The T-cell pool is anergized in patients with multiple sclerosis in remission.

Relapsing-remitting multiple sclerosis (RRMS) is a complex autoimmune disease of the central nervous system with oscillating phases of relapse and remission. RRMS has been considered to be driven by T helper type 1 (Th1) lymphocytes but new data indicate the involvement of Th17 responses. In the present study, blood samples from patients (n=48) and healthy individuals (n=44) were evaluated for their immunological status. T cells from patients with RRMS expressed high levels of the activation marker CD28 (P<0.05) and secreted both interferon-gamma (CD8: P<0.05) and interleukin-17 upon polyclonal mitogen or myelin oligodendrocyte glycoprotein antigen stimulation. However, T cells from patients with RRMS in remission, in contrast to relapse, had poor proliferative capacity (P<0.05) suggesting that they are controlled and kept in anergy. This anergy could be broken with CD28 stimulation that restored the T-cell replication. Furthermore, the patients with RRMS had normal levels of CD4(+) Foxp3(+) T regulatory cells but the frequency of Foxp3(+) cells lacking CD127 (interleukin-7 receptor) was lower in patients with MS (mean 12%) compared to healthy controls (mean 29%). Still, regulatory cells (CD25(+) sorted cells) from patients with RRMS displayed no difference in suppressive capacity. In conclusion, patients in relapse/remission demonstrate in vitro T-cell responses that are both Th1 and Th17 that, while in remission, appear to be controlled by tolerogenic mechanisms yet to be investigated.

AdCD40L gene therapy counteracts T regulatory cells and cures aggressive tumors in an orthotopic bladder cancer model.

PURPOSE: The aim of this study was to develop an immunostimulating gene therapy for the treatment of orthotopic bladder carcinoma by transferring the gene for CD40L into the tumor site. CD40L stimulation of dendritic cells induces interleukin-12 expression that drives Th1 type of immune responses with activation of cytotoxic T cells. EXPERIMENTAL DESIGN: The gene for murine CD40L was transferred into bladders of tumor-bearing mice using an adenoviral vector construct. To facilitate viral uptake, the bladders were pretreated with Clorpactin. Survival of mice as well as transgene expression and immunologic effect, such as resistance to tumor challenge and presence of T regulatory cells, were monitored. RESULTS: On viral vector instillation, CD40L expression could be detected by reverse transcription-PCR. As a sign of transgene function, interleukin-12 (IL-12) expression was significantly increased. AdCD40L gene therapy cured 60% of mice with preestablished tumors. The cured mice were completely resistant to subcutaneous challenge with MB49 tumor cells, whereas the growth of a syngeneic irrelevant tumor was unaltered. Furthermore, the mRNA expression level of the T regulatory cell transcription factor Foxp3 was evaluated both in tumor biopsies and lymph nodes. There were no differences within the tumors of the different treatment groups. However, Foxp3 mRNA levels were down-regulated in the lymph nodes of AdCD40L-treated mice. Correspondingly, T cells from AdCD40L-treated mice were not able to inhibit proliferation of naive T cells as opposed to T cells from control-treated, tumor-bearing mice. CONCLUSIONS: AdCD40L gene therapy evokes Th1 cytokine responses and counteracts T regulatory cell development and/or function.