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Graft-versus-host disease (GVHD) represents one of the major complications of allogeneic hematopoietic stem cell transplantation. Techniques to prevent GVHD have included ex vivo T-cell depletion of the graft or prolonged in vivo immunosuppression. Both reduce the frequency and severity of GVHD but also reduce T-cell-mediated graft-versus-malignancy effect, and increase the risk of infection. A major goal in transplantation is to prevent alloreactivity while preserving activity against tumors and infectious agents. We have used activation of the Notch pathway to try to generate T cells able to specifically regulate alloantigen responses. We used allogeneic Epstein-Barr virus lymphoblastoid B cells (EBV-LCLs) as stimulator cells. Such LCLs are excellent (allo) antigen-presenting cells and can be obtained in large numbers even from donors who have received extensive chemo/radiotherapy. We overexpressed a Notch ligand, Jagged-1, in these cells by adenoviral vector transduction. Stimulation of CD45RA+ naive T cells by Jagged-1 EBV-LCL reduces production of interferon-γ, interleukin-2, and interleukin-5, but up-regulates transforming growth factor-β1 synthesis, consistent with induction of a regulatory T-cell phenotype. Transfer of these T cells to fresh lymphocyte cultures inhibits proliferative and cytotoxic immune responses to the priming alloantigens while sparing responses to third-party stimulator cells. Notch activation in the presence of alloantigen-presenting cells may therefore be a means of inducing specific regulatory T cells while preserving other T-cell functionality. (Blood. 2003;102:3815-3821)

In an attempt to transduce monocyte-derived dendritic cells (DCs) by a retroviral vector coding for a cell surface marker, we were confronted by the observation of high transfer of the surface molecule in the absence of vector proviral DNA in the treated cells. Indeed, DCs acquired the surface marker by a mechanism independent of the vector machinery, requiring cell-to-cell contact and involving transfer of lipids and a variety of intact membrane proteins. Most important, this property of DCs also includes acquisition of foreign human leukocyte antigen (HLA) molecules. Consequently, DCs become immunological hybrids as they display their own and foreign HLA molecules. The newly acquired HLA is fully functional because it allows recognition by allo-specific T lymphocytes and the binding and presentation of antigen peptides.

We retrospectively analyzed red blood cell (RBC) support and alloimmunization rate in 218 consecutive patients-128 from the Pediatric Department and 90 from the adult Hematology Department-undergoing hematopoietic stem cell transplantation (HSCT) between 1994 and 2000. In the pre-HSCT period, the pediatric patients undergoing auto-HSCT required more RBC support. In the post-HSCT period, pediatric patients transplanted with an unrelated donor required more RBC support (median 13.5 U/10 kg bw) than patients receiving HSCT from a related donor (median 6 U/10 kg bw) or from an autologous source (median 4 U/10 kg bw, P=0.0004). In the pre-HSCT period, 159 out of 218 patients (73%) received a total of 1843 RBC units, with an overall median of 9 U/patient over a median of 24 months (range 4-62); 10 patients (6%) developed a total of 12 alloantibodies, with an alloimmunization rate of 5.4/1000 RBC units. In the post-HSCT period, all but three patients were given a total of 2420 RBC units, with an overall median of 6 U/patient over a median of 4 months (range 1-18); all but one of the pre-existing alloantibodies disappeared and three patients (1%) developed new alloantibodies with an alloimmunization rate of 1.2/1000 RBC units. These newly produced alloantibodies (one anti-M and two anti-E) were detected at +58, +90 and +210 days after HSCT. These findings might suggest a different approach to alloantibody screening tests in patients receiving HSCT, with a subsequent reduction of costs and laboratory workload. We retrospectively analyzed red blood cell (RBC) support and alloimmunization rate in 218 consecutive patients - 128 from the Pediatric Department and 90 from the adult Hematology Department - undergoing hematopoietic stem cell transplantation (HSCT) between 1994 and 2000. In the pre-HSCT period, the pediatric patients undergoing auto-HSCT required more RBC support. In the post-HSCT period, pediatric patients transplanted with an unrelated donor required more RBC support (median 13.5 U/10 kg bw) than patients receiving HSCT from a related donor (median 6U/10kg bw) or from an autologous source (median 4U/10 kg bw, P = 0.0004). In the pre-HSCT period, 159 out of 218 patients (73%) received a total of 1843 RBC units, with an overall median of 9 U/patient over a median of 24 months (range 4-62); 10 patients (6%) developed a total of 12 alloantibodies, with an alloimmunization rate of 5.4/1000 RBC units. In the post-HSCT period, all but three patients were given a total of 2420 RBC units, with an overall median of 6 U/patient over a median of 4 months (range 1-18); all but one of the pre-existing alloantibodies disappeared and three patients (1%) developed new alloantibodies with an alloimmunization rate of 1.2/1000 RBC units. These newly produced alloantibodies (one anti-M and two anti-E) were detected at +58, +90 and +210 days after HSCT. These findings might suggest a different approach to alloantibody screening tests in patients receiving HSCT, with a subsequent reduction of costs and laboratory workload.

