In vitro cultured allogeneic cytotoxic t cells mediate hematopoietic GVHD without gut GVHD despite expression of functional LPAM (α4β7 integrin)
Year: 2006
Type: article
Abstract: We and others have shown that in vitro cultured CD8 cytotoxic T cells (CTL) have attenuated GVHD. It has been shown that expression of LPAM on CD8 T cells is important for gut homing specificity in GVHD. Recently, retinoic acid (RA) has been shown to upregulate LPAM expression on naive T cells. We hypothesize that in vitro cultured CTL without RA lack the ability to cause GVHD in part due to deficient LPAM expression. We used an established murine GVHD model in which B6SJL Sp/LN cells were stimulated against DBA splenocytes with IL-2 and IL-7 with and without addition of RA (100 nm). Day 14 comparison of CTL and CTLRA revealed comparable CD4 and CD8 populations. CTL with and without RA showed CD8 LPAM expression of 58% and 0.8% and CD8 CCR9 53% and 10% respectively. In vitro cytotoxicity was comparable between CTL and CTLRA: 41% vs 51% (n = 3, P = .30). Both CTL groups had comparable in vitro migration towards SDF (P = ns) but CTLRA had increased migration towards TECK; 17.3% vs 4.6% (n = 4, P = .01). For in vivo homing, 107 labeled cells from each CTL with (CFSE) and without RA (TRITC) were coinjected intravenously and analysed after 16 hours. CTLRA had increased homing to Peyers patch and MLN compared to CTL without RA [homing index (CTLRA/CTL) 2.3 and 2.5 respectively]. This finding is exaggerated in the radiated host [homing index (CTLRA/CTL) 15 for PP and 11 for MLN]. CTL and CTLRA (5 × 106 cells each) were injected intravenously with or without C57BL/6J BM into irradiated (600 rads) B6D2F1 recipients (6 groups; radiation control, CTL, CTLRA, BM control, CTL + BM, CTLRA + BM). Mice were followed for clinical GVHD scores and CBC and histopathologic GVHD scores (liver, skin, lung, small and large intestines) were obtained. Both CTL groups without BM rescue developed lethal BM aplasia around day 24; however, histopathologic GVHD scores were similar (Table 1). CTL and CTLRA groups with BM rescue had full hematopoietic recovery, yet had similar histopathologic GVHD scores (BM control; 3.9, CTL + BM; 5, CTLRA + BM: 3.9, P = ns). Our data demonstrate that both CTL and CTLRA cause a lethal hematopoietic GVH reaction which could be abrogated by parent BM. Despite high LPAM and CCR9 expression, significant in vitro migration to TECK and in vivo homing to gut associated lymphoid tissues, RA treated CTL did not cause significant GVHD in gut, liver or skin. This suggests that defective gut homing alone may not be sufficient to explain the attenuated GVHD from cultured CTL (Table 1). Tabled 1Parameter (Mean)Radiation ControlCTLCTLRAP Value⁎CTL or CTLRA vs radiation control group.Hb (g/dL)12.23.83.1.0001WBC × 106/L1000300300.07Platelets × 103/L667 20050 20029 500.003Combined GVHD histology score4.94.44.2.30 CTL or CTLRA vs radiation control group. Open table in a new tab
Authors: R. Kalpatthi, K. Nicol, L. Hendey, M. Boyer
Institution: Nationwide Children's Hospital
Language: English
Subfield: Hematology
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $3,650
OpenAlex ID: W1992532015