Dean Mann

Association of HLA profiles with early plasma viral load, CD4+ cell count and rate of progression to AIDS following acute HIV-1 infection

Background:Host genetic factors, such as HLA alleles, play an important role in mediating the course of HIV-1 disease progression through largely undefined mechanisms. Objectives:To examine the association of HLA markers with HIV-1 RNA plasma viral load and other factors associated with course of disease progression in HIV-1 infection. Design and methods:A group of 139 HIV-1 seroconverters from the Multicenter AIDS Cohort Study had been typed for a variety of HLA markers. HIV-1 RNA plasma viral load was measured from frozen plasma specimens obtained approximately 9 months following seroconversion. CD4+ cell counts were available from the same study visit. Statistical analysis was performed using survival techniques and linear regression models to quantify the relative associations of an HLA score profile, HIV-1 RNA plasma viral load, CD4+ cell count and age with each other and with rate of progression to AIDS and death. Results:Cox proportional hazards models showed statistically significant differences in time to AIDS by HLA score profile category per unit increase [relative hazard (RH), 0.64; P < 0.0001], HIV-1 RNA plasma viral load per 10-fold increase (RH, 2.04; P = 0.0003), and CD4+ cell count per 100 cell (× 106/l) increase (RH, 0.90; P = 0.02). Multivariate linear regression showed that viral load was 39% lower (P = 0.0001) for each unit increase in HLA score profile and 13% lower (P = 0.002) for each 100 cell (× 106/l) increase in CD4+ cell count. Conclusions:The means by which the HLA score profile influences the time to AIDS is probably through immunologic responses that affect the rate of HIV-1 replication, as manifested by the HIV-1 RNA plasma viral load during the first 6–12 months following acute infection.

Cell Surface Differentiation Antigens of the Malignant T Cell in Sezary Syndrome and Mycosis Fungoides

Using a panel of monoclonal antibodies and rabbit heteroantisera, we have studied the cell surface markers of peripheral blood (PB) Sezary cells from six patients with mycosis fungoides or Sezary syndrome, disease grouped within the spectrum of cutaneous T cell lymphomas (CTCL). Furthermore, we have studied two cell lines (Hut 78 and Hut 102) derived from malignant Sezary T cells from CTCL patients. The monoclonal antibody 3A1 defines a major human PB T cell subset (85% of PB T cells) while the antigen defined by the monoclonal antibody 4F2 is present on a subset (70%) of activated PB T cells and on circulating PB monocytes. In contrast to normal subjects in whom 60-70% of circulating PB mononuclear cells were 3A1(+) T cells, PB mononuclear cells from six CTCL patients studied had an average of only 10.6+/-3.2% 3A1(+) T cells. Whereas 85% of E-rosette positive cells from normal individuals were 3A1(+), virtually all E-rosette positive T cells from the Sezary patients were 3A1(-). Two patients with high numbers of circulating Sezary T cells had both aneuploid and diploid PB T cell populations present; after separation of PB T cells into 3A1(+) and 3A1(-) cell suspensions, all 3A1(-) cells were found to be aneuploid. In contrast to normal resting PB T cells which were 4F2(-), all PB Sezary cells were 4F2(+), suggesting a state of activation. The 3A1 antigen was on a variety of acute lymphoblastic leukemia T cell lines (HSB-2, RPMI-8402, MOLT4, CEM) but was absent on the Hut 78 and Hut 102 Sezary T cell lines. Using rabbit anti-human T and anti-human Ia (p23, 30) antisera, we found that all malignant Sezary PB cells tested were killed by anti-T cell antiserum plus complement but not by anti-Ia plus complement. In contrast, Sezary cell lines Hut 78 and 102, were killed by both anti-T cell antiserum and anti-Ia plus complement. Similar to 3A1(-) normal PB T cells, 3A1(-) Sezary PB T cells proliferated poorly to phytohemagglutinin and concanavalin A. However, 3A1(-) Sezary T cells were able to provide T cell help towards pokeweed mitogen-induced in vitro B cell immunoglobulin synthesis, an immunoregulatory function limited to 3A1(+) T cells in normal subjects.Thus, the 3A1 antigen is present on 85% of normal PB T cells, and on most T-acute lymphoblastic leukemia lines tested; in contrast the 3A1 antigen is not present on the majority of circulating malignant Sezary PB T cells nor on T cell lines derived from malignant Sezary T cells. The lack of expression of the 3A1 antigen may be associated with malignant transformation of T cells in CTCL and may be an important marker for tracing the clonal origin of the malignant Sezary T cell.

