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Inter-alpha-trypsin inhibitor (ITI) is a 180-kDa glycoprotein having the role of a serine protease inhibitor. It has been revealed that ITI is not a single polypeptide chain structure, but a complex of three kinds of subunits, two heavy (H1 and H2) chains and a light (L) chain (Bourguignon et al. 1983) with chondroitin sulfate cross-links (Jessen et al. 1988). In situ hybridization showed that the H1, H2 and L chains were encoded by separate genes located on chromosomes 3, 10 and 9, respectively (Diarra-Mehrpour et al. 1989). Genetic variation of ITI on an isoelectric point was reported by Vogt and Cleve (1990) being controlled by mainly three alleles (ITI*1, ITI*2 and ITI*3) with autosomal codominant inheritance. The utility of ITI system has been supported from the results of several population studies (Luckenbach et al. 1991; Vogt et al. 1991a, 1991b; Yuasa et al. 1991; Vogt et al. 1992). However, Vogt et al. (1991b) indicated the cautious application of ITI for paternity testing due to an incomplete expression of ITI phenotypes among infants.

In the previous paper, the present authors reported on diminution in agglutinability of trypsin-treated M and MN red cells with anti-M IgG antibody. This paper deals with the time course of changes in agglutinability and quantitative differences of M agglutinogen of red cells. M agglutinogen of M red cells disappeared much faster than that of MN, and the lowest titer of anti-M IgG antibody to agglutinate M red cells was higher than that to agglutinate MN red cells. The significant difference of agglutination scores was observed in the frequency distribution in 100 cases of M and MN red cells each. Subgroups such as M1 and M2 in M agglutinogen of trypsin-treated red cells reacting with anti-M IgG antibody were unsettled.

The agglutinability of the proteolytic enzyme treated M, N and MN red cells with any one of the anti-M and -N antisera, eluted antibodies and class antibodies was studied. The enzyme-treated 141 and N red cells lost their group specificity in agglutination with the absorbed antisera. However, it was noted that the enzyme-treated M red cells acquired N agglutinogen instead of losing their own M agglutinogen in agglutination with the eluted antibodies. The enzyme-treated N red cells maintained the group specificity. Agglutination of the enzyme-treated red cells with the class antibodies showed clearly that the changes in agglutinability of the red cells were caused by each of the class antibodies.

An 8-year-old girl with myelocytic leukemia was found to have blood group B by detection of B agglutinogen and anti-A agglutinin, agglutinin absorption test, elution test and family studies, but her red cells not agglutinated by anti-B serum amounted to 83% in the peripheral and bone marrow blood, and the red cells failed to react with anti-H. By the microprecipitation method, HbF-cells were found to occupy 79.8% of the whole red cells and 87.9% of the non-agglutinated red cells at the first examination. Thirty-seven days later, fetal hemoglobin containing red cells were 78.1% of the whole red cells, 87.1% of the non-agglutinated red cells, 58.2% of the agglutinated ones and 88.8% of the non-agglutinated red cells treated with bromelin. The quantity of HbF tested by the alkali denaturation method amounted to 54.8% of the non-agglutinated and 28.8% of the agglutinated red cells. HbF components were increased and carbonic anhydrase was reduced to a low level in the patient's blood.

KUMAGAI, R., TOKIWA, K., NAKAYASHIKI, N. and KATSURA, S. Glutamate- Pyruvate Transaminase (GPT) Variant Found in a Disputed Paternity Case. Tohoku J. exp. Med., 1987, 153 (4), 383-388 - GPT variants, GPT2C-1 and GPT2A-2C, were found in samples from a mother and her child, respectively, in a disputed paternity case. The phenotype GPT 2C-1 was determined by polyacrylamide gel electrophoresis performed at alkaline pH and acidic pH; this is probably the first GPT2C-1 detected in Japanese. It was considered that the GPT*2C allele in this family was inherited in a manner of autosomal codominant transmission.

It was reported previously that proteolytic enzyme-treated M red cells lost their reactivity completely with only anti-M IgG antibody. In this paper, M red cells treated with trypsin for 45 min or 3 hr were used to prepare group-specific anti-M IgG and -N IgG antibodies as an adsorbent. It was revealed that M red cells treated for 3 hr could adsorb anti-N antibody in anti-M IgG fraction obtained from crude anti-M serum by DEAE-cellulose column chromatography. The potency of the red cells to adsorb anti-N IgG antibody was similar to that of normal N red cells. Anti-N IgG antibody was prepared by heat-eluting trypsin-treated M red cells sensitized with anti-N fraction. However, the experiments with M red cells treated for 45 min showed unsatisfactory results. It was due to the red cells which could still react with high-titered anti-M IgG antibody but not sufficiently with anti-N IgG antibody.

The presence of M and N antigens in the blood components other than the red cells and various tissues has not been settled yet. The elution method in combination with antiglobulin test reported by the present authors has been used for grouping the stains of the leucocytes, platelets, fibrin, and thymic lymphocytes. All of the test-stains showed obviously positive antigen activities which coincided with blood group of the sources. The experiments of the test-stains treated with trypsin revealed that the treated stains showed a similar agglutin-ability to that of the treated red cells. From the results, it is concluded that the blood components have M or N antigen activity which is a little lower than the red cells.

This paper deals with MN blood grouping of stains of organ homogenate and thin organ sections by means of an elution test in combination with antiglobulin test. Each stain of the liver, spleen, brain, heart, lung, thyroid, kidney and muscle homogenates gave evidently M and N blood group activities in accordance with those of sources. It was considered that non-specific adsorbing potency of the human organ was eliminated in the procedure of homogenate-staining. However, examination on sections showed frequently unsatisfactory results. It was attributed to non-specific adsorption of sections with anti-M and -N antibodies. The present findings may offer a valuable information to identify human tissues in forensic practice.