Y chromosome polymorphisms in native American and Siberian populations: identification of native American Y chromosome haplotypes.

We have initiated a study of ancient male migrations from Siberia to the Americas using Y chromosome polymorphisms. The first polymorphism examined, a C-->T transition at nucleotide position 181 of the DYS199 locus, was previously reported only in Native American populations. To investigate the origin of this DYS199 polymorphism, we screened Y chromosomes from a number of Siberian, Asian, and Native American populations for this and other markers. This survey detected the T allele in all five Native American populations studied at an average frequency of 61%, and in two of nine native Siberian populations, the Siberian Eskimo (21%) and the Chukchi (17%). This finding suggested that the DYS199 T allele may have originated in Beringia and was then spread throughout the New World by the founding populations of the major subgroups of modern Native Americans. We further characterized Native American Y chromosome variation by analyzing two additional Y chromosome polymorphisms, the DYS287 Y Alu polymorphic (YAP) element insertion and a YAP-associated A-->G transition at DYS271, both commonly found in Africans. We found neither African allele associated with the DYS199 T allele in any of the Native American or native Siberian populations. However, we did find DYS287 YAP+ individuals who harbored the DYS199 C allele in one Native American population, the Mixe, and in one Asian group, the Tibetans. A correlation of these Y chromosome alleles in Native Americans with those of the DYS1 locus, as detected by the p49a/p49f (p49a,f) probes on TaqI-digested genomic DNA, revealed a complete association of DYS1 alleles (p49a,f haplotypes) 13, 18, 66, 67 and 69 with the DYS199 T allele, while DYS1 alleles 8 and 63 were associated with both the DYS199 C and T allele.

Strategy for distinguishing a new DQB1 allele (DQB1*0611) from the closely related DQB1*0602 allele via sequence specific PCR or direct DNA sequencing.

A novel DQ6 allele (DQB1*0611) was identified via direct DNA sequencing in an African-American donor for bone marrow transplantation. The allele was not suspected on the basis of a sequence specific PCR assay which instead indicated the presence of DQB1*0602. DQB1*0602 and DQB1*0611 differ in exon 2 only at codon 9 resulting in a tyrosine substitution for phenylalanine. A modification of current DQB1 sequence specific PCR assays was devised which allows distinction between the closely related DQB1*0602 and DQB1*0611 alleles. Preliminary allele frequency studies suggest that DQB1*0611 is rare both in a non-African American sample and in American of African descent carrying DR11, DQ6 haplotypes. The selection of various DQB1*0611 detection methods is discussed.

HLA-B alleles of the Navajo: no evidence for rapid evolution in the Nadene.

New HLA-B locus alleles have been found in South American Amerindian populations but were largely absent in North American Amerindian tribes also descended from this first Paleo-Indian migration. We have now extended these studies to the Navajo, descendants of the second Nadene migration. No new functional alleles were found at the B locus of this tribe. This limited study supports the notion that while new B locus variants are common in South American Amerindians, it is more difficult to find new B locus alleles in North American native peoples. Whether this dichotomy is due to differences in pathogen environment and/or population structures between North and South America remains a subject of speculation.

Polymorphic human specific Alu insertions as markers for human identification.

Alu sequences represent the largest family of short interspersed repetitive elements (SINEs) in humans with 500 000 copies per genome. Recently, one Alu subfamily was found to be human specific (HS). We originally described the use of polymorphis HS Alu insertions as a tool in population studies and recently as tools in DNA fingerprinting and forensic analysis. In this report, we will use this simple polymerase chain reaction (PCR) base technique for the detection of HS Alu insertion polymorphisms. We will test the resolving power of this DNA profiling approach in both population genetics and paternity assessment. At the population level, we will describe the genotypic distribution of five polymorphic Alu insertions among 3 populations from the American continent, one of African origin, the other two Amerindians. Insight into their relationships will be provided. At the family level, we will examine one European American family of seven individuals and the same pedigree will also be characterized by way of the two systems currently and widely used to ascertain paternity: PCR-sequence specific oligonucleotide probe hybridization (PCR-SSO) and PCR-restriction fragment length polymorphism (PCR-RFLP) of human leucocyte antigen (HLA) class II molecules, and a standard RFLP protocol used in forensic casework and paternity studies. The importance and strengths of the methods as well as its perspectives for future use in filiation studies will be evaluated.

HLA-DR53 protects against thrombotic thrombocytopenic purpura/adult hemolytic uremic syndrome.

