Fatty acids in plasma phospholipids were studied in 35 severely malnourished young children with a median age of 29 mo (range: 9-43 mo), who were either seronegative for human immunodeficiency virus-1 (HIV) (n = 16) or suffered from asymptomatic (stage P-1; n = 12) or symptomatic (stage P-2; n = 7) HIV disease. The malnourished children had significantly lower percentages (% by wt) of phospholipid arachidonic (20:4n-6, AA) and docosahexaenoic (22:6n-3, DHA) acids than 25 age-matched healthy control subjects (AA: 7.05% and 8.70% by wt; DHA: 0.92 and 2.61% by wt, P < 0.001). Body weights of malnourished children did not correlate with linoleic (18:2n-6) and alpha-linolenic (18:3n-3) acid values but were significantly and positively correlated with AA and DHA values (r = 0.40, P = 0.02 and r = 0.63, P < 0.0001, respectively). Plasma concentrations (mg/L) of total phospholipid fatty acids did not differ among seronegative, stage P-1, or stage P-2 patients. Percentage contributions of AA and eicosapentaenoic acid (20:5n-3, EPA) did not differ among those seronegative or in stages P-1 and P-2. In contrast, values of dihomo-gamma-linolenic acid (20:3n-6) were significantly (P < 0.05) lower in stage P-2 (2.38 mg/L) than in either seronegative (3.47 mg/L) or stage P-1 (3.66 mg/L) patients. We conclude that the severely malnourished children developed a depletion of both AA and DHA proportional to the degree of malnutrition.(ABSTRACT TRUNCATED AT 250 WORDS)