Soluble HLA-II expression in African-Americans.

OBJECTIVE: In this study we evaluated the contribution of major histocompatibility complex (MHC) genes to soluble histocompatibility antigen class II (sHLA-II) secretion in African American patients with rheumatoid arthritis (RA). METHODS: A sensitive enzyme-linked immunoassay was used to quantitate sHLA-II in the serum of 7 patients with RA, as well as 28 of their kinships and 49 HLA typed normal African American individuals. RESULTS: Mean sHLA-II values were higher in patients with RA than those in healthy African American individuals (p < 0.05). There were variations in concentrations in individual patients but these were unrelated to any apparent clinical event. The proportion of unaffected family members with detectable levels of sHLA-II was not significantly different than those in normal controls. Neither specific HLA-haplotype, or HLA-allele(s) correlated with high or low sHLA-II secretion. CONCLUSIONS: Our data suggest that sHLA-II molecules are not regulated by MHC linked genes but may be regulated by non-MHC linked genes and racial background may reflect genetic heterogeneity of the expression of this soluble HLA material. These observations contrast with previous observations concerning soluble HLA class I (sHLA-I) molecules in a described population sample which were almost the precise reverse.

Soluble HLA in human body fluids.

There is a growing body of information about the soluble forms of HLA in serum but there are only a few reports discussing sHLA in other body fluids. We quantitated sHLA-I and sHLA-II concentrations in sweat, saliva and tear samples from five normal individuals with known HLA-phenotypes. We also studied sweat samples from an additional 12 normal nonphenotyped subjects, as well as in CSF of 20 subjects with different illnesses, using solid phase enzyme linked immunoassay. Sweat, saliva and tears from normal subjects were found to contain very low or nondetectable amounts of sHLA-I. In contrast, sHLA-II molecules were found in each of these body fluids, although, with considerable variation between individuals. The presence of sHLA-II in saliva was further confirmed by Western-blotting. It was observed that sHLA-II having molecular mass of 43,900 and 18,100 daltons was comparable with that found in serum from normal individuals. In addition, no association of sHLA-II levels with allospecificities in either body fluid or in serum was apparent. The results of CSF sHLA concentrations in different diseases were as follows: (1) High CSF SHLA-I levels were measured during viral encephylitis (n = 3), while none of these patients contained sHLA-II in CSF; (2) The levels of sHLA-II, but not sHLA-I were elevated in CSF of patients during seizure (n = 6) and of patients with neonatal hepatitis (1 of 2) or with connective tissue disease accompanied with viral infection (n = 2); (3) No CSF sHLA-I or sHLA-II could be detected at polyneuropathy (n = 2), or in patients with syphilis (n = 3), or leukemia (n = 2) with evidence of neurologic involvement of central nervous system. Taken together, it may be concluded that the presence of sHLA in several body fluids is physiologically normal. It appears that sHLA-II is the predominant class of HLA molecules present in different body fluids. We propose that the system responsible for sHLA-II production in various body fluids must involve different mechanisms than those responsible for sHLA-I synthesis in serum.

Soluble HLA-I in rheumatic diseases.

OBJECTIVE: To study serum levels of Class I soluble HLA (sHLA-I) in patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), polymyositis or dermatomyositis (PM/DM) or scleroderma and to assess the possible influence of ethnic factors on concentration in each disease group. METHODS: Solid-phase enzyme linked immunoassay was used to measure sHLA-I in the serum of 385 patients with varied ethnic backgrounds (American-Caucasians, African-Americans, Georgian-Caucasians) with rheumatic diseases. Studies on patients were compared to similar measurements of 189 healthy individuals. RESULTS: Mean sHLA-I levels were significantly higher in patients with SLE than those observed in healthy individuals or other rheumatic diseases. Highest concentrations were present in Georgian-Caucasian patients with SLE. American-Caucasian patients with RA or scleroderma had higher sHLA-I levels than normal Caucasian individuals. The majority of patients with PM/DM in all ethnic subgroups were low secretors of sHLA-I. CONCLUSION: Mechanisms underlying the secretion of sHLA-I appear to differ among the rheumatic diseases studied and various ethnic groups. These genetic differences in sHLA-I secretion could be associated with ethnic and pathophysiologic differences among these rheumatic diseases.

Serologic allogeneic chimerism.

BACKGROUND: At least some transplanted livers secrete soluble human leukocyte antigens (sHLA) of donor phenotype into the body fluids of recipients. The individuals in whom this phenomenon occurs are by definition serologic allogeneic chimeras. Because an allogeneic transplanted liver may induce tolerance to itself and other organs in animals of the donor strain, and because maintenance of a soluble antigen in the circulation of any animal in sufficient quantity for a sufficient period generally leads to tolerance, this phenomenon may be biologically important. This study was performed to determine how common this phenomenon is and whether it occurs after transplantation of organs other than the liver. METHODS: We studied 445 serum samples obtained from transplant recipients (liver, n=12; kidney, n=18; and heart, n=8) before and at various intervals after transplantation. All patients studied had allografts that had functioned for more than 1 year. We used an enzyme-linked immunosorbent assay to quantitate sHLA-A2 and sHLA-A1/A3/A11 (as a cross-reacting group). Donor and recipient combinations were selected in which measurable allotypes in donors were not present in recipients. In some instances, an additional allotype was present in a recipient but not in a donor. RESULTS: All liver transplant recipients had detectable donor sHLA in their serum samples after transplantation. In 72% of kidney and 50% of heart transplant recipients, donor sHLA was found persistently in serum samples obtained after transplantation. Interestingly, all heart transplant recipients of HLA-A3, but none of HLA-A2, had detectable donor sHLA in their serum samples, a finding that may be due to technical reasons. High and stable serum concentrations of donor sHLA characterize long-term stable allograft function. CONCLUSIONS: Donor sHLA is produced by all transplanted livers, most transplanted kidneys, and at least half of (but probably more) transplanted hearts. The hypothesis that donor sHLA may be tolerogenic to liver transplants can be expanded to include kidney and heart transplants.