In order to study disease mechanisms and potential forms of therapy in glomerulonephritis, a model of experimental autoimmune glomerulonephritis (EAG) has been developed in the rat. We have examined the response of Brown-Norway (BN) rats to a single i.m. injection of collagenase-solubilised homologous (Sprague-Dawley, SD) or isologous (BN) glomerular basement membrane (GBM), with and without complete Freund's adjuvant (CFA). There was a dose-dependent circulating anti-GBM antibody response to all preparations of rat GBM. Animals given either antigen alone at a dose of 2 mg/kg developed circulating anti-GBM antibodies, which reached peak values by 6 weeks (63 +/- 5% following SD GBM; 53 +/- 8% following BN GBM), but did not develop glomerular deposits of IgG or nephritis. Animals given 2 mg/kg SD GBM in CFA developed greater concentrations of anti-GBM antibody by 6 weeks (122 +/- 20%) together with linear deposits of IgG on glomerular and tubular basement membranes (TBM), albuminuria (mean 7 mg/24 h), and variable focal segmental necrotising glomerulonephritis with mild interstitial nephritis. The same dose of BN GBM in CFA produced similar concentrations of circulating antibody (144 +/- 26%), with linear deposits of IgG on GBM but rarely TBM, little albuminuria, and variable mild focal glomerulonephritis. Other strains injected with SD GBM in CFA showed a variable circulating anti-GBM antibody response, which was similar to that of BN rats in PVG and DA rats but lower in LEW and WAG rats. Linear deposits of IgG on the GBM were detected in a proportion of PVG and DA rats, but not in LEW or WAG rats.(ABSTRACT TRUNCATED AT 250 WORDS)

The correlation of blood group to grade, stage and tumor markers at diagnosis and to the subsequent clinical course was investigated in a consecutive retrospective series of 230 patients with primary transitional cell carcinoma of the urinary bladder. The follow-up period was 5-9 years. There were no significant differences in grade, stage or DNA ploidy between patients of blood groups A and O. However, the deletion of ABH blood group isoantigen was found more frequently in tumors from patients of blood group O. Concerning progression of superficial bladder tumors, this was found earlier among patients of blood group O, and in a multivariate analysis this emerged as an independent prognostic factor. The crude and corrected mortality was not significantly higher among patients of group O than among those of other blood groups.

The presence or absence of blood group isoantigens in 78 patients with transitional cell carcinoma of the bladder was correlated with tumor stage and grade, and results of chromosomal analysis. For blood group isoantigen detection the indirect immunoperoxidase method with monoclonal antibodies to A, B and H antigen was used. In 51 per cent of the 59 superficial tumors blood group isoantigens were demonstrable, whereas all deeper infiltrating and higher grade tumors were negative. However in superficial tumors the mode of blood group isoantigen expression did not correlate significantly with tumor recurrence and progression. A consistent correlation was demonstrated among chromosomal numbers, tumor grade and clinical course. The chromosomal abnormalities found and mode of blood group isoantigen expression, even in combination, had no prognostic value additional to the grading criteria used. ( J. Urol, 140: 959"963, 1988 )

A method is described by which the effect of intravesical chemotherapy can be monitored. Cytological samples obtained selectively during treatment were used for morphological and flow cytometric studies, and isoantigen (A, B and H) assessment in 2 patients with urothelial cancer. With flow cytometry even small aneuploid populations in the urothelium could be identified. From the histograms the urothelium was seen to contain 2 different cell populations: 1) diploid and 2) aneuploid. The ratio between aneuploid and diploid cells decreased significantly during treatment. Treatment was continued until no evidence of aneuploid cells could be identified in the histograms. Thus, it is demonstrated that intravesical chemotherapy for certain types of bladder cancer can eradicate the aneuploid cell population. A good correlation was found between cytological studies and flow cytometric measurements. Isoantigen assessment was done in the cell suspension used for morphological and flow cytometric studies. Isoantigen assessment also showed loss of antigens after completion of treatment, indicating that the diploid population was not normal biologically. Thus, 3 parameters can be correlated and related also to topography.

