Response to the communication of M Hosp et al. on low-cost progression markers in HIV-1 seropositive Zambians.

Abstract

Dear Sir With HIV seroprevalence rates of up to 36% in the adult population, health care facilities in sub-Saharan Africa are being overwhelmed by HIV-positive individuals. In most settings, sophisticated laboratory markers of HIV disease progression are unavailable. To allow a balanced distribution of scarce health care resources, low-cost prognostic indicators are required. Hosp et al. have used the immunoalkaline phosphatase method to determine CD4 counts in HIV-positive individuals in Zambia[1]. A good correlation with fluorescence-activated cell sorter (FACS)-obtained CD4 counts was documented, and the value of FACS CD4 counts correlated with degree of immune suppression, judged by clinical events. Total lymphocyte counts (TLC) were noted to be lower if patients had oral candidiasis, became ill or died during follow-up, but a TLC < 2000 cells/μL had poor predictive value for a CD4 count below 200 cells/μL[1]. The authors did not advocate the use of TLC for prognostic purposes. In a large cohort of South African HIV-positive patients, we previously evaluated the role of the TLC to predict HIV disease progression[2]. A TLC of 1250 cells/μL correlated with a CD4 count of 200 cells/μL, and a TLC < 750 cells/μL was equivalent to a CD4 count below 50 cells/μL. Total lymphocyte and CD4 counts, when added to the World Health Organization (WHO) clinical stage, were equal predictors of progression from WHO stages 1–3 to AIDS, and from AIDS to death. We suggested that a TLC < 1250 cells/μL could be used as a laboratory criterion to commence co-trimoxazole prophylaxis[2]. Others have confirmed the good correlation between CD4 counts and TLC[3]. Tuberculosis (TB) is the commonest opportunistic infection in our region, and a major health care burden in sub-Saharan Africa. When available, chest radiographic pattern can both predict CD4 count and survival in HIV-infected patients[4, 5]. Typical upper-lobe cavitatory disease is associated with a preserved CD4 count and excellent outcome, whereas patients with atypical patterns had low CD4 counts and 50% mortality at 1 year. Lymphopenic patients with TB had a significantly higher mortality than those with a normal TLC[5]. Patients with HIV-related tuberculosis were shown to benefit from co-trimoxazole prophylaxis in a West African study[6]. In our opinion, the combination of WHO clinical stage, performance status and total lymphocyte count allows prognostication of patients with HIV infection, such that individuals at risk of opportunistic infections can be identified and considered for prophylaxis, and that limited resources available may be targeted at patients that are likely to benefit most.