[In vitro sensitivity of accessory hematopoietic cells from neutropenic subjects to the activity of human gamma-globulin].

We studied eight patients all showing neutropenia: drug-induced isolated neutropenic failure (2 cases), immune cell-mediated neutropenia (2 case), severe bone marrow hypoplasia (2 cases), dysmyelopoietic syndrome (1 case), cyclic neutropenia (1 case). Aim of the study was to assay the effect on CSA production of the pretreatment of autologous peripheral blood mononucleated cells (APBMN) with immunoglobulins (Ig). The CFU-GM growth were tested in different experimental conditions: with standard source of CSA, with autologous source, with autologous source modified by means of the preincubation of the autologous cells with Ig. The bone marrow CFU-GM culture was performed by Pike and Robinson's double layer agar technique. The experimental data were pointed out with topographic lecture of the dishes repeated at two times so as to obtain besides the aggregates global growth their dynamic classes too. We observed that the APBMN cells pretreatment with Ig modulates CSA production: represses it in cases showing high production and increases it in those showing low production. The effect of Ig modulation appears clearer on the GM-progenitor proliferating late (AC-C) than on those proliferating early (AC-A). This effect turned out to be particularly evident in a case with immune cell-mediated neutropenia and in both cases with drug-neutropenia. We retain that the monomers Ig could block Fc receptors and modulate their expression on macrophagic cells, conditioning in this way the CSA production. The parenteral administration of intact Ig (in vivo treatment of the APBMN cells) appears therefore helpful both in cases with CSA defect and in cases with excess of CSA production.(ABSTRACT TRUNCATED AT 250 WORDS)