Class I and Class II HLA antigens were tested in patients treated for thrombotic thrombocytopenic purpura or hemolytic uremic syndrome (TTP/HUS) to determine whether there is a disease association. Based on the results of a pilot trial, retrospective HLA-typing of 18 patients with a diagnosis of TTP/HUS and prospective typing of 12 newly diagnosed patients with TTP/HUS were performed. Twenty-one patients were non-Hispanic Caucasians, 7 were African-Americans, and 2 were Hispanic-Caucasians. Of 30 patients tested, 28 were positive for DR52 (chi-squared = 5.14, P < 0.05), and only two were positive for DR53 compared to 57% of controls (chi-squared = 18.5, P < 0.0005). Diverse DR52 subtypes (DRB3*0101, DRB3*02, and DRB3*0301) were found by oligonucleotide testing in 15 patients, suggesting the association was not with DR52 but with absence of the DR53 antigen. The 2 patients with DR53 were not homozygous. This study suggests that the supertypic antigen, DR53, may govern susceptibility to TTP/HUS, since the relative risk of this disease among DR53 positives is reduced at 0.09 (95% confidence interval, 0.01-0.28). This finding indicates a possible immunogenetic component in the pathogenesis of TTP.

Anti-idiotypic antibodies to anti-DR in patients with rheumatoid arthritis.

Rheumatoid arthritis (RA) sera were evaluated for anti-idiotypic (anti-id) antibodies to HLA-DR antigens (anti-DR) using an ELISA method with murine monoclonal anti-DR antibody-coated microtiter plates incubated serially with either normal or RA sera and peroxidase-conjugated goat anti-human IgG (Fc specific). Specificity was examined using other monoclonal antibodies including anti-Leu 3a, OKM5, OKT8, anti-cytochrome c, and anti-breast tumor antigen. Significant binding of 11/33 (33%) RA to anti-DR was found compared with 0/44 normals (P less than 0.001). Two groups were identified: RA sera reacting with anti-DR and anti-Leu 3a and sera which did not bind to anti-DR but bound to irrelevant monoclonal antibodies. Anti-DR reactivity was differentiated from anti-Leu 3a by competitive inhibition studies. Binding of whole sera and IgG from RA patients to anti-DR was significantly inhibited by DR+ cell extract. The same extract was not inhibitory after selective removal of DR antigen by adsorption on an anti-DR-Sepharose column. These data suggest that anti-id antibodies are directed against the antigen-binding site of id. We conclude that some RA patients have anti-id antibodies potentially involved in immunoregulation of anti-DR antibodies.

Partial characterization of a mitomycin-C resistant T cell.

A cell resistant to concentrations of mitomycin-C associated with the inactivation of many in vitro immune responses is described. This cell is responsive to concanavalin A (Con A), poorly adherent to nylon wool, present in relatively greater numbers in lymph node than other lymphoid tissues, and is relatively radiosensitive. In part, the resistance of this T cell appears to relate to a reduced activity of a microsomal reductase responsible for converting mitomycin-C to its more active form. Discrepancies in reductase activity may represent a way to differentiate among subsets of lymphocytes.

Ethnic differences in the lymphocyte proliferative response induced by a murine IgG1 antibody, Leu-4, to the T3 molecule.

The mitogenic effects of isotypically diverse antibodies to the T3 molecule were examined in genetically diverse population groups. Whereas the OKT3 antibody (IgG2a) was mitogenic for blood mononuclear cells from all individuals tested, the 38.1 antibody (IgM) was consistently nonmitogenic. In contrast, studies of the mitogenic effects of the Leu-4 antibody (IgG1) revealed striking ethnic differences. More than 80% of Caucasians and Negroes were good Leu-4 responders, whereas most individuals of Asian origin, including Indian, Japanese, and Chinese, were either Leu-4 nonresponders or Leu-4 low responders. However, the majority of American Indians, as well as a significant minority of Chinese, were good responders. Cell separation studies confirmed that monocytes govern the different mitogenic effects of the anti-T3 antibodies. The results reveal interesting ethnic differences in monocyte accessory function probably mediated via the Fc-gamma receptor, in the stimulation of T lymphocytes by an IgG1 antibody against the T3 molecule.

A comparison of irradiation and mitomycin as blocking agents in the mixed lymphocyte reaction.

In comparison with administration of mitomycin, lethal irradiation (2,000 rad) of the stimulator cells in a one-way mixed leukocyte culture results in a reduced response due at least in part to the release of inhibitory materials by the irradiated cells. These inhibitory molecules may be partially removed by washing and possess differential reactivity with respect to phytohemagglutinin, concanavalin A, lipopolysaccharide, and pokeweed mitogen.

Studies on the relationship between HLA DR4 and in vitro IgM rheumatoid factor production.

The relationship between the presence of the DR4 antigen and other HLA antigens and in vitro production of IgM-rheumatoid factor by lymphocytes from a group of healthy young subjects was examined. Pokeweed and Epstein--Barr virus-stimulated lymphocyte cultures were examined for the production of rheumatoid factor and immunoglobulins. No significant correlation was found between the presence of the DR4 antigen and in vitro production of IgM rheumatoid factor. The presence of the B18 antigen seemed to identify a population of nonresponders when stimulated with PWM.

