The Authors, studying the condition of immunodepression observed in patients who underwent splenectomy for traumatic lesion, noticed that a significant part of them complained with allergic manifestations. These seemed to appear only in subjects whose Th2 lymphocytes functionality was preserved – as witnessed by normal or increased IL-4 serum level – showing an increased level of IgE too, thus confirming the role of Th2 lymphocytes in stimulating IgE synthesis. On the contrary splenectomized patients with functional harm of the Th2 lymphocytes – proved by low IL-4 serum level – did not show increase of haematic IgE level nor allergic manifestations. The Authors stress that, despite the numerical poorness of the series not allowing definitive judgment, preliminary data are suggestive for an hypothesis – reported below – that needs further confirmation. The ablation of the spleen, organ devoted to remove from the blood antigens – many of these potentially allergizing factors –, allows the prolonged persistence of such sensibilizing agents, thus promoting the onset of allergic manifestations in splenectomized patients whose Th2 lymphocytes function is preserved.