The sera of H-normal, H-weak and H-deficient individuals transferred the same amounts of ABH and Lewis antigens to lymphocytes in culture, confirming that the circulating ABH and Lewis antigens detected by lymphocytotoxicity are independent of the H-h system. These antigens were, as expected, under the control of the secretor and Lewis systems in the same way as exocrine secretions. These results suggest that both circulating ABH and Lewis glycosphingolipids and exocrine ABH and Lewis glycoproteins can be synthesized by the same tissues.

Applicability of the mixed cell agglutination reaction (MGAR of Davidsohn) in histological examination was tested in a case of ABO incompatible blood transfusion, who had died of severe head injury two days after an accident. Massively disseminated intravascular aggregation of erythrocytes was identified as immune agglutination by the modified method of MGAR (Ishiyama & Okada) with precise knowledge of topographic isoantigen localization in tissues. The immune specific agglutination mimics intravascular changes such as hyperemia, stagnation and hemorrhage derived from various circulatory disturbances obtained in routine autopsy materials. ACTA PATH. JAP. 27: 729 ˜ 738, 1977.

AB isoantigens are widely distributed in human tissues and loss of AB isoantigen expression has been shown to be an early marker for carcinomatous transformation in some tissues. We therefore applied the Specific Red Cell Adherence Reaction (SRCA) for detection and localization of AB isoantigens in tissue to the study of benign and malignant proliferative lesions of the breast. Twenty-nine lesions in 19 patients were studied. AB isoantigen expression in normal breast tissue was found to be largely confined to the mammary duct system. Loss of AB isoantigen expression was a consistent feature of intraductal carcinoma (3 of 3 cases). Proliferative lesions associated with fibrocystic disease also demonstrated varying degrees of isoantigen loss (simple cystic disease, 3 of 8 cases; intraductal hyperplasia, 6 of 7 cases; sclerosing adenosis, 4 of 4 cases; and intraductal papillomatosis, 7 of 7 cases negative for isoantigen). In contrast to other systems, loss of AB isoantigen expression in the breast appears to be a consistent marker of apparently benign proliferative duct lesions associated with fibrocystic disease, as well as duct carcinoma. The early loss of AB isoantigen expression in these histologically benign lesions supports a possible link between fibrocystic disease and mammary carcinoma. In contrast to other tissues, loss of AB isoantigen expression in proliferative breast lesions is not necessarily evidence of malignancy.

Three hybridomas secreting monoclonal antibodies, HH1, HH2, and HH3, defining different difucosyl A structures (ALeb or ALey), have been established. Antibody HH1 (IgG2a) reacts specifically with the difucosyl A structure irrespective of a type 1 or type 2 chain, while antibody HH2 (IgG3) reacts exclusively with the difucosyl type 2 chain A (ALey) and does not react with the difucosyl type 1 chain or monofucosyl type 2 chain. Antibody HH3 (IgG2a) reacts exclusively with the difucosyl type 1 chain A (ALeb) and does not react with the monofucosyl type 1 chain A or mono- and difucosyl type 2 chain A. These hybridoma antibodies were obtained by immunization of mice with purified glycolipid antigens and were selected by their reactivity with the specific glycolipid structures. These antibodies, together with previously established monoclonal antibody AH-21, specific for monofucosyl type 1 chain A, and monoclonal antibody TH-1, specific for type 3 chain A, are extremely useful to define blood group A variants present in cells and tissues.

SummaryHomogenates of tumorous and adjacent non-tumorous colorectal tissues from 18 patients were tested for the activities of blood group synthetic enzymes, namely α-D-galactosyl transferase for B isoantigen and α-N-acetyl-D-galactosamine transferase of A isoantigen.The galactosyl transferase activity in non-tumorous intestinal tissue was high in patients with blood group B, intermediate in group AB and was absent in group A or O. As compared with adjacent non-tumorous tissue, the Gal transferase activity increased in tumors by 1.6- to 6.9-fold in four of five patients with blood group B or AB, and the α-N-acetyl-D-galactosaminyl transferase activity increased in three- of six-tumor tissues from patients of blood group A or AB.The results suggest that the reported losses of ABH isoantigen in colorectal cancer are not due to deficiencies of Gal or GalNAc transferase activities involved in the synthesis of blood group antigens.

