The effect of FIV infection on CD4+ and CD8+ counts in periradicular lesions

The purpose of this study was to elucidate whether a decrease/increase in T-cell populations is present in the development of periradicular disease in the immunocompromised feline model.

Eight cats were immunosuppressed with steroids prior to infection with feline immunodeficiency virus (FIV). Another eight cats, age and sex matched littermates, were monitored and tested at equivalent periods of time and served as uninoculated, seronegative controls. Periradicular lesions were induced using local bacterial inoculations into the pulp of the canine teeth and assessed after one- and four-week periods, corresponding to the acute and chronic stages of the periradicular disease. Block sections were obtained and specimens were prepared for H & E and immunohistochemical staining for CD4+ and CD8+ receptors. Cells were quantified using a computer imaging system and data analysed using generalized estimating equation (GEE) regression models.

Significantly lower CD4+ counts and CD4+/ CD8+ ratios were observed at all time periods in the periradicular region of the FIV group (P = 0.0006). No significant difference in CD8+ counts was observed between the two groups. In both groups there was a significant difference in the CD4+ counts between one week and baseline, and 1 week and 4 weeks. There was no significant difference between baseline and 4 weeks for either group.

FIV infection reflected decreased CD4+ counts at the periradicular level, however, inflammation and progression of the lesion, appeared to be comparable to the non-immunocompromised controls.