Factors associated with serum alanine transaminase activity in healthy subjects: consequences for the definition of normal values, for selection of blood donors, and for patients with chronic hepatitis C. MULTIVIRC Group.

In clinical research, the definition of the upper limit of normal (ULN) alanine transaminase (ALT) is never detailed. However, such a definition can vary and may have practical consequences. Our aim was to assess factors associated with serum ALT activity in apparently healthy subjects and then to apply seven different definitions of ULN in three different populations so as to assess the prevalence of subjects with normal ALT among blood donors and among hepatitis C patients before (normal ALT hepatitis C patients) and after treatment (interferon [IFN] responders). ALT measurements were performed in the same laboratory using the same technique; 1,033 donors were prospectively investigated, 186 patients with hepatitis C never treated and 40 patients treated with 3 MU three times per week of IFN-alpha for at least 6 months. The seven definitions (D) of ULN were: D1: 95th percentile of ALT; D2: 95th percentile after separating males and females; D3: males and females separately, ULN=10 (mean of log10 ALT + 1.96 SD); D4: ULN=45 IU/L given by the manufacturer; D5: mean + 1 SD after exclusion of the 5% extreme values; D6: 95th percentile after separating subjects with body mass index (BMI) under or equal to the median (23); and D7: 95th percentile after separating subjects according to BMI and sex. BMI and male sex were independently associated (P < .0001; logistic regression) with ALT, without an association with alcohol. The range of ULN varied from 26 IU/L in females (D5) to 66 IU/L in males with BMI >23 (D7). Depending on the definition, the prevalence of blood donors with normal ALT varied from 82% to 96%, i.e., a range of 14%; that of hepatitis C patients with normal ALT varied from 16% to 27%, i.e., a range of 11%; the prevalence of IFN responders varied from 25% to 42%, i.e., a range of 17%. Definitions of normal ALT values should be adjusted for sex and BMI to reduce artificial heterogeneity in blood donor selection and in hepatitis C clinical studies.

Suppression of HLA-specific alloantibodies by high-dose intravenous immunoglobulins (IVIg). A potential tool for transplantation of immunized patients.

Renal transplantation in patients presenting end-stage renal failure can be hampered by the presence of alloantibodies against HLA antigens. In 4 out of 5 patients with HLA-specific alloantibodies waiting for a renal allograft, treatment with high-dose i.v. Ig resulted in a prolonged suppression (over 3 months) of most of the panel-reactive anti-HLA antibodies (PRA). Intravenous polyclonal human Ig (IVIg) and F(ab')2 fragments from IVIg inhibited the binding of patients' plasma and IgG fractions to peripheral blood lymphocytes from normal donors as well as their cytotoxicity, suggesting that the in vivo effect of IVIg was mediated by the presence, in the IVIg preparation, of anti-idiotypes directed against idiotypes borne on the anti-HLA antibodies. Thus, treatment with IVIg can be a valuable tool toward the transplantation of immunized patients.

Definition of a new supertypic HLA class II determinant (LAR) associated with HLA-DR2 and -DR7.

A serum from a patient (LAR), immunized by pregnancies and blood transfusions, reacted with cells carrying HLA-DR2 and/or -DR7 specificities (titer 1:200-1:1000). Absorption-elution experiments showed that the allo-serum recognized a determinant shared by DR2 and DR7 cells. The high correlation coefficients (0.90-1) with these specificities suggested that the supertypic specificity LAR was carried by the first DR molecule encoded by DRB1 gene. LAR is another example of new supertypic specificities, reflecting structural homologies between alleles at HLA class II loci.

Expression of ABH and X (Lex) antigens on platelets and lymphocytes.