Summary— A and B blood group specific monoclonal antibodies have been used in an indirect immunoperoxidase technique to detect blood group isoantigen (BGI) on normal transitional epithelium and its possible loss on malignant cells. On all 14 specimens of normal tissue and on 31 of 39 (79%) superficial transitional cell carcinomas of the bladder BGI was detected. The incidence of invasive recurrence in the BGI-negative group (50%) was significantly higher than in the BGI-positive group (13%). It is concluded that this method of detecting BGI expression offers several advantages over existing techniques and identifies a group of patients with superficial transitional cell carcinomas of the bladder who are at higher risk of developing an invasive recurrence.

Intensive plasmapheresis of pregnant and non-pregnant women, immunised to the Rh or Kell isoantigen, lowered the concentration of plasma-proteins, including total IgG and individual antibodies. The lowering of antibody concentration was detected by a method using radioactive anti-D gamma-globulin but not by a conventional agglutination technique. In general, the antibody content mirrored the IgG level during plasmapheresis, although in one pregnant woman the serum anti-D antibody content fluctuated despite a consistent fall in IgG. This patient may have been undergoing stimulation by Rh-positive fetal erythrocytes at the time of plasmapheresis. In all, eight pregnant women were treated by plasmapheresis in addition to conventional therapy. Of these, five gave birth to live infants, of which four survived the early postnatal period. Three non-pregnant women also received plasmapheresis.

Earlier tests for the H-Y (male) antigen in mice were limited to male graft rejection by syngeneic females. The experiments described in this report attest to the specificity of a new serological test for this antigen. Anti-H-Y sera and immune ascites fluid with statistically significant cytotoxic indices were produced in C57BL/6Ha females; a cytotoxicity test of sufficient sensitivity to detect and titrate cytotoxic activity, or, conversely, to detect the presence of the male antigen on C57BL/6Ha male lymphoid cells in vitro, was devised.

SummaryIt has been previously assumed that the “male” isoantigen of mice is determined by a gene located on the Y chromosome. This study seems to indicate that newborn female skin, nourished in a male environment, can be induced to express the male antigen. Hence the expression of this antigen seems to be influenced by the Y chromosome only in its “male-determining” role, and the gene responsible for the production of this antigen may be present in both sexes.

An antiserum with allotypic specificity for mouse gamma(2a)-globulins was prepared in a rabbit by injection of 7S gamma(2)-globulin of C(57)BL/6 mice. The antibody reacted with an isoantigen in the 7S gamma(2)-globulins of normal serum of mouse strains belonging to the lg-1(b) allotype class (C(57)BL/6, C(57)BL/10, and SJL strains). No precipitin reaction was observed with serum from 18 other inbred mice strains representing other lg-1 allotype classes.

SUMMARY The R1 antigen of chicken red cells, which is associated with susceptibility to a subgroup B leukosis-sarcoma virus, has been isolated. This antigen is cross-related to structures on the human blood-group MN antigens and, as in the latter, sialic acid is apparently part of its immunodominant grouping. R1 antigen inhibited influenza viruses and to a lesser extent Vicia graminea anti-N reagent. Plant proteases inactivated the antigen.

Mononucleated cells which form rosettes in vitro with Rh(D)-positive erythrocytes have been found among the circulating leucocytes of two pregnant Rh-isoimmunised female patients. The number of rosette-forming cells in these two patients fluctuated with time. No rosette-forming cells were found with Rh(d)-negative erythrocytes. Five Rh-negative males who had previously been immunised against the Rh isoantigen were restimulated with Rh-positive erythrocytes. The number of rosette-forming cells was found to increase from the 6th day onwards. They reached a peak on day 10 and then gradually fell. It is considered that the finding of rosette-forming cells in the peripheral blood of pregnant isoimmunised women may be of value in the detection of transplacental haemorrhage.

A blot-immunobinding test was used to detect anti-sperm antibodies in human sera and to identify the corresponding auto- or iso-antigens on human sperm. A high proportion of sera at a 1:100 dilution from fertile persons, as well as infertile patients, contains antibodies reactive with sperm. This phenomenon might be physiological. At 1:2,000 dilution, a higher binding capacity was detected in the sera from infertile groups, but a few fertile persons were also positive. Antibodies to a single antigenic determinant with Mr of approximately 14,000 were found in a significantly higher proportion among males with unexplained infertility.

