Salvage therapy of refractory hemophagocytic lymphohistiocytosis with alemtuzumab.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome that remains difficult to treat. Even with current standard HLH therapy, only approximately half of patients will experience complete resolution of disease, and early mortality remains a significant problem. Salvage therapies have been described only in limited case reports, and there are no large studies of second-line therapies. PROCEDURE: We reviewed the charts of 22 pediatric and adult patients who received alemtuzumab for the treatment of refractory HLH at our center or in consultation with our group. RESULTS: Patients had received conventional therapies for a median of 8 weeks (range: 2-70) prior to alemtuzumab, and treatment immediately prior to alemtuzumab included dexamethasone (100%), etoposide (77%), cyclosporine (36%), intrathecal hydrocortisone ± methotrexate (23%), methylprednisolone (9%), and rituximab (14%). Patients received a median dose of 1 mg/kg alemtuzumab (range: 0.1-8.9 mg/kg) divided over a median of 4 days (range: 2-10). Fourteen patients experienced an overall partial response, defined as at least a 25% improvement in two or more quantifiable symptoms or laboratory markers of HLH 2 weeks following alemtuzumab (64%). Five additional patients had a 25% or greater improvement in a single quantifiable symptom or laboratory marker of HLH (23%). Seventy-seven percent of patients survived to undergo allogeneic hematopoietic cell transplantation. Patients experienced an acceptable spectrum of complications, including CMV and adenovirus viremia. CONCLUSION: Alemtuzumab appears to be an effective salvage agent for refractory HLH, leading to improvement and survival to HCT in many patients. Prospective trials to define optimal dosing levels, schedules, and responses are needed.

Immunophenotype of blood lymphocytes in neuroblastoma-associated opsoclonus-myoclonus.

OBJECTIVE: To determine whether the distribution of peripheral blood mononuclear cells (PBMCs) is altered in paraneoplastic opsoclonus-myoclonus (POM). METHODS: PBMCs from 17 children with POM, 17 children with OM but no tumor, and 17 controls were immunophenotyped using a comprehensive panel of surface markers by dual-laser flow cytometry. All groups were matched for age and gender; POM and OM patients were matched for treatment. RESULTS: In the POM patients, the CD4+ T-cell subset was smaller in both relative size (-18%, P = 0.02) and absolute size (-41%, P = 0.03) compared with controls. The CD4/CD8 ratio also was less (-29% to -44%) and was related to POM duration (P = 0.03). The absolute but not relative size of the gammadelta T-cell subset was reduced (-44%, P = 0.02). There were no significant abnormalities of CD19+ B-cells, CD3- or CD3+ NK cells, HLA-DR+ or CD25+ T-cells, or CD45RA+ or CD45RO+ T-cells. Prior tumor chemotherapy, which was associated with a higher percentage but not number of CD8+ T-cells, did not restore the CD4+ T-cell subset. When the POM and OM groups, which were not significantly different, were combined, chemotherapy decreased both the relative and absolute size of the CD19+ B-cell pool and had small effects on other lymphocyte subsets. CONCLUSIONS: POM is characterized by T-cell abnormalities of PBMCs, the most robust of which is reduction of the CD4+ T-cell subset and the CD4/CD8 ratio. Although this reduction was found previously in cerebrospinal fluid in POM patients, PBMC subsets did not otherwise reflect cerebrospinal fluid abnormalities. Longitudinal studies will be necessary to determine whether PBMC abnormalities could serve as treatment markers.