The thiopurine S-methyltransferase (TPMT) genetic polymorphism has a significant clinical impact on the toxicity of thiopurine drugs. It has been proposed that the identification of patients who are at high risk for developing toxicity on the basis of genotyping could be used to individualize drug treatment. In the present study, phenotype-genotype correlation of 1214 healthy blood donors was investigated to determine the accuracy of genotyping for correct prediction of different TPMT phenotypes. In addition, the influence of gender, age, nicotine and caffeine intake was examined. TPMT red blood cell activity was measured in all samples and genotype was determined for the TPMT alleles *2 and *3. Discordant cases between phenotype and genotype were systematically sequenced. A clearly defined trimodal frequency distribution of TPMT activity was found with 0.6% deficient, 9.9% intermediate and 89.5% normal to high methylators. The frequencies of the mutant alleles were 4.4% (*3A), 0.4% (*3C) and 0.2% (*2). All seven TPMT deficient subjects were homozygous or compound heterozygous carriers for these alleles. In 17 individuals with intermediate TPMT activity discordant to TPMT genotype, four novel variants were identified leading to amino acid changes (K119T, Q42E, R163H, G71R). Taking these new variants into consideration, the overall concordance rate between TPMT genetics and phenotypes was 98.4%. Specificity, sensitivity and the positive and negative predictive power of the genotyping test were estimated to be higher than 90%. Thus, the results of this study provide a solid basis to predict TPMT phenotype in a Northern European Caucasian population by molecular diagnostics.

Our observations are consistent with the hypothesis that dissociation or destruction of complement C1 eliminates the prozone effect. Addition of EDTA to serum of highly immunized patients is the easiest way to avoid false-negative results in SAB testing caused by a prozone effect.

Vitiligo is a skin and hair disorder characterized by circumscribed depigmented lesions due to lack of melanocytes in the respective areas. It has been suggested that vitiligo is caused by an autoimmune-mediated destruction of melanocytes. Recently, the presence of a high frequency of skin-homing melanocyte-specific cytotoxic T lymphocytes in the peripheral blood of patients with vitiligo was reported. Our study examines the frequency of melanocyte-specific cytotoxic T lymphocytes in vitiligo patients and its relationship to disease activity. Thirty-two patients with moderate to active vitiligo and 17 control subjects were included. Melanocyte specific reactive CD8(+) T cells were identified by enzyme-linked immunospot assay after stimulation with five peptides from gp100, four peptides from MelanA/MART1, and two peptides from tyrosinase. In selected patients, intracellular interferon-gamma staining for the detection of specific reactive CD8(+) T cells was additionally performed. In seven of 10 patients (70%) with actively progressive disease CD8(+) T cells directed against melanocyte epitopes were detected, whereas only in four of 22 patients (18%) with moderate disease activity such specific reactivity was found. MelanA/MART1 peptides were immunodominant in nine patients reacting against EAAGIGILTV and three patients reacting against ILTVILGVL. Intracellular interferon-gamma staining confirmed the findings obtained by the enzyme-linked immunospot technique. The present study supports the hypothesis that vitiligo is a cytotoxic T lymphocyte-mediated autoimmune disease. The presence of melanocyte-specific reactive CD8(+) T cells seems to be closely related to disease activity.

Adoptive transfer of cytomegalovirus (CMV)-specific T cells can restore longlasting, virus-specific immunity and clear CMV viremia in recipients of allogeneic stem cell transplants if CD4 ؉ and CD8 ؉ CMV-specific T cells are detected in the recipient after transfer. Current protocols for generating virus-specific T cells use live virus, require leukapheresis of the donor, and are time consuming. To circumvent these limitations, a clinicalscale protocol was developed to generate CMV-specific T cells by using autologous cellular and serum components derived from a single 500-mL blood draw. CMVspecific T cells were stimulated simultaneously with CMV-specific major histocompatibility complex class I (MHC I)-restricted peptides and CMV antigen. Activated T cells were isolated with the interferon-␥ (IFN-␥) secretion assay and expanded for 10 days. In 8 randomly selected, CMV-seropositive donors, 1.34 ؋ 10 8 combined CD4 ؉ and CD8 ؉ CMV-specific T cells, on average, were generated, as determined by antigentriggered IFN-␥ production. CMV-infected fibroblasts were efficiently lysed by the generated T cells, and CMV-specific CD4 ؉ and CD8 ؉ T cells expanded if they were stimulated with natural processed antigen. On the other hand, CD4 ؉ and CD8 ؉ T cell-mediated alloreactivity of generated CMV-specific T-cell lines was reduced compared with that of the starting population. In conclusion, the culture system developed allowed the rapid generation of allodepleted, highly enriched, combined CD4 ؉ and CD8 ؉ CMV-specific T cells under conditions mimicking good manufacturing practice.