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e14039 Background: CD205 is a type I C-type lectin receptor normally expressed on various APC and some leukocyte sub-populations, characterized by a cytoplasmic domain containing protein motifs crucial for endocytosis and internalization. These features make CD205 ideal to be exploited as target of a novel ADC. MEN1309/OBT076 is a humanized IgG1 antibody against CD205, conjugated through a cleavable linker to a potent maytansinoid microtubule disruptor, DM4. Indeed, impressive results were obtained in high and low CD205 expressing xenografts for solid tumours and NHL. In vitro experimental model describing the by-stander effect of MEN1309 was implemented. Methods:A retrospective analysis to evaluate the CD205 expression on archival NHL biopsies was performed in the CRO-National Cancer Institute, Aviano IT. An immunohistochemistry (IHC) was performed on 1 slide per case, using a commercial antibody NCL-L-DEC205 (clone 11A10, Leica Biosystems). All slides were visually evaluated and a validated staining scoring system was applied, ranging from negative score 0 to strong immunostaining score 3+. Percentages (from 0 to 100%) of negative and positive tumor cells (scored as follows: 1-25% = score 1; 26-50% = score 2; 51-75% = score 3; 76-100% = score 4) were reported for each individual slide.Evaluation of correlations between CD205 expression and clinical characteristics is ongoing. Results: 100 cases of Diffuse Large B Cells Lymphomas (DLBCL) and 33 of Follicular Lymphomas (FL) were analysed. 60% of DLBCL cases were positive for CD205 and 39% had more than 25% of positive cells (score ≥2), while the 16% showed 2+/3+ staining intensity. 79% of FL cases were CD205 positive and 66% had more than 25% of positive cells, while the 27% showed 2+/3+ staining intensity. Conclusions: CD205 is heterogeneously expressed in the majority of DLBCL and FL cases. Data on the correlation between CD205 expression and clinical features will be discussed.MEN1309 has shown anti-tumour activity in vitro and in vivo even in low antigen expressing tumours. Hence CD205 expression among NHL, even if heterogeneous, makes, both DLBCL and FL, promising settings in which to explore MEN1309 activity in an upcoming FIH trial.

Aim of the study The estimation of the upper reference limit (URL) for autoantibodies against thyroid peroxidase (TPOAbs) is a controversial issue, because of an uncertainty associated with the criteria used to correctly define the reference population. In addition, the URL of TPOAbs is method-dependent and often arbitrarily established in current laboratory practice. The aim of this study was to determine the reference limits of TPOAbs in a male sample according to the National Academy of Clinical Biochemistry (NACB) guidelines, and to compare them with those obtained in a female group, for five third-generation commercial-automated immunoassay (IMA) platforms. Methods 120 healthy males and 120 healthy females with NACB-required characteristics (younger than 30 years, TSH between 0.5 and 2.0 mIU/L, normal thyroid ultrasound, absence of thyroid disease and absence of other autoimmune diseases) were studied. Sera were analyzed for TPOAbs concentration using five IMA methods applied in automated analyzers: Immulite 2000 XPi (IMM); Maglumi 2000 Plus (MAG); Kryptor Compact Plus (KRY); Phadia 250 (PHA) and Liaison XL (LIA). Results A statistically significant difference (p