Thresholds of CD4 cells for initiating trimethoprim-sulfamethoxazole prophylaxis in west Africa.

Abstract

PIn industrialized countries, guidelines for the prevention of opportunistic infections in patients with HIV infection have long been well defined and periodically updated [1]. In sub-Saharan Africa, where 70% of HIV-infected people are currently living, some of these international guidelines are not applicable, not only because of the limited resources of most African individuals, but also because of differences in the spectrum of HIV-related morbidity. Among these differences, the most striking are the importance of tuberculosis and bacterial diseases as the first and second causes of mortality, respectively, and the low prevalence of Pneumocystis carinii infection [2]. In Africa, the prophylactic interest in cotrimoxazole is mainly because of its activity against Plasmodium spp., Isospora belli and Toxoplasma gondii, and in its antibacterial activity, which may vary locally depending on the resistance rates of major bacterial pathogens such as non-typhi Salmonella and Streptococcus pneumonia[3,4]. Fig. 1 shows the most recent CD4 cell counts in the 133 episodes of invasive bacterial diseases, isosporiasis, toxoplasmosis and malaria, which occurred between 1996 and 1998 in adults enrolled in the ANRS 059 trial in Abidjan, Côte d'Ivoire [3]. In 35 (26%) of these episodes of severe diseases potentially preventable with cotrimoxazole, the most recent CD4 cell counts were higher than 200/mm3 and the most recent CD4 cell percentages higher than 15%, which is the threshold commonly used in industrialized countries for initiating prophylaxis against P. carinii pneumonia [1]. In addition, 93% of these episodes occurred in patients with CD4 cell counts lower than 500/mm3 or with CD4 cell percentages lower than 25%.Fig. 1.: Cases of invasive bacterial diseases, isosporiasis, toxoplasmosis and malaria, in relation to recent CD4 cell counts. Each plot represents one of the 133 cases of invasive bacterial diseases (n = 84), isosporiasis (n = 13), toxoplasmosis (n = 7) or malaria (n = 29), which occurred in HIV-1-infected adults enrolled in the ANRS 059 trial in Côte d'Ivoire from April 1996 to March 1998. No case of P. carinii pneumonia was documented. The axes show the most recent CD4 cell counts (all within 6 months before the episode of disease). None of these patients received antiretroviral drugs during this period.As previously reported, cotrimoxazole was shown in the ANRS 059 trial to decrease the occurrence of severe clinical events in patients included at WHO clinical stages 2 or 3, and, when stratifying by initial CD4 cell count, this protective effect was significant even in patients with CD4 cell counts of more than 200/mm3 at inclusion [3]. In Côte d'Ivoire, a national consensus statement recommended that cotrimoxazole prophylaxis should be used in HIV- infected adults at WHO clinical stages 2, 3, or 4, or with CD4 cell counts under 500/mm3[5]. One of our patients with a CD4 cell count of more than 200/mm3 was recently advised to stop cotrimoxazole, when consulting in a department of infectious diseases during a trip to Europe. We believe that this figure may help our colleagues from industrialized countries to have a better understanding of these recommendations. Xavier Anglaret Siaka Toure Timothée Ouassa François Dabis Thérèse N'Dri-Yoman