The frequency of complete remission and that of relapse within the observation period was similar in A\FAA positive and A\FAA negative AIH\1 patients (table 3?3).). SMA\negative), and in 10 controls (6%), of whom five had hepatitis C, two AIH\2, two PBC and one CD. The association between A\FAA and the SMA\T/G pattern was statistically significant (p 0.0001). A\FAA levels were higher in SMA\T/G positive than SMA\V positive AIH\1 patients and controls (p 0.0001). A\FAA positivity was significantly associated with higher \globulin and IgG levels, but did not correlate with other considered parameters. PRKAA2 Conclusion IKK-IN-1 The modified A\FAA ELISA strictly correlates with the SMA\T/G pattern and is a reliable and operator independent assay for AIH\1. Detection of A\FAA, even if devoid of prognostic relevance, may be useful when interpretative doubts of standard IIF arise. test was used for the comparison of continuous data. Nominal variables were correlated by contingency tables. Significance was set at p 0.05. Statistical analysis was performed using GraphPad InStat (version 3.0a for Macintosh), and StatView (version 5.0.1 for Macintosh; SAS Institute Inc). RESULTS SMA was detected by IIF in 61 of 78 patients (78%) with AIH\1 (47 (60%) had SMA\T/G, 14 (18%) had SMA\V), and in 32 (20%) of the 160 controls (25 with hepatitis C, 2 with AIH\2, 2 with PBC, and 3 with CD; all 32 had the SMA\V pattern). SMA reactivity was of the IgG class in all but two coeliac patients. The mean optical density of the A\FAA ELISA for the 100 blood donors was 0.250, and the resulting OD cutoff was calculated at 0.500, higher than the low positive control reported in the manufacturer’s instructions (0.420). The absorbance of 0.500, corresponding to 30?AU (500/42025?=?30 AU), was therefore chosen as our modified cutoff level. The prevalence of SMA and of A\FAA is summarised in table 1?1. Table 1?Prevalence of A\FAA and SMA in the study population SMA: 70.5% 78%, p?=?0.3; A\FAA SMA\T/G: 70.5% 60%, p?=?0.2. According to our modified cutoff, A\FAA were present in 55 (70.5%) patients with AIH\1 (mean (SD) 90 (35)?AU) (46 with SMA\T/G, 7 with SMA\V, and 2 SMA negative), and in 10 (6%) of the controls (mean (SD) 42 (6)) (7 with SMA\V and 3 SMA negative; namely 5 HCV positive patients, 2 with AIH\2, 2 with PBC, and 1 with CD), as shown in fig 1?1.. The inter\assay coefficient of variation (CV) of IKK-IN-1 the ELISA was 8.7% and the intra\assay CV was 4.2%. Open in a separate window Figure 1?Serological study by IIF (anti\total human Ig as secondary antibodies) and A\FAA ELISA assay. *A second AIH\2 A\FAA positive patient was negative for SMA. Two further HCV patients were A\FAA positive but SMA negative. Fifty blood donors were also tested and were negative for SMA and A\FAA. A\FAA sensitivity was lower than that of SMA, but higher than that of SMA\T/G, however without reaching statistical significance (70.5% 78%, p?=?0.3 and 70,5% 60, p?=?0.2 respectively). Interestingly, 46 (98%) of the 47 SMA\T/G positive patients with AIH\1 also had A\FAA, the correlation between SMA\T/G and A\FAA being statistically significant (p 0.0001, Fisher’s exact test). The level of absorbance (AU) for SMA\T/G positive AIH\1 patients was significantly higher than that for SMA\V positive AIH\1 patients and controls (median 89?AU (range 12 to 178) 20.7 (range 2 to157), respectively; p 0.0001, Mann\Whitney test). However, no correlation was observed between A\FAA optical density readings, AU, and SMA titre. According to the manufacturer’s cutoff (20?AU), A\FAA were detected in 63 of the 78 AIH\1 patients (46 with SMA\T/G, 10 with SMA\V, and 7 SMA negative), but also in 35 controls (namely 15 HCV positive patients, 6 with AIH\2, 6 with PBC, 5 with CD and 3 blood donors). Table 2?2 shows patient by patient results with the two different assays. Table 2?Reactivities of the 78 patients with AIH\1 thead th colspan=”2″ align=”left” valign=”bottom” rowspan=”1″ No.* /th th colspan=”2″ align=”left” valign=”bottom” rowspan=”1″ SMA T/G? /th th colspan=”2″ align=”left” valign=”bottom” rowspan=”1″ SMA V? /th th colspan=”2″ align=”left” valign=”bottom” rowspan=”1″ Titre /th th colspan=”2″ align=”left” valign=”bottom” IKK-IN-1 rowspan=”1″ A\FAA /th th align=”center” valign=”bottom” rowspan=”1″ colspan=”1″ ELISA? /th /thead 53??0?1.7078?+1:40?2.0029??0?2.0071??1:640?4.0052??0?5.0077??0?5.0030??0?7.0070??0?7.6018?+1:5120?7.7550?+80?8.1028??0?9.4051??0?10.0031?+1:40?11.2049+?1:640?12.0017??0?14.0054??0?20.5046?+1:80?20.7027?+1:160?23.0055??0?23.0032??0?23.6047?+1:40?25.0019??0?27.0048??0?28.1072+?1:80+31.0040??0+34.5069+?1:160+35.0016+?1:10240+38.9556+?1:320+45.0041+?1:1280+47.0045?+1:320+50.0061+?1:5120+54.001+?1:320+54.6020+?1:5120+55.6042+?1:320+56.0044??0+57.9557+?1:320+58.0015+?1:40+64.7043+?1:160+65.0059?+1:160+65.0014+?1:160+67.0058+?1:160+67.8073+?1:5120+69.4021+?1:320+71.1574+?1:320+72.8033+?1:320+73.002+?1:160+74.6568?+1:80+80.0013+?1:640+83.3037?+1:5120+85.2060+?1:640+89.0022+?1:640+89.003+?1:320+89.0038+?1:1280+89.9034+?1:2560+90.304?+1:160+92.9562+?1:160+95.009+?1:160+98.0039+?1:160+98.0023?+1:320+101.0063+?1:640+102.0075+?1:640+102.005+?1:320+103.0067+?1:1280+103.008+?1:640+107.0064+?1:5120+123.0012+?1:640+126.0024+?1:640+126.006+?1:320+126.0011+?1:640+130.0035+?1:320+131.0065+?1:640+135.0025+?1:320+137.007+?1:640+141.0066+?1:640+141.0036+?1:1280+144.0076+?1:640+148.0026?+1:1280+157.0010+?1:5120+178.00 Open in a separate window A\FAA AU.