CD4+ and CD8+ T cell subset distribution in the blood of small-bowel-grafted rats: Modification during graft-versus-host disease

We studied the modifications of blood T cell distribution following small-bowel allografting in rats under different experimental conditions. Group 1: ACI (RT1^a) rats were used as small-bowel donors for ACI x Wistar (RT1^y) F₁ hybrid rats (WAF₁) in which graft-versus-host disease (GVHD) developed. Group 2: WAF₁ rats were used as small-bowel donors to ACI rats which developed rejection. Group 3: WAF₁ rats received small bowel from ACI rats hyperimmunized for 10 days (by grafting them with WAF₁ skin) and GVHD developed. Group 4: Wistar rats received small bowel from ACI rats hyperimmunized for 10 days (by Wistar skin) and bidirectional GVHD and rejection were assured. A second set of the same groups which were continuously administered with cyclosporine (15 mg/kg per day s. c. for 15 consecutive days) was also studied. Recipient peripheral blood lymphocytes, obtained at 7 and 15 days following small-bowel transplantation, were stained with monoclonal antibodies anti-rat CD4 and CD8 and then analyzed in an automated flow cytometer. A significant major reduction of CD4⁺/CD8⁺ T cell ratios was shown in rats that developed simultaneous GVHD and rejection with respect to ungrafted rats.