Phase I trial of anti-CD3-stimulated CD4+ T cells, infusional interleukin-2, and cyclophosphamide in patients with advanced cancer

PURPOSE

We performed a phase I trial to determine whether in vivo expansion of activated CD4+ T cells was possible in cancer patients. 111Indium labeling was used to observe trafficking patterns of the infused stimulated CD4+ T cells. The influence of cyclophosphamide (CTX) dosing on immunologic outcome was also examined.

PATIENTS AND METHODS

Patients with advanced solid tumors or non-Hodgkin's lymphoma received CTX at 300 or 1,000 mg/m2 intravenously (i.v.). Leukapheresis was performed to harvest peripheral-blood mononuclear cells (PBMCs) either just before the CTX dose, or when the patient was either entering or recovering from the leukocyte nadir induced by CTX. An enriched population of CD4+ T cells was obtained by negative selection. The CD4+ T cells were activated ex vivo with anti-CD3, cultured with interleukin-2 (IL-2) for 4 days, and adoptively transferred. After adoptive transfer, patients received IL-2 (9.0 x 10(6) IU/m2/d) by continuous infusion for 7 days.

RESULTS

The absolute number of CD4+, CD4+/DR+, and CD4+/CD45RO+ T cells increased in a statistically significant fashion in all cohorts after the first course of therapy. The degree of CD4 expansion was much greater than CD8 expansion, which resulted in a CD4:CD8 ratio that increased in 26 of 31 patients. The greatest in vivo CD4 expansion occurred when cells were harvested as patients entered the CTX-induced nadir. One complete response (CR), two partial responses (PRs), and eight minor responses were observed. Trafficking of 111Indium-labeled CD4 cells to subcutaneous melanoma deposits was also documented.

CONCLUSION

CD4+ T cells can be expanded in vivo in cancer patients, which results in increased CD4:CD8 ratios. The timing of pheresis in relation to CTX administration influences the degree of CD4 expansion. Tumor responses with this regimen were observed in a variety of tumors, including melanoma and non-Hodgkin's lymphoma; a high percentage of patients had at least some tumor regression from the regimen that produced the greatest CD4+ T-cell expansion.

Synergistic effects of IL-6 and IFN-gamma on carcinoembryonic antigen (CEA) and HLA expression by human colorectal carcinoma cells: role for endogenous IFN-beta

When administered as single agents, both interferon gamma (IFN-gamma) and interleukin 6 (IL-6) significantly increase carcinoembryonic antigen (CEA) and HLA class I antigen expression on the surface of human colorectal tumour cells. Studies were carried out to determine whether by combining those cytokines a synergistic enhancement of CEA and HLA expression could result. The findings revealed that the administration of 20 units IFN-gamma along with 1.7 ng IL-6, concentrations of each cytokine that individually induced minimal antigenic changes, together synergistically increased CEA and HLA class I as well as induced qualitative changes in HLA expression on WiDr human colon carcinoma cells. The magnitude of the synergistic increases in CEA and HLA class I expression were reminiscent of the level of antigen augmentation observed when administering 20- to 100-fold higher amounts of each cytokine as a single agent. Also, the addition of IL-6 potentiated the IFN-gamma induction of HLA class II expression. The combined administration of IL-6 potentiated the IFN-gamma did not have any additive or synergistic effects on the growth suppression of those tumour cells. Interestingly, utilization of specific neutralizing antibodies for type I interferons abrogated the increases of CEA and HLA expression seen with IL-6 treatment alone or in combination with IFN-gamma. Moreover, reverse transcriptase/polymerase chain reaction analyses revealed a constitutive expression as well as a temporal increase of IFN-beta mRNA transcripts in colon tumour cells treated with IL-6. Therefore, the findings provide indirect evidence that IFN-beta production seems to play a critical role in the ability of IL-6 to upregulate antigen expression alone or in combination with IFN-gamma. These findings provide insight into cytokine combinations that synergistically upregulate tumour-associated and normal HLA antigen expression on the surface of human tumour cells. Those results provide the rationale for the combined use of such cytokines to heighten tumour cell recognition in monoclonal antibody- or cell-mediated-based immunotherapeutic approaches.