Abstract
We report a case study of a boy, aged 1 year and 7 months, with a reduced level of CD20 antigen in B cell malignant lymphoma, especially during clinical manifestations and immunological findings. Malignant cells, namely giant atypical lymphoid cells from the abdominal tumor, resembled matured B cells without CD20 antigen ; positive CD79a, negative CD20, CD3 and CD99. A surface marker analysis of 3days' culture of malignant cells also showed reactivity for CD10, CD19, CD21, surface immunoglobulin and HLA-DR with low reactivity for CD20. Ligation of CD20 with monoclonal antibody failed to induce apoptosis in the tumor cells. The lymphoma cells exhibited invasive and destructive features : bone destruction at recorded, apparent central nerve system invasion under intrathecal treatment, reflecting considerable disease activity and rapid growth rate of the malignant cells. The patient showed long-term bone marrow hypoplasia after remission induction chemotherapy along with recurrent varicella-zoster virus infection. He was unsuccessfully treated and expired due to DIC and bronchopneumonia. A B cell malignant lymphoma with a negative or low presence of CD20 such as in our case was likely to be invasive and highly pervasive, and its clinical features suggest a poor prognosis for the patient.
