When each study was excluded from the analyses, higher mean IL-4 levels were found in severe than uncomplicated malaria (P < 0.05), except after excluding the study by Elhussein et al. (P = 0.909) [36] and Singotamu et al. (P = 0.079) [20] from the meta-analysis (Fig. 5). This evidence concerns the gene IL4 and malaria.