Giant lymph node hyperplasia (castleman's disease) with spontaneous production of high levels of b‐cell differentiation factor activity

A 13‐year‐old girl presented with general fatigue, back pain, anemia, hyperimmunoglobulinemia, and a mediastinal mass on chest radiograph. A mass was surgically removed, and its histologic examination determined the diagnosis of giant lymph node hyperplasia (Castleman's disease). With removal of the hyperplastic lymph node, the clinical symptoms soon disappeared and the abnormal laboratory findings were markedly improved within 1 month: serum IgG levels decreased from 4350 mg/dl to 1829 mg/dl. Immunostaining on the lymph node sections revealed polyclonal B‐lymphocyte and T‐lymphocyte populations. The patient's lymph node cells were cultured without any mitogenic stimulation, and the culture supernatants were assayed for their B‐cell differentiation factor (BCDF) activity to induce IgG production by our Epstein‐Barr virus‐transformed cell line. The patient's lymph node cells produced high levels of BCDF activity: the supernatants could increase the IgG production from 140 ng/ml to 410 ng/ml when the values became from 140 ng/ml to 142 ng/ml or 148 ng/ml with those of the control lymph node cells. These results suggest that the hyperimmunoglobulinemia and its prompt improvement with removal of the hyperplastic lymph node may have been related to the spontaneous production of high levels of BCDF activity by the lymph node cells in the patient.