Summary— A specific red cell adherence test which can detect the cell surface ABH blood group antigens was performed on formalin-fixed frozen sections of 38 bladder tumours. In 27 tumours decreased glycosyltransferase activity was suggested, but the site and the degree of the blockade did not seem to be identical in every tumour. Blood group A and B tumours could be grouped into 4 types according to the presence of these 3 isoantigens. One group which showed A or B but no H activity (Type I) consisted only of grade 1, superficial tumours. All of the invasive tumours belonged to other types. For blood group 0 turnours no clear-cut correlation could be found between malignancy of the tumour and the presence of H activity. Eight of 22 grade 2 or 3 tumours and 9 of 21 invasive tumours retained the isoantigen, which seemed to invalidate the use of this test as a predictive indicator. Only where blood group A or B patients were concerned, and the presence of H activity was regarded as abnormal as well as the absence of A and B. could all grade 2 or 3 tumours and all invasive tumours be detected by this test.

Since immune memory in Rh(D)-negative isoimmunized subjects remains through life, even in the absence of measurable anti-Rh(D), we investigated the transformation of lymphocytes from such donors by Rh(D) antigen. The time lapse from the last stimulus was up to 13 years. Mononuclear cells from immunized women were stimulated by Rh(D)- positive erythrocyte stroma. Maximum transformation was observed on the sixth day of culture, with a stroma protein concentration of 8 micrograms/mL of culture medium. The stimulation index (SI) in cells from 11 immunized women was 6.8 +/- 3.1 (mean +/- SD), with a range from 3.1 to 15.0. In five different sets of control cultures, the SI ranged from 0.9 +/- 0.2 to 1.3 +/- 0.4. There was no overlap between stimulated and control cultures. No anti-D could be demonstrated in the serum of four of the 11 immunized cases studied. Also, transformation was observed in mononuclear cells from Rh(D)-negative immunized women with Rh(D)-positive erythrocytes. The findings demonstrate that lymphocytes from isoimmunized Rh(D)-negative subjects maintain the immune memory and are transformed in vitro by the Rh(D) isoantigen.

The immunoperoxidase technic was used to investigate the blood isoantigen status in condyloma acuminata, which is regarded as being caused by the human papillomavirus (HPV). Since HPV is associated with epithelial atypias and intra-epithelial neoplasia, and since epithelial malignant transformation is associated with isoantigen loss, the purpose of the study was to determine if koilocytotic atypias are associated with isoantigen loss. Complete isoantigen loss was seen in 33% of cases, partial loss in 47%, and retention in 20%. The significance of this study lies in being able to recognize those lesions that may be associated with malignant transformation (80%) as indicated by isoantigen loss. Isoantigen retention may identify those epithelial atypias that undergo spontaneous regression. Long range follow-up of such patients will help further elucidate the role of HPV in neoplastic transformation of condylomatous lesions. The immunoperoxidase technic can be used in retrospective studies of condylomata of the cervix.

Evidence is presented that fetal red cell membranes differ from membranes of their dams in isoantigenic and lectin reactivities. Evidence for nonsimultaneous development of ‘adult’ antigenic factors is extended. It is proposed that ‘adult’ phenogroups develop from replacement or displacement of factors in ‘fetal’ phenogroups.

Paraffin material of 31 benign and malignant vascular tumors was investigated with respect to their blood group isoantigen (BG) content by the mixed cell agglutination reaction (MCAR). In capillary hemangioma, BG was found in endothelial cells as well as in solid buds. Benign hemangioendothelioma found in endothelial cells as well as in solid buds. Benign hemangioendothelioma found in children differed from that found in adults in that in juvenile cases only endothelial cells expressed BG whereas in adult cases BG isoantigenity was present in endothelial cells as well as in intercapillary cellular elements. In pericytomas only endothelial cells were BG positive, whereas the tumor cells lacked BG. Similar results were obtained with glomus tumors. All but one hemangiosarcoma were BG negative. In one case, however, which probably resembled a "true" malignant hemangioendothelioma (Stout and Lattes, 1967) the tumor cells contained BG in conspicuous amounts.

Eighteen patients with transitional cell bladder carcinoma and increasingly abnormal ploidy were assembled to evaluate the relation over time between ploidy and ABH isoantigen deletion. Fifteen patients with diploid recurrent tumors and 16 with aneuploid tumors over time were used as controls. ABH isoantigen deletion at diagnosis was closely related to cancer death, while isoantigen assessments on recurrences gave less prognostic information. Aneuploidy at diagnosis also indicated an adverse prognosis, as did recurrent bladder carcinoma with deteriorating ploidy. Patients with tumors deleted of isoantigen expression at diagnosis but with normal ploidy had as bad a prognosis as patients with deleted tumors and aneuploidy, indicating that isoantigen deletion may occur earlier than ploidy changes.

