Mycobacterium tuberculosis infection and cytogenetic abnormalities among people with HIV

To compare cytogenetic abnormalities among people living with HIV (PLWH) with and without previous exposure to Mycobacterium tuberculosis (Mtb) (both latent tuberculosis infection [LTBI] and active tuberculosis [TB]).

Adult PLWH (≥18 years) were randomly selected at three HIV clinics in Uganda. Previous active TB was confirmed in the clinics' TB records. LTBI was defined as a positive QuantiFERON-TB Gold Plus assay. Participants' buccal mucosal exfoliated cells were examined (per 2000 cells) using the buccal micronucleus assay for chromosomal aberrations (micronuclei and/or nuclear buds), cytokinetic defects (binucleated cells), proliferative potential (normal differentiated cells and basal cell frequency) and/or cell death (condensed chromatin, karyorrhexis, pyknotic and karyolytic cells).

Among 97 PLWH, 42 (43.3%) had exposure to Mtb;16 had previous successfully treated active TB and 26 had LTBI. PLWH with exposure to Mtb had a higher median number of normal differentiated cells (1806.5 [1757.0 - 1842.0] vs. 1784.0 [1732.0 - 1843.0], p = 0.031) and fewer karyorrhectic cells (12.0 [9.0 - 29.0] vs. 18.0 [11.0 - 30.0], p = 0.048) than those without. PLWH with LTBI had fewer karyorrhectic cells than those without (11.5 [8.0 - 29.0] vs. 18.0 [11 - 30], p = 0.006).

We hypothesized that previous exposure to Mtb is associated with cytogenetic damage among PLWH. We found that exposure to Mtb is associated with more normal differentiated cells and less frequent karyorrhexis (a feature of apoptosis). It is unclear whether this increases the propensity for tumorigenesis.