Graft-versus-host disease after double-unit cord blood transplantation has unique features and an association with engrafting unit-to-recipient HLA match

Manifestations of and risk factors for graft-versus-host disease (GVHD) after double-unit cord blood transplantation (DCBT) are not firmly established. We evaluated 115 DCBT recipients (median age, 37 years) who underwent transplantation for hematologic malignancies with myeloablative or nonmyeloablative conditioning and calcineurin inhibitor/mycophenolate mofetil immunosuppression. Incidence of day 180 grades II to IV and III to IV acute GVHD (aGVHD) were 53% (95% confidence interval, 44 to 62) and 23% (95% confidence interval, 15 to 31), respectively, with a median onset of 40 days (range, 14 to 169). Eighty percent of patients with grades II to IV aGVHD had gut involvement, and 79% and 85% had day 28 treatment responses to systemic corticosteroids or budesonide, respectively. Of 89 engrafted patients cancer-free at day 100, 54% subsequently had active GVHD, with 79% of those affected having persistent or recurrent aGVHD or overlap syndrome. Late GVHD in the form of classic chronic GVHD was uncommon. Notably, grades III to IV aGVHD incidence was lower if the engrafting unit human leukocyte antigen (HLA)-A, -B, -DRB1 allele match was >4/6 to the recipient (hazard ratio, 0.385; P = .031), whereas engrafting unit infused nucleated cell dose and unit-to-unit HLA match were not significant. GVHD after DCBT was common in our study, predominantly affected the gut, and had a high therapy response, and late GVHD frequently had acute features. Our findings support the consideration of HLA- A,-B,-DRB1 allele donor-recipient (but not unit-unit) HLA match in unit selection, a practice change in the field. Moreover, new prophylaxis strategies that target the gastrointestinal tract are needed.

Second-line age-adjusted International Prognostic Index in patients with advanced non-Hodgkin lymphoma after T-cell depleted allogeneic hematopoietic SCT

T-cell depleted allogeneic hematopoietic SCT (TCD-HSCT) have shown durable disease-free survival with a low risk of GVHD in patients with AML. We investigated this approach in 61 patients with primary refractory or relapsed non-Hodgkin lymphoma (NHL), who underwent TCD-HSCT from January 1992 through September 2004. Patients received myeloablative cytoreduction consisting of hyperfractionated total body irradiation, followed by either thiotepa and cyclophosphamide (45 patients) or thiotepa and fludarabine (16 patients). We determined the second-line age-adjusted International Prognostic Index score (sAAIPI) before transplant transplant. Median follow-up of surviving patients is 6 years. The 10-year OS and EFS were 50% and 43%, respectively. The relapse rate at 10 years was 21% in patients with chemosensitive disease and 52% in those with resistant disease at time of HSCT. Nine of the 18 patients who relapsed entered a subsequent CR. OS (P=0.01) correlated with the sAAIPI. The incidence of grades II-IV acute GVHD was 18%. We conclude that allogeneic TCD-HSCT can induce high rates of OS and EFS in advanced NHL with a low incidence of GVHD. Furthermore, the sAAIPI can predict outcomes and may be used to select the most appropriate patients for this type of transplant.

Agonist anti-GITR antibody induces CD8 T cell-mediated tumor rejection

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Background: Signaling through GITR (glucocorticoid-induced tumor necrosis factor receptor) can abrogate the suppressive effects of CD4+foxp3+ regulatory T cells and co-stimulate activated effector CD4+ and CD8+ T cells. We have previously shown that in vivo GITR ligation using the agonist anti-GITR mAb DTA-1 augments concomitant immunity and immunity generated by active immunization with self- tumor antigens. In the present study, we assessed the activity of anti-GITR mAb used alone, focusing on the effects of GITR ligation on CD8+ T cells during tumor growth. Methods: C57BL/6 mice were injected intradermally with B16 melanoma and received 1mg of DTA-1 or control rat IgG intraperitoneally on various days after tumor injection. In some experiments, naïve, CFSE-labeled pmel-1 CD8+ transgenic T cells (specific for the melanoma antigen gp10025–33 epitope) were transferred into naïve recipients 1 day prior to B16 inoculation. Results: DTA-1 treatment on days 0 and 4 led to tumor rejection in 20–30% and 50–60% of mice, respectively, compared with rejection in 0–5% of mice treated with control IgG (p<0.05 for both). Treatment at day 7 or later had no significant impact on tumor-free survival. The importance of CD8+ T cells in mediating DTA-1-induced tumor immunity was demonstrated by 4 findings: 1) in untreated mice, tumor-infiltrating CD8+ lymphocytes significantly upregulated GITR expression during tumor growth; 2) DTA-1-treated mice had greater CD8+ T cell infiltration into tumors than IgG-treated mice; 3) depletion of CD8+ cells completely abrogated the tumor protection provided by DTA-1; and 4) tumor-specific CD8+ cells proliferated more extensively, became more activated, and exhibited greater effector function following DTA-1 administration compared with control IgG. This was most dramatically seen within the tumor (compared with spleen or draining lymph node), suggesting that a major mechanism of tumor immunity induced by anti-GITR mAb may be overcoming impaired CD8+ T cell function within the tumor microenvironment. Conclusions: Ligating GITR using an agonist mAb can by itself augment tumor-specific CD8+ T cell responses and induce rejection of an aggressive, poorly immunogenic tumor. This strategy merits further consideration as an immune-modulating therapy for cancer.

No significant financial relationships to disclose.