Intravenous immunoglobulins for neonatal alloimmune neutropenia refractory to recombinant human granulocyte colony-stimulating factor.

Neonatal alloimmune neutropenia (NAN) results from neutrophil destruction by transplacental maternal neutrophil-specific immunoglobulin G (IgG) antibodies directed against the antigen inherited from the father. Treatment is usually based on recombinant human granulocyte colony-stimulating factor (G-CSF) and prevention or treatment of infection. We report the case of neutropenia in a newborn discovered because of fetomaternal infection. The bone marrow biopsy showed normal cellularity. Granulocyte typing, granulocyte cross-matching, and serum assays showed anti-neutrophil antibodies specific for human neutrophil antigen-1c, an antigen rarely involved in this disease. This NAN was refractory to G-CSF but responded to intravenous immunoglobulin (IVIG). IVIG should be considered as a second-line treatment in NAN refractory to G-CSF. Clinical trials, however, are required to define the optimal management of NAN, a rare but probably underestimated life-threatening situation for newborns.

Intrasinusoidal bone marrow infiltration: a common growth pattern for different lymphoma subtypes.

We report a retrospective immunohistochemical study on bone marrow biopsies of 43 patients with different types of lymphomas showing unusual intrasinusoidal infiltration. Most of these patients presented with splenomegaly (74.4%) and peripheral lymphocytosis (83%). In 20/43 patients, lymphoid infiltrates were not detectable on haematoxylin-eosin sections. After immunohistochemistry on bone marrow biopsies and blood and bone marrow smear examinations, the following diagnoses were made: splenic marginal zone lymphoma with villous lymphocytes (SLVL) in 24 patients, large granular lymphocyte (LGL) leukaemia in 14 patients, hepatosplenic T-cell lymphoma in two patients, anaplastic large cell lymphoma in two patients and intravascular large B-cell lymphoma in one patient. In the presence of intrasinusoidal infiltrates of small lymphocytes, a B-cell phenotype (CD20+, CD76/DBA44+/-) was associated with splenic marginal zone lymphoma whereas intrasinusoidal CD3/CD45RA-positive T-cell infiltrates were strongly suggestive of LGL leukaemia. Intrasinusoidal bone marrow infiltration appears to be a common feature of distinct lymphoma subtypes. Immunohistochemical analysis is essential to detect intrasinusoidal medullary infiltrates (which may be minimal) and should be systematically performed in patients with splenomegaly and peripheral lymphocytosis.

Spontaneous secretion of immunoglobulins and anti-HIV-1 antibodies by in vivo activated B lymphocytes from HIV-1-infected subjects: monocyte and natural killer cell requirement for in vitro terminal differentiation into plasma cells.

Peripheral blood mononuclear cells from HIV-1-infected subjects secrete spontaneously in vitro immunoglobulins (Ig) and anti-HIV-1 antibodies (Ab). Purified B lymphocytes secrete only minute amounts of Ig and anti-HIV-1 Ab compared with unfractionated cells. Monocytes and natural killer cells enhanced both secretions by cell-to-cell contacts, involving adhesion and CD27, CD80 costimulatory molecules and IL-6. Cell interactions prolonged the survival and allowed the terminal maturation of in vivo activated B cells. The secreting cell precursors were highly differentiated B cells expressing a broad diversity of maturation markers (CD27(+), CD38(+), CD20(+/-), CD37(+/-), CD71(+/-), HLA-DQ(+/-), sIg(+/-)) but not sIgD, CD28, or CD40. This phenotype and the cytologic aspect of purified B cells suggest that these cells are early plasma cells originated from germinal center. Ex vivo secreting peripheral B cells had probably gone beyond the CD40/CD40 ligand interaction; then following CD28/CD80 and CD27/CD27 ligand (CD70) interactions in the presence of IL-6, they achieved in vitro their differentiation into plasma cells.