Typing of HLA-DQA1 and DQB1 using DNA single-strand conformation polymorphism

The technique of single-strand conformation polymorphism (SSCP), which is capable of distinguishing DNA sequence variability, was adapted to the identification of the HLA-DQA1 and DQB1 alleles. Eight DQA1 alleles and 12 DQB1 alleles were distinguished by amplifying the second exon of the genes in the presence of radioactive deoxynucleotide, denaturing the products with heat, and separating the single strands by electrophoresis in nondenaturing gels. For DQA1, it was possible to distinguish the eight alleles with standard bis-acrylamide or with a Hydrolink gel matrix. Twelve DQB1 alleles were identified by a protocol employing a combination of oligohybridization and SSCP using products amplified by specific DQB1 primers.

Deficient DR antigen expression on human cord blood monocytes: reversal with lymphokines.

Expression of DR antigen on cord blood (neonatal) human monocytes using complement-mediated cytotoxicity with anti-DR alloantisera and fluorescent-activated cell sorting (FACS) utilizing a battery of anti-DR mouse monoclonal antibodies was assessed. Forty preparations of neonatal cord blood monocytes were purified by adherence and elution from plastic petri dishes: lymphocyte contamination was less than 5% as indicated by esterase and peroxidase stains and cell sizing. By cytotoxicity tests 22 +/- 5.5% (SD) of neonatal monocytes expressed DR compared to its expression on 78.6 +/- 3.1% of adult monocytes. By FACS analysis, the frequency of DR expression on neonatal monocytes was 19-33% compared to 71-82% for adult monocytes. Incubation of neonatal monocytes with concanavalin A (Con A) or phytohemagglutinin (PHA)-stimulated human peripheral blood mononuclear cell culture supernatants (lymphokine) or recombinant interferon-alpha (IFN-alpha) increased the expression of DR antigens in a dose- and time-dependent manner. A Con A-supplemented culture supernatant of unstimulated peripheral blood mononuclear cells had no effect on DR expression. Neonatal monocytes that were pretreated with anti-DR and complement in order to remove DR-positive cells were induced to express DR antigen after 2 days in culture with lymphokine. Thus DR-negative neonatal monocytes can be induced to express DR antigen. These results suggest a correctable maturational deficiency of neonatal monocytes. The inducibility of DR antigen expression by lymphokines and recombinant IFN-alpha suggests that they play an important role in the regulation of immune responses.

A method for using serum or plasma as a source of DNA for HLA typing

A simple method for obtaining DNA from serum and plasma is described. Using appropriate primer pairs the polymorphic segments of HLA class II genes were amplified by the polymerase chain reaction (PCR) from this DNA, and typed using allele-specific oligonucleotide hybridization. When compared with DNA obtained from peripheral blood lymphocytes, the efficiency of the PCR was only minimally compromised and could be augmented by increasing the number of amplification cycles and/or by the addition of glycerol to the reaction mixture. This method serves as a reasonable alternative when no other source of DNA is available.

Late-onset 21-hydroxylase deficiency is an allelic variant of congenital adrenal hyperplasia characterized by attenuated clinical expression and different HLA haplotype associations

Three families with late-onset 21-hydroxylase deficiency were studied. Homozygous females presented with symptoms of mild hyperandrogenism such as acne, hirsutism, oligomenorrhea and menometrorrhagia. A homozygous male was asymptomatic and had reached normal adult height. The diagnosis of 21-hydroxylase deficiency was based upon markedly elevated responses of plasma 17-hydroxyprogesterone during a short (30-min) ACTH infusion test. The propositi of two of the families were diagnosed despite long-standing glucocorticoid therapy and adrenal suppression by using a prolonged (48-hour) ACTH infusion. Heterozygotes of late-onset 21-hydroxylase deficiency had mildly elevated 17-hydroxy-progesterone responses to ACTH. Late-onset 21-hydroxylase deficiency was inherited as an autosomal recessive trait with close linkage to the histocompatibility leukocyte antigens. The B14 haplotype was present in all affected members. One affected female had a daughter with classic, salt-losing 21-hydroxylase deficiency. Mixed heterozygosity of this patient for a classic and a late-onset 21-hydroxylase deficiency allele may have caused the classic phenotype in her daughter (homozygote for 2 classic alleles).

