Tuberculosis (TB) is an infectious disease whose presentation is dependent on host defenses, whereas neuroimmune disregulations are a feature of major depressive disorder (MDD). There are complex interactions between the immune and nervous systems; Tumor Necrosis Factor alpha (TNF-a) has been shown to play a role in the pathophysiology of both TB and MDD. These diseases are prevalent in Mexico, however there is scant research addressing their comorbidity and related immune mechanisms.

Evaluate differences in TNF-a levels and quality of life between subjects with TB and/or MDD.

Thirty-seven subjects (MDD = 10, TB = 9, TB + MDD = 8, controls = 10) were recruited. Instruments used were the SCID-I, Beck Depression Inventory, Hamilton Depression Scale and the World Health Organization Quality of Life survey. A blood sample was obtained from each subject to assess percentage of mononuclear cells positive for TNF-a, using an intracellular cytokines assay.

Highest mean levels of TNF-a were found in the comorbid TB + MDD group (X = 10.46, DE = 14.59) while the control group had the lowest levels (X = 3.26, DE = 4.93). However, when comparing all groups, no statistically significant differences were found. Mean quality of life scores were lower in the MDD (X = 65.6, DE = 5.4) and TB + MDD (X = 66.2, DE = 14.5) groups. When comparing all groups, there were significant differences between TB vs. MDD (p = 0.013), TB vs. TB + MDD (p = 0.004) and MDD vs. control (p = 0.0002) groups.

No significant differences across groups were found regarding TNF-a levels, while subjects with MDD and TB + MDD showed a worse quality of life.