S. Merchav et al., Paroxysmal nocturnal hemoglobinuria associated with in vitro inhibition oferythropoiesis by bone marrow T lymphocytes, ISR MED ASS, 2(1), 2000, pp. 22-24
Background: The etiology of bone marrow failure, a prominent feature of par
oxysmal nocturnal hemoglobulinuria, is presently unknown.
Objectives: To evaluate the possible influence of cellular immune mechanism
s in the bone marrow failure of PNH.
Methods: We studied marrow erythroid colony formation in a patient with par
oxysmal nocturnal hemoglobinuria without hypoplastic/aplastic marrow compli
cations.
Results: In vitro assays revealed a pronounced inhibition of primitive eryt
hroid (BFU-E) progenitor cell growth by marrow T lymphocytes. Removal of T
cells prior to culture resulted in a 4.5-fold enhancement of BFU-E numbers.
Reevaluation of in vitro erythropoiesis during steroid administration indi
cated a persistent, albeit less prominent, T cell inhibitory effect.
Conclusion: Our findings provide the first direct evidence for a cellular i
mmune inhibitory phenomenon accompanying PNH.