Persistently seronegative men from whom HIV-1 has been isolated are genetically and immunologically distinct

Studies in both monkeys and humans have suggested that transient infection with HIV-1 can occur without provoking a measurable humoral immune response. The objective of this study was to look for genetic and immunologic correlates of transient HIV-1 infection in antibody-negative men from whom HIV-1 had been isolated. The distributions of MHC class I, class II, and TAP (transporter protein associated with antigen processing) region genes were compared between 23 persistently seronegative men from whom HIV-1 was isolated at least once (isol+/Ab-) and 137 men who seroconverted. A subset of 13 of the 23 isol+/Ab- men were compared to 27 seronegative men for distribution of CD25+CD4+ and CD25+CD8+ cells in the absence of exogenous immunologic stimulation. The prevalences of the TAP1.4, and a combination of TAP1.4, and TAP2.3 variants were significantly higher in the isol+/Ab- men. The proportion of CD8+ cells that expressed CD25+ antigen was also significantly higher in the isol+/Ab- men than in the seronegative men. We conclude that isol+/Ab- men may be genetically and immunologically distinct from HIV-1 susceptible men. We hypothesize that activated CD8+ cells may have cleared HIV-1 infection in these men through genetically mediated influences of the TAP genes on the presentation of peptides by HLA class I molecules.

The use of DNA heteroduplex patterns to map recombination within the HLA class II region

Differential DNA heteroduplex patterns were used to investigate inheritance of HLA class II region genes in a family where a living related kidney transplant was under consideration. Serologic typing of the family members for HLA class I (HLA-A, B, and C) and class II (HLA-DR and DQ) alleles indicated that the patient (109) and one sibling (126) had inherited the same maternal and paternal HLA alleles. However, a strong reciprocal mixed lymphocyte response implied that these two individuals were not completely HLA identical. Serologic typing for HLA-DQ was confirmed by allele-specific oligonucleotide typing family members for HLA-DQ alpha and beta genes. To assess a possible nonidentical gene(s), DNA was amplified from all family members at the second exon of the DR beta, DQ alpha, DP alpha, and DP beta genes and the products were analyzed by DNA heteroduplex formation. This method showed that individuals 109 and 126 were identical at DR and DQ but differed at DP. This difference was confirmed by allele-specific oligonucleotide hybridization and indicated that 126 had inherited a recombinant maternal chromosome with a cross-over occurring in the region between the DQ beta and DP alpha genes. These data demonstrate the applicability of DNA heteroduplex patterns in establishing identity-nonidentity of alleles in the major histocompatibility complex.

The Immunoglobulin‐Like Structure of Human Histocompatibility Antigens

HL-A antigens are composed of two polypeptide chains. In the case of HL-A antigens solubilized with papain, these have molecular weights of about 34,000 and 12,000, while those solubilized with detergent have molecular weights of 44,000 and 12,000. The 12,000 MW polypeptide is identical to /?2-niicroglobulin. In the membrane the HL-A antigenic molecule appeared to contain two each of the heavy chain and the light chain. The two heavy chains are linked by disulfide bridge(s) which are located in the portion of the molecule removed after papain proteolysis. The two hght chains {^2microglobulin) are associated with the heavy chains by tight noncovalent bonds. There is one intrachain disulfide bridge for each 11-12,000 MW of polypeptide in the heavy chain as well as in ^2-niicroglobulin. Thus all of the data are compatible with an immunoglobulin-like structure for the HL-A antigens, probably one in which only constant region domains are represented.

Cystic fibrosis-related diabetes is associated with HLA DQB1 alleles encoding Asp-57- molecules.

The incidence of insulin-dependent diabetes in individuals with cystic fibrosis is nearly 100 times greater than in the general population. In the latter group, strong associations with specific HLADQ/A1 andDQB1 alleles have been observed. To determine if a similar distribution of alleles occurs in cystic fibrosis patients with diabetes, a cohort of these individuals was typed forDQA1 andDQB1 alleles. HLADQB1*0201 (Asp57−) was more frequent in diabetics compared to controls (40.4 vs 28%), while the frequency of alleles encoding Asp57+ molecules was lower in diabetics relative to both the cystic fibrosisonly controls (P=0.025) and the general population (P=0.008). The presence of at least one protectiveDQA1-DQB1 heterodimer (i.e., Arg52− and Asp57+, respectively) in cis or trans was significantly lower in the diabetics than in either of the control groups. Thus, the HLA alleles known to be associated with insulindependent diabetes mellitus in the general population are also found in diabetics with cystic fibrosis.