Blood samples from 49 subjects were submitted to cytotoxic leukocyte tests, which were read double-blind by two laboratory technicians. The results were identical in 78% of the tests and the statistical error of the method was 0.46. In a group of 32 subjects, the cytotoxic test was repeated on 3 consecutive days. Deviations in the results occurred in 18--20% of the tests, the statistical errors varying between 0.38 and 0.43. In a series of serum samples (75 subjects) with positive leukocyte reactions to food antigens, various in vitro procedures were carried out in connection with the cytotoxic test. The following observations were made: In 42 of 58 tests, a positive leukocyte reaction was transferred with the reactive serum to cells from non-reactive subjects. After heating of the reactive serum (56 degrees C, 2 h) and washing of the cells, reactivity was no longer observable in 44 out of 52 tests. Treatment with EDTA consistently blocked expected cytotoxic reactions in 36 tests. DSCG inhibited expected reactions in 45%, antihistamine in 93%, and cortisone in 20% of the tests.

Complement System Proteins↗

PubMedDate not supplied

Antibodies against transglutaminases, peptidylarginine deiminase and citrulline in rheumatoid arthritis--new pathways to epitope spreading.

OBJECTIVE: The findings of the involvement of tissue transglutaminase (tTg) in the pathogenesis of coeliac disease (CD) have stimulated progress in the field of auto-immune diseases. Another calcium-dependent cysteine enzyme, peptidylarginine deiminase type 4 (PAD4), seems to be involved in the pathogenesis of rheumatoid arthritis (RA). There are obvious similarities between Tgs and PADs. METHODS: Using enzyme-linked immuno-sorbent assays, we have measured the occurrence of antibodies against guinea pig (gp) and human recombinant (hr) tTg, PAD and citrulline in 59 controls and 184 RA-patients, of whom 71 were treated with methotrexate (mtx). RESULTS: In addition to the expected antibodies against citrulline (62%), sera from the 113 RA-patients without mtx treatment contained significantly increased frequencies of IgG anti-PAD (35%), IgA anti-gp-tTg (34%), IgA anti-hr tTg (20%), IgG anti-gp-tTg (13%) and IgA anti-hr-FXIII (15%) compared to controls. In sera from the mtx-treated RA-patients the expression of antibodies was reduced. In patients not treated with methotrexate there was a statistically significant correlation between, on one hand, IgG anti-PAD and on the other hand, IgG anti-citrulline, IgA anti-gp-tTg, IgA anti-hr-tTg, IgG anti-gp-tTg, IgG anti-hr-tTg, or IgA anti-hr-FXIII. In the mtx-treated group these correlations were less pronounced. CONCLUSION: In addition to the expected antibodies against citrulline, sera from RA-patients contained antibodies against PAD and against Tgs of at least two kinds, indicating that the specificity for anti-tTg in CD is far from complete. Most of the patients displayed more than one antibody, a possible indication of epitope spreading. MTX-treatment reduced the expression of antibodies.

Adult↗

PubMedDate not supplied

Transamidating enzymes in maternal plasma and placenta in human pregnancies complicated by intrauterine growth retardation.

Transamidases are enzymes, which are necessary for normal clot formation. They fall into two types: thrombin-dependent Factor XIII and thrombin-independent tissue transglutaminases. The investigation showed that human placenta contains not only Factor XIII, but also considerable amounts of a tissue trans-glutaminase identical with an enzyme present in red blood cells. A quantitative assay for transamidases, using incorporation of radioactively labelled putrescine into casein, was applied to placental extracts. With this assay the amounts of thrombin-dependent and thrombin-independent transamidases were determined in the placenta of fullterm infants and term infants who were small for gestational age. The transamidase activities of the placenta in the two groups showed no statistically significant difference. Plasma Factor XIII subunit a antigen concentration was increased by about 40% in midpregnancy and returned to normal nonpregnant values in the 3rd trimester, but when intrauterine growth was retarded the plasma Factor XIII concentration remained elevated. Plasma Factor XIII activities showed a similar variation.

Factor XIII↗