We used a panel of reagents, polyclonal and monoclonal antibodies, and lectins to define the expression of the ABH- and Lewis-related specificities on platelets and lymphocytes. We also determined the expression of the alpha 2- and alpha 3-L-fucosyltransferases necessary for their biosynthesis. The antigens that could be detected by immunofluorescence and Western blot analysis were based on type 2 monofucosylated structures. Antibodies directed toward types 1, 3, and 4 ABH-, X- and Lewis-related antigenic determinants were always negative because the small amounts of ABH and Lewis antigens adsorbed from the serum could not be detected by these techniques. The presence of the type 2 ABH antigens on intrinsic glycoproteins was controlled by the H gene. This correlates with the presence of alpha 2-L-fucosyltransferase and the absence of alpha 3-L-fucosyltransferase on platelets. In contrast, ABH antigens were not detected by immunofluorescence on normal peripheral lymphocytes. These cells thus have only the small amounts of antigens adsorbed from the serum, these being under control of the secretor and Lewis genes. This correlates with the absence of alpha 2-L-fucosyltransferase on lymphocytes. When lymphocytes were transformed in vitro by the Epstein-Barr virus (EBV), however, they strongly expressed the X and sialylated X antigens, which are specific markers of normal granulocytes and monocytes, respectively. Treatment of EBV-transformed lymphoblastoid cell lines with 12-O-tetradecanoylphorbol-13-O-acetate significantly decreased the expression of X and sialylated X antigens along with that of surface immunoglobulins, whereas it induced a significant expression of the H antigen under control of the H gene.

[Study of the HLA-DQ system by the complement fixation test on lymphocytes stimulated by phytohemagglutinin. Existence of HLA-DQX allele(s)]. / Etude du système HLA-DQ par réaction de fixation du complément sur lymphocytes stimulés par la phyto-hémagglutinine. Existence d'allèle(s) DQX.

The complement fixation microtechnique against PHA blasts has been used to study HLA-DQw1, 2, 3 specificities with sera from multiple transfused patients and/or from multiparous women. Several sera (6 or 7) have been used to define each DQ specificity. The sera have been chosen because of their reactivity with cells from HLA-DR 1, 2 or w6 donors (for DQw1), DR3 or 7 donors (for DQw2,) DR4 or 5 donors (for DQw3). Correlation coefficients between DQ and DR specificities were from 0.56 to 0.91. Correlation coefficients between sera were from 0.51 to 0.92 in each cluster of sera. The segregation of DQw1, 2, 3 specificities has been studied in 46 families with 234 children. This study showed haplotypes lacking DQw1, 2, 3 specificities. The segregation of such 11 DQX haplotypes has been observed in 38 children from 8 families; 5 children were DQX/DQX homozygotes. Up to now, no serological reagent defining the specificity (or specificities) corresponding to DQX has been found. No preferential association was observed between DQX and DR specificities. The gene frequencies observed in 170 haplotypes in these 46 families were as follows: DQw1: 0.400; DQw2: 0.252; DQw3: 0.282; DQX: 0.065. Detecting DQ specificities seems easier by CF on PHA blasts than by lymphocytotoxicity microtechnique against B lymphocytes and monocytes from pheripheral blood. This suggests that PHA blasts express larger quantities of DQ molecules than B lymphocytes and monocytes. The results confirm that complement fixation microtechnique against PHA blasts is efficient for HLA-DQw typing.

Heterogeneity of Lewis antibodies. A comparison of the reaction of human and animal reagents with synthetic oligosaccharides.

Human as well as animal anti-Lewis reagents were shown to have different binding patterns to synthetic structures chemically related to the Lewis epitopes. Two main types of cross-reactions were found: (1) Cross-reactions among type 1 Lewis epitopes (Lea, Leb and Lewis disaccharide). This type of cross-reaction among different type 1 structures was predominant in anti-Lea reagents (16 out of 18), although it was also present in some anti-Leb reagents (4 out of 14). (2) Cross-reactions of Lea and Leb with their type 2 isomers X and Y. The Leb-Y cross-reaction was more frequent (7 out of 14) than the Lea-X cross-reaction (2 out of 18). The serological property of some anti-Lewis reagents reacting with cord cells ('Lex') is also shown to be heterogeneous although probably related to common features of the type 1 Lea and Leb epitopes and independent of the type 2 X and Y epitopes.