Abstract
We investigated, in individuals with HIV-associated sensory neuropathy (HIV-SN), whether having pain at the ankle skin biopsy site was associated with lower intra-epidermal nerve fiber density (IENFD) compared to not having pain at the ankle biopsy site. We recruited 15 individuals with symptomatic HIV-SN. Nine participants had pain at the site where the ankle biopsy was taken, while six participants had no pain at all (n = 2) or had pain that was localised to the feet only (n = 4). Skin punch biopsies were taken from the ankle and the thigh. Biopsies were processed and IENFD quantified using standard protocols. Contrasts between the two groups were made using the overlap of confidence interval (CI) method. We found that IENFD was substantially lower in the group that had pain at the site of the ankle biopsy compared to the other group [6.6 (CI: 5.3 to 7.2) vs. 3.3 (CI: 10.0 to 15.0) fibers/mm]. However, there was no group differences at the thigh biopsy site [15.6 (CI: 15.0 to 15.9) vs 16.2 (CI: 14.5 to 17.8) fibers/mm]. When taking the ratio of ankle IENFD:thigh IENFD, the point estimate for the pain at the ankle group [0.43 (CI: 0.36 to 0.48)] was about half that of the other group [0.81 (CI: 0.68 to 0.87)]. Thus, co-localization of pain to the ankle is associated with meaningful decreases in ankle IENFD.
