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The relevance of innate immune responses to Plasmodium falciparum infection, in particular the central role of natural killer (NK) cell-derived interferon gamma (IFN-γ), is becoming increasingly recognised. Recently, it has been shown that IFN-γ production in response to P. falciparum antigens is in part regulated by killer-cell immunoglobulin-like receptor (KIR) genes, and a study from malaria-exposed Melanesians suggested an association between KIR genotypes and susceptibility to infection. This prompted us to determine and compare the frequencies of 15 KIR genes in Gambian children presenting with either severe malaria (n = 133) or uncomplicated malaria (n = 188) and in cord-blood population control samples (n = 314) collected from the same area. While no significant differences were observed between severe and uncomplicated cases, proportions of individuals with KIR2DS2+C1 and KIR2DL2+C1 were significantly higher among malaria cases overall than in population control samples. In an exploratory analysis, activating KIR genes KIR2DS2, KIR3DS1 and KIR2DS5 were slightly higher in children in disease subgroups associated with the highest mortality. In addition, our data suggest that homozygosity for KIR genotype A might be associated with different malaria outcomes including protection from infection and higher blood parasitaemia levels in those that do get infected. These findings are consistent with a probable role of KIR genes in determining susceptibility to malaria, and further studies are warranted in different populations.

To determine the outcome of chronic hepatitis in ESRD we studied all 358 renal transplant recipients and 295 hemodialysis patients treated for greater than 1 year since 1970. The incidence of chronic hepatitis (elevated SGOT for greater than 1 year) was 15% (N = 54) in transplanted and 3.4% (N = 10) in dialysis patients. Forty-eight percent (26) of transplanted and 50% (5) of dialysis patients were HBsAg positive. In the transplanted group, the clinical outcome of chronic hepatitis was significantly better in HBsAg-negative compared to HBsAg-positive patients; 11% died, none from liver disease, and 32% remitted after a mean follow-up from start of liver disease of 77.3 +/- 8.2 months, whereas in the HBsAg-positive group 54% (14) died, nine from liver disease, and one remitted after a follow-up of 90.2 +/- 8.9 months. Adverse prognostic factors (age, duration of diabetes, and heart disease) present before ESRD treatment began were similar in both groups, as was duration of follow-up. Only 14% (2/14) of HBsAg-negative patients progressed to chronic active hepatitis on liver biopsy compared to 71% (15/21) of HBsAg-positive patients. Histological stability in those with serial biopsies occurred in 66% (4/6) of HBsAg-negative patients, but in only 18% (13/16) of HBsAg-positive patients with a similar duration of follow-up. No dialysis patients died from liver disease. We conclude that chronic hepatitis occurs more frequently in transplanted than dialyzed patients, and that HBsAg-negative chronic hepatitis has a more benign, clinical, and histological outcome than chronic HBsAg-positive hepatitis in renal transplant recipients.