The expression of ABH blood group isoantigen was determined with the avidin-biotin-peroxidase complex method in a retrospective consecutive material of 230 patients with transitional cell bladder carcinoma. The follow-up period was 5 to 9 years. The five-year corrected survival for 65 patients whose primary tumours showed predominant expression of ABH antigens ('positive') was 80% and for 146 patients with predominant deletion ('negative') 60% (p less than 0.01). Of 107 patients with superficial tumours there were 60 negative and 47 positive. In an analysis of early progression, the negative tumours were found to progress more frequently than positive ones (p less than 0.03). Twenty-three per cent of the negative tumours finally progressed during the whole follow-up, compared with 15% of the positive ones; this difference was not significant. Almost all progressing tumours became negative when they reached an advanced stage.

Villous adenomas in the urinary bladder are rare neoplasms whose malignant potential is unclear. A case of a morphologically benign non-invasive mucin producing papillary neoplasm of the urinary bladder associated with cystitis glandularis is presented. Absence of A tissue isoantigen from the neoplastic and metaplastic cells and the presence of H tissue isoantigen in both neoplastic and metaplastic cells is observed in a patient whose blood type is A, indicating incomplete maturation of surface coat constituents. The histologically benign appearance of this lesion may belie a malignant potential.

Parenchymal thymus cells from several strains of normal, non-immunized mice responded to histoincompatible thymus cells with increased incorporation of 3H-thymidine in vitro. The response was most pronounced with mixtures of AKR + CBALB/c thymocytes which were mutually stimulatory, as determined by experiments in which one of the cell populations had been rendered unresponsive by irradiation. Reactivity was not restricted to cell combinations bearing major histo-incompatibilities; increases in 3H-thymidine uptake also occurred in cell mixtures with θ isoantigen differences. The culture technique described allows the assessment of the interaction of antigen with native thymocytes in a completely in vitro system.

The antigen inducing antibody formation after the inoculation into the organism can, under suitable conditions, elicit quite the contrary reaction — specific immunological unresponsiveness or immunological tolerance. The critical factor deciding upon which of the reaction pathways will take place is the amount of antigen. Small doses lead to immunity, whereas large doses of appropriate antigen can induce tolerance. The second type of the immunological reaction to the introduction of antigen can be most easily shown in such an experimental model where the immunized animal is immunologically immature and the material used as antigen is not too foreign to the recipient. The third factor enhancing inducibility of tolerance is the use of antigen which is represented by cells capable of further multiplication in the recipient. Such conditions can be fulfilled if the isoantigen is used, i. e. the cells from another individual of the same zoological species, and the embryo or the newborn animal serves as recipient.

Syngeneic mouse bone marrow cells have been studied with regard to their immunological reactivity in a test system involving the measurement of IgM plaque-forming cell (PFC) levels following the immunization of spleen cells in vitro.Normal level of inhibition expressed by bone marrow cells pretreated with anti-Θ serum and complement suggested the thymic-independent nature of bone marrow-mediated suppression. The inhibition was not due to intracellular materials released from the bone marrow cells. Density centrifugation studies resulted in the isolation of a band of cells enriched in suppressive activity. On the basis of cell-adherent separation procedure, greater antibody-inhibiting activity was associated with the non-adherent bone marrow cell population.

Antibodies to various high-frequency antigens were used to test red cells of members of 12 families of Lu(a-b-) propositi carrying the In(Lu) gene. Kna, Kna-like, McCa, and Sla usually are expressed more weakly on cells of the Lu(a-b-) members than on those of their relatives who were not Lu(a-b-). In most families, In(Lu) also suppresses Yka and Csa expression. Some antiserums are more efficient than others of the same specificity in demonstrating the weakened expression. The expression of Ch and Rg antigens on red cells is not affected by In(Lu).

The role of blood group ABO(H) surface isoantigen measurement in bladder cancer is discussed. The basis for this test is examined and an attempt is made to place the current status of this test in proper perspective.

ISOANTIGENS, thought to be important as histocompatibility antigens, have been identified on membranes of human cells by serological techniques1. In order to interpret serological studies of histocompatibility antigens in terms of an understanding of the molecular representation of gene information, the isoantigens must be obtained in a suitable state for detailed chemical analysis. Preparation of soluble isoantigen in relatively low molecular weight form would be an important step in this direction.