Background: Human immunodeficiency virus (HIV) infection is associated with a profound dysregulation of the immune system and alterations in the cytokine profile. Tuberculosis, a common opportunistic infection in HIV positive patients, leads to further immune suppression and a faster progression of the disease. This study was conducted to assess and compare the cytokine profiles in HIV positive subjects with and without pulmonary tuberculosis.
Methods: Twenty HIV positive patients and 20 controls were evaluated after being divided into four groups of 10 each--group 1--HIV positive patients without tuberculosis, group 2--HIV positive patients with pulmonary tuberculosis, group 3--healthy adults and group 4--HIV negative patients with pulmonary tuberculosis. After clinical evaluation, the CD4 cell counts and the cytokine profiles--interleukins (IL)-2, 4, 6, 10, 12, interferon gamma (IFN gamma) and tumour necrosis factor alpha (TNF alpha) were studied in all the subjects at the start and after three months of antituberculosis therapy.
Results: the CD4 cell counts were significantly lower in groups 1 and 2 compared to groups 3 (p < 0.01) and the counts in group 2 were significantly lower than in group 1 in both at baseline (p = 0.0076) and at three months (p = 0.089). The levels of the type 1 cytokines (IL-2, IL-12 and IFN gamma were significantly lower in patients in groups 1 and 2 compared to group 3 (p < 0.001 for both). The levels in group 2 were lower than in group 1 (p < 0.001). The type 2 cytokines (IL-4, IL-6, IL-10 and TNF alpha) were higher in group 1 and 2 compared to group 3, though statistically significant for IL-6 in group 1 (p < 0.05) and for IL-4, IL-6 and TNF alpha in group 2. A highly significant (p < 0.0001) positive correlation between CD4 cell counts and type 1 cytokines and a highly significant (p < 0.0001) negative correlation between CD4 cell counts and type 2 cytokines was observed.
Conclusions: A decline in the type 1 and a rise in type 2 cytokines was observed in HIV infection. Patients in group 2 had the lowest CD4 cell counts, lowest levels of type 1 cytokines and highest levels of type 2 cytokines denoting maximum immunosuppression.