Lysine and threonine plasma concentrations in Ivorian patients living with human immunodeficiency virus

Côte d'Ivoire is one of the most affected countries in West Africa with HIV/AIDS, with a prevalence of 3.4%. Essential amino acids are needed by the organism as they play key roles in the immune system and they are supplied through diet. The objective of this study was to determine the plasma lysine and threonine status for better medical and nutritional management of patients living with HIV. This study involved 254 individuals: 127 HIV positive and 127 HIV negative (serving as controls) after confirmation of their HIV status through an HIV test (test DETERMINE® and GENIE II). Lysine and threonine were assayed using high performance liquid chromatography (HPLC) on plasma and CD4 lymphocyte count by the method of flow cytometry (FacsCalibur) from whole blood containing EDTA. This study showed that deficiency of lysine was more observed in male HIV infected individuals (66.7%) and threonine deficiency in female HIV infected individuals (17.1%) as compared to the controls subject. The amino acid concentrations as a measure of the degree of immunosuppression was significant for lysine (P = 0.0006) and not significant for threonine (P = 0.8640). The deficiency observed in HIV infected patients taking antiretrovirals is therefore probably due to viral infection and insufficient lysine intake in diet. The threonine concentration depends on the health condition of the subject.


Introduction
Côte d'Ivoire is one of the most affected countries in West Africa with HIV/AIDS, with a prevalence of 3.4%. Essential amino acids are needed by the organism as they play key roles in the immune system and they are supplied through diet. The objective of this study was to determine the plasma lysine and threonine status for better medical and nutritional management of patients living with HIV.

Methods
This study involved 254 individuals: 127 HIV positive and 127 HIV negative (serving as controls) after confirmation of their HIV status through an HIV test (test DETERMINE® and GENIE II). Lysine and threonine were assayed using high performance liquid chromatography (HPLC) on plasma and CD4 lymphocyte count by the method of flow cytometry (FacsCalibur) from whole blood containing EDTA.

Ethical considerations
The study was conducted in accordance with the Helsinki Declaration 2000 on HIV and AIDS research conducted in poor countries and in accordance with the local legislation regarding the national program on treatment management for People Living with HIV/AIDS (Decree No. 411 of December 23, 2001). The blood samples were collected from HIV-positive patients monitored at the Institut Pasteur of Côte d'Ivoire (IPCI), a reference center for public health programs in Côte d'Ivoire supported by the global fund for HIV/AIDS/malaria/tuberculosis. However, for research purposes, written consent was obtained from patients for the use of their blood samples taken during biological monitoring Statistical analysis Statistical analyses were performed using Student's ttest for comparison of averages. The correlation between essential amino acid concentrations and CD4+ T lymphocytes count was determined by the Pearson test. A P < 0.05 value was considered to be statistically significant.

Results 1
This study showed that deficiency of lysine was more observed in male HIV infected individuals (66.7%) and threonine deficiency in female HIV infected individuals (17.1%) as compared to the controls subject. The amino acid concentrations as a measure of the degree of immunosuppression was significant for lysine (P = 0.0006) and not significant for threonine (P = 0.8640). Relating to sex: Regarding deficiency, 66.7% (38/57) male HIV-positive had deficiency of lysine as compared to threonine; 0.0% (0/57 HIV-positive) (Figure 1a). On the other hand, in female PLHIV, 37.2% (26/70) had lysine deficiency as compared to threonine; 17.1% (12/70) of PLHIV (Figure 1b). Regarding excess amino acids, 74.1% (43/57) HIVpositive men had excess threonine and 0.0% (0/57) had excess lysine (Figure 1a). On the other hand, 50.0% (35/70) female HIV-positive have excess threonine and 12.8% have excess lysine (9/70) ( Figure 1b). However, excess threonine was 100% in the male control subjects and 50.0% in women against total absence of excess in lysine in both sexes.

Table 1. Concentrations of L-lysine and Lthreonine in HIV patients and control population according to gender
The difference is significance for P < 0.05 The difference is significance for P < 0.05 Table 2. Distribution of PLHIV and controls based on mean concentrations in L-lysine and Lthreonine Table 3a. Average concentrations of L-lysine and L-threonine in HIV-infected women according to CD4+ count Table 3b. Average concentrations of L-lysine and Lthreonine in HIV-infected men according to CD4+ count * The difference is significance for P < 0.05 Table 4: Correlation between CD4+T lymphocytes cells and plasma amino acids in HIV infected patients.
r Value denotes degree of positive or negative correlation; *P denotes statistically significant value; the difference is significant at P < 0.05

References
The deficiencies observed in HIV positive patients on antiretroviral therapy are therefore due to viral infection and insufficient nutritional intake of lysine. The threonine level depends on the degradation of the health condition of the subject. Therefore, effective early nutritional management of lysine and threonine is very essential to slow down viral replication in order to achieve a better quality of life for patients living with HIV.