Anti-Cra: family study and survival of chromium-labeled incompatible red cells in a Spanish-American patient.

A 22-year-old Spanish-American woman with juvenile rheumatoid arthritis developed anti-Cra after transfusion during colectomy. No Cra negative family members were found among 13 relatives, including four siblings and both parents. Chromium-labeled red cell survival studies showed a T1/2 of 14 days with Cra positive cells. Two units of Cra positive blood were transfused uneventfully for bleeding after ileorectal anastomosis.

Study of HLA alloantigens of the Navajo Indians of North America. II. HLA-A, B, C, DR and other genetic markers.

This report presents the antigen frequencies for HLA-A, B, C, DR, immunoglobulin, and red blood cell systems for the Navajo Indians of North America. HLA-A-B,B-C, and B-DR haplotype frequencies and significant delta values are given. These data are compared with similar data for other American Indians and major non-Indian ethnic groups. Very restricted HLA polymorphism is unique for the Navajo as well as American Indians in general and this feature has important implications with regard to disease association and transplantation.

Effects of irradiation upon the response of murine spleen cells to mitogens.

The mitogenic response of murine spleen cells exposed to graded doses of radiation was evaluated. Low-dose exposures were associated with an augmented response to concanavalin A (Con A) that was most marked with 100 rads. Low-dose augmentation of phytohemagglutinin (PHA) stimulation was equivocal and most pronounced in cells exposed to 10-20 rads. Augmentation was only demonstrable when the cells were irradiated immediately prior to mitogenic stimulation. Timed exposures after stimulation with Con A or PHA showed no evidence that mitogen activation increased radioresistance, although the possibility could not be excluded that activation protects against interphase cell death. Reduced isotope incorporation was associated with all doses of radiation evaluated in cells stimulated with lipopolysaccharide (LPS) or pokeweed mitogen (PWM). On this basis it is concluded that 1) each of the mitogens tested differs in its capacity to stimulate irradiated spleen cells; 2) radiation-induced augmentation is noted with those mitogens (Con A and possibly PHA) known to activate only T cells; 3) radiation-induced augmentation may be due to the release of mitogenically active molecules by injured lymphocytes.

Familial thioamide-induced lupus syndrome in thyrotoxicosis.

We describe 2 relatives both with thyrotoxicosis who developed a lupus-like syndrome after treatment with thioamide derivatives, methimazole (father) and propylthiouracil (son). The lupus syndrome consisted of joint pains, skin rash, and positive antinuclear antibodies (son), all of which resolved after discontinuation of the antithyroid medications. Both patients were identical at the HLA-DR locus suggesting adverse reactions to thioamides may be controlled by immune response genes. The clinician should be cautious about treating other family members when 1 member has had a drug-induced lupus syndrome. This is especially true if the disease in question is a known familial illness such as thyrotoxicosis.

HLA antigen frequencies in cirrhotic and noncirrhotic male alcoholics: a controlled study.

Although epidemiological data suggest that the development of cirrhosis in alcohol abusers is related to the duration and amount of ethanol intake, the fact that only a small percentage of alcohol abusers develop cirrhosis remains unexplained and suggests a possible predisposing genetic factor. Several previous studies have reported an association between various human leucocyte antigens (HLA) and alcoholic cirrhosis. In this study HLA antigen frequencies were determined in Anglo- and Spanish-American cirrhotic and noncirrhotic alcoholics and in a control group of nonalcoholic patients without liver disease. No statistically significant differences in HLA frequencies among the groups were found. Our comparisons of HLA frequencies between cirrhotic and noncirrhotic alcoholic patients do not support the hypothesis that individual susceptibility to the development of alcoholic cirrhosis is genetically determined.

Radiation-induced life shortening in neonatally thymectomized germ-free mice.

Radiation in sufficient amounts is carcinogenic, immunosuppressive, and results in a reduced life span. Similar consequences follow neonatal thymectomy (nTx) in some strains of rodents. The tumorigenic effects of irradiation appear to be partly mediated via suppression of the thumus-dependent portion of the immune response. Our purpose was to determine whether a similar relationship exists for radiation-induced accelerated aging. Female germ-free Charles River mice had neonatal or sham thymectomies within 24 hours of birth. Half of each group was exposed to 700 rads at 6 weeks of age. When mice with histologically malignant tumors were excluded, the combined life-shortening effects of nTx and irradiation were less pronounced than the sum of the individual effects. This suggests that some of the decreased longevity associated with irradiation may be mediated by T-cell injury.

Radiation-induced augmentation of the immune response.

Radiation-induced augmentation of the immune response has been shown to occur both in vivo and in vitro. Evidence is presented to implicate injury to an extremely radiosensitive T cell in the expression of this phenomenon. Experiments are outlined which could be employed to support or reflect this hypothesis.