RT Journal A1 RUTSTEIN DD, REED EA, LANGMUIR AD, ROGERS ES T1 Immediate serum reactions in man: Classification and analysis of reactions to intravenous administration of antipneumococcus horse serum in cases of pneumonia JF Archives of Internal Medicine JO Archives of Internal Medicine YR 1941 FD July 1 VO 68 IS 1 SP 25 OP 56 DO 10.1001/archinte.1941.00200070035003 UL http://dx.doi.org/10.1001/archinte.1941.00200070035003 AB Since Jan. 1, 1937 reports on the use of concentrated antipneumococcus serum have been submitted on a uniform record to the New York State Department of Health by physicians employing serums produced or purchased and distributed by the Division of Laboratories and Research.1 The questions on that form are concerned, so far as possible, with objective data, so that the effect of interpretation by the reporting physician is minimized. Through a follow-up system, complete reports were obtained in practically every case.2Early study of the material so collected brought to light a number of immediate reactions following intravenous serum therapy which were associated with severe circulatory collapse and which did not seem to be related to protein hypersensitivity in the usual sense. It was recognized that this impression was based on reports which had the disadvantage of containing second hand information of varying degrees of accuracy. In order