELL CLONALITY IN DIFFUSE LARGE B-CELL LYMPHOMA

Bone marrow involvement in diffuse large B-cell lymphoma (B-LCL) is one of the factors determining an unfavorable prognosis in standard and intense therapies. Involvement of the bone marrow is detected by histological studies of trephine biopsy specimens. According to some data, molecular studies of the bone marrow in verification of the diagnosis detect up to 25% additional cases of bone marrow involvement in diffuse B-LCL. Bone marrow B-cell clonality was studied in 103 patients with diffuse B-LCL, treated by different intense protocols. Bone marrow B-cell clonality was detected in 26 (25%) patients. Histological studies of trephine biopsy specimens confirmed the bone marrow involvement in lymphoma in only 14 (54%) of 26 patients. Additional immunohistochemical study (CD20 staining) confirmed 6 more cases with bone marrow involvement in the patients with B-cell clonality. O Multifactorial analysis showed that only B-cell clonality in the bone marrow was an independent predictor of a poor response in the studied cohort of patients. Overall and relapse-free survival in the groups with and without bone marrow involvement, confirmed by molecular studies, were 55 and 88%, 58 and 90%, respectively (p<0.05) during a period of 22 months. Detection of B-cell clonality was an independent factor of unfavorable prognosis in intensive care, in contrast to such factors as MPI, molecular type of diffuse B-LCL. Addition of evaluation of bone marrow B-cell clonality to the protocol for primary verification of diffuse B-LCL is discussed.