Neutropenia and thrombocytopenia in infants with Rh hemolytic disease.

To assess the incidence and mechanisms of thrombocytopenia and neutropenia in neonates with Rh hemolytic disease, we studied 20 consecutive patients with this condition who were born at our hospital. All five patients with severe disease (hydrops) had neutropenia and thrombocytopenia before and after exchange transfusions. Two of six patients with moderately severe disease (not hydropic but requiring exchange transfusion) had neutropenia; all six had thrombocytopenia. Of nine patients with mild disease (not treated with exchange transfusions), two had neutropenia but none had thrombocytopenia. The mean platelet volume was low or normal (7.5 +/- 0.2 ft) in the patients with thrombocytopenia, and the neutropenia was not accompanied by a "left shift" (ratio of immature to total neutrophils 0.26 +/- 0.03, mean +/- SEM). In two severely affected patients, erythroid progenitor levels were elevated and their proliferative rates (tritiated thymidine suicide) were increased, whereas their granulocyte-macrophage progenitor levels and the proliferative rates of those progenitors were diminished. In a severely affected patient, the in vitro maturation of multipotent progenitors was altered, with production of a greater than normal proportion of normoblasts (p less than 0.01) but fewer neutrophils (p less than 0.02) and megakaryocytes (p less than 0.03). It appears that the marked increase in erythropoiesis in fetuses with Rh hemolytic disease can be accompanied by a down-modulation of neutrophil and platelet production.

Granulocyte-macrophage progenitor cells in term and preterm neonates.

In groups of adults, and term and preterm neonates, we determined: the blood concentration, the proliferative rate, and the variety of progeny of committed granulocyte-macrophage progenitor cells (CFU-GM). In five of eight term neonates and in all premature infants, a potentially significant limitation of neutrophil production was detected. Unlike the slowly proliferating CFU-GM present in the blood of healthy adult subjects (7% thymidine suicide, range 0% to 32%), the circulating CFU-GM in the premature subjects were proliferating at a near maximal rate (55%, range 40% to 75%, P less than 0.001). Because CFU-GM proliferation is nearly maximal in the baseline, noninfected state, neonates may have restricted ability to increase neutrophil production from CFU-GM during times of increased neutrophil need, such as during bacterial infection. Such inability may predispose neonates to exhaustion of the neutrophil supply during bacterial infection.

Evoluçäo do carcinoma mamário: novos parâmetros imunopatológicos de avaliaçäo; estudo experimental em camundongos (MuMT), I - Hematopoiese esplênica / Course of mammary carcinoma: new immunopathological parameters of evaluation; experimental study in mice (MuMT), T-Splenic hematopoiesis

Foram identificadas e contadas especificamente colônias das diferentes linhagens hematopoiéticas no baço. Grupo controle - Trinta camundongos normais constituiram os parâmetros normais. Grupo experimental - Duzentos camundongos foram inoculados intraperitonealmente com MuMT e sacrificados diariamente em sub-grupos de dez, abrangendo toda a evoluçäo da neoplasia. Os resultados mostraram uma primária excitaçäo dos monócitos e linfócitos B, seguida de progressiva regressäo porcentual. Há depressäo abrupta inicial dos linfócitos T, os quais após dois dias passam a apresentar lenta recuperaçäo, sem contudo atingir os níveis normais. Os granulócitos apresentam aumento progressivo em seu porcentual do 1§ ao 20§ dia. Os eritrócitos apresentam ligeiro aumento porcentual nos primeiro dois dias e depois progressivamente decaem até o final da experimentaçäo. Os megacariócitos apresentam aumento de porcentagem média inicial (0-2 dias) e no 5§ dia sofrem uma queda abrupta seguida da recuperaçäo gradual até o 20§ dia. As porcentagens nunca ficaram abaixo da normal