Infectious basophilia?
Authors: John P. Kane
Journal: American Journal of Hematology (2015)

To the Editor: In the course of medical practice physicians may glimpse a pattern of disease which suggests a syndrome or a specific origin of a clinical occurrence. I would like to describe here an observation I made as a house officer, of a hematologic disorder, which may have been caused by an infectious agent. I present it now, because with the vastly informative means of detecting infectious agents now in use, the cause may be identified, should a practitioner encounter this disorder again. I was in my internship when routine blood cell counts were done on all the house officers. I was called in to be confronted gravely by a hematologist who said he had to inform me that I had presented with a potentially very important finding: I had a basophilia of eleven percent. Other leukocytes were unaffected. I was informed that this could be due to radiation exposure, which I had not had, but more commonly, the early phase of chronic granulocytic anemia. I had to confront this shocking reality, but decided to continue my clinical training to see what would come of it. In fact, I elected to go skiing that weekend, with the thought that I might not be able to do so for long. At the time, I had a febrile illness, without specific respiratory symptoms, but with considerable lassitude. This wore on for about two weeks during which I gradually began to feel normal again. I had taken to doing my white count and differential after finishing ward work in the evenings, and for a week the high level of basophiles persisted, but then began to diminish. Finally, one night, I heard the hundred cell bell on the manual counter before I counted a single basophile. It was going away! At the same time, my resident was also found to have a basophilia of similar magnitude. He, too had a nondescript febrile illness. By this time the hematologists, knowing that my basophilia had resolved, followed him, finding the same course, resolution over a period of two weeks. Interestingly, a middle aged male patient of ours on the ward developed an identical pattern, showing resolution over the same period of time. This coincidence of three cases of spontaneous basophilia, I think, is highly suggestive of an infectious origin. Should a present day hematologist observe this phenomenon, the application of array analysis and polynucleotide sequencing offers an opportunity, especially in a cluster of cases, to identify a causative agent. This could also reveal a pathway of basophil regulation. Could this be leukemogenic in individuals with the appropriate genomic constitution? It is not unlikely that a cluster of similar cases will be noted again. This time it will afford a unique opportunity for insight into leukocyte biology. The prominent basophilic response to helminthic infection and malaria in mice may involve elements active in the response described here 1. Recent advances in the identification of the role of TSLP 2, 3 in eliciting a specific basophilia suggests that it may play an important role in the response observed in this human cluster. John P. Kane1* 1University of California San Francisco–Medicine/Endocrinology, 555 Mission Bay Blvd, San Francisco, California