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human-IgM immunoglobulins, the possible effect of R.F. must be checked for, especially pregnant women. We do not know why R.F. is activated during pregnancy but this probably reflects the general adaptation of the immune system in pregnancy. Department of Virology, University ofTurku, 20520 Turku 52, Finland
OLLI MEURMAN PERTTI TERHO AIMO SALMI
ENDOCARDITIS WITH AN ACID-FAST ORGANISM AFTER PORCINE HEART-VALVE REPLACEMENT
SIR,—Atypical mycobacteria are possible contaminants of porcine xenograft heart valves.1-3 With available sterilising techniques, Hancock Laboratories estimate the risk of a contaminated valve escaping detection to be
human-IgM immunoglobulins, the possible effect of R.F. must be checked for, especially pregnant women. We do not know why R.F. is activated during pregnancy but this probably reflects the general adaptation of the immune system in pregnancy. Department of Virology, University ofTurku, 20520 Turku 52, Finland
OLLI MEURMAN PERTTI TERHO AIMO SALMI
ENDOCARDITIS WITH AN ACID-FAST ORGANISM AFTER PORCINE HEART-VALVE REPLACEMENT
SIR,—Atypical mycobacteria are possible contaminants of porcine xenograft heart valves.1-3 With available sterilising techniques, Hancock Laboratories estimate the risk of a contaminated valve escaping detection to be
