DIFFICULTIES OF INTERPRETING PPD REACTIONS OF WOMEN LIVING IN MADANG,PAPUA-NEW-GUINEA

Malaria surveys in Madang, Papua New Guinea, previously distinguished 2 populations of women with significantly different spleen rates and i mmune responses to malaria. Differences between the high (HS) and low (LS) spleen rate groups suggested a defect in cellular immunity in the HS group. This paper reports a survey of purified protein derivative (PPD) responses in a sample of HS and LS women. Eighty-eight of 162 wo men were PPD positive (reaction size >5 mm). There was a marked differ ence in the range and size of PPD reaction between the HS and LS group s. Mean size in the LS group was 20.7 mm and in the HS group it was 12 .1 mm (P=0.02). Failure to show differences in other indicators of spe cific malaria immunity indicated that the difference in PPD response w as not the result of malaria-specific cell-mediated immune suppression . Many women were PPD non-responders in spite of evidence of multiple bacillus Calmette-Guerin (BCG) vaccination scars. There was no differe nce between HS and LS groups in the level of non-response to PPD. The results confirm an early tuberculosis survey indicating that New Guine ans rapidly lose PPD reactivity to BCG vaccination. Ability to maintai n a PPD response, and the quality of response, may vary according to s ex and genetic background.