Soluble HLA class I antigens in patients with type I diabetes and their family members.

Our objective was to study a possible contribution of MHC genes to S-HLA-I secretion in patients with Type I diabetes. Quantitatively, we used a highly sensitive enzyme-linked immunoassay to measure S-HLA-I in the serum of a total of 39 patients with Type I diabetes, as well as 36 kinships of 12 diabetic patients and 82 normal individuals with known HLA-phenotypes. S-HLA-I levels were abnormally elevated in patients or their non-diabetic relatives compared to normal controls (p < 0.0009). No complete HLA-haplotype had been identified to be correlated with high or low S-HLA-I secretion. Only the HLA-A23 or A24 (splits of HLA-A9) positive individuals sera were found to contain high S-HLA-I concentrations in all populations studied. The difference in S-HLA-I levels of HLA-A24 patients (n = 4) or their HLA-A24 positive non-diabetic relatives (n = 10) to the group of HLA-A24 normal controls (n = 15) was statistically highly significant (p < 0.0005 and p < 0.0009, respectively). The results suggests that HLA-A24 may confer additional independent risk for the disease expression in male children but not in female siblings. Nevertheless, the data implies that the patients or their non-diabetic relatives carrying the HLA-A24 have increased risk of developing ICA associated with high S-HLA-I levels compared to HLA-A24 negative probands or their kinships with low levels of S-HLA-I. This effect occurred irrespective to other diabetes related HLA-DR alleles. In summary, the results show a pronounced genetic heterogeneity of Type I diabetes with MHC control of the expression of S-HLA-I and possible involvement of hormonal factors that might potentiate a specific synthesis of S-HLA-I. The findings have implications for identifying individuals with a possible risk for developing the disease.

Soluble fraction of class I human histocompatibility leukocyte antigens in the serum of liver transplant recipients.

In previous studies we reported a solid-phase, enzyme-linked immunoassay (ELISA) that can be used to quantitate the soluble fraction of human histocompatibility leukocyte class I antigens (S-HLA-I) and study their relevance in transplantation. In this study we determined the concentration and distribution of S-HLA-I in patients with end-stage liver disease (ESLD), as well as in liver transplant recipients. Sera were obtained from 51 patients with ESLD and 40 donor-recipient pairs. We analyzed the S-HLA-I in sera obtained from liver donors, as well as from liver transplant recipients (patients with ESLD), with sera from the latter obtained before and at various intervals up to 3 yr after transplantation. The results of the analyses justify the following conclusions: 1) Patients with ESLD had mean values of S-HLA-I (909 +/- 596 ng/ml) greater than those for the normal population (643 ng/ml) (P < 0.05); the S-HLA-I secretion decreased with increasing severity of liver disease. 2) Patients with tumors had mean S-HLA-I levels (399 ng/ml) significantly lower than those in patients with ESLD related to other causes. 3) In liver transplant recipients the S-HLA-I levels stabilized at approximately 1 month after transplant and remained relatively stable thereafter (mean level 950 +/- 536 ng/ml). The observed levels were also greater than those for the normal population (P < 0.05). 4) Preoperative and postoperative S-HLA-I values in liver transplant recipients demonstrated a biphasic distribution, dividing patients into high- and low-secretor groups. 5) During the post-transplant observation period, of these selected liver transplant recipients there was no difference between high- and low-secretor groups in the incidence of rejection (high, 70%; low, 67%), graft survival (high, 95%; low, 94%), or patient survival (high, 95%; low, 94%). 6) Measurement of the total amount of S-HLA-I, containing yet undefined ratios of both donor and recipient S-HLA-I, cannot be used to predict a state of tolerance in liver transplant recipients.

Association of serum concentration of soluble class I HLA with HLA allotypes.

We correlated serum concentrations of soluble class I HLA antigens (S-HLA-I) with HLA allotypes in 82 unrelated Caucasian and 58 unrelated African-American putatively normal subjects, as well as in 31 individuals with stable, normally functioning liver transplants. Caucasian and African-American subjects with HLA-A23 or HLA-A24 were high secretors of S-HLA-I. We also observed that some HLA-A allotypes associated with high serum concentrations of S-HLA-I were ethnicity specific. HLA-A33 was associated with high S-HLA-I secretion in African-Americans but not in Caucasians. HLA-A29 was associated with high S-HLA-I secretion in Caucasians but not in African-Americans. All liver transplant recipients studied who were high secretors of S-HLA-I postoperatively carried HLA-A24 or HLA-A29. (There were no HLA-A33 or HLA-A23 allotypes in this group.) The "secretor genes," however, may be autogenous or allogenic (i.e., either donor or recipient HLA-A24 or HLA-A29 resulted in the observed high secretor status in liver transplant recipients after transplantation). It is noteworthy that serum S-HLA-I concentrations were low in all subjects with HLA-A2 regardless of whether the HLA-A2 was of recipient or donor origin. This finding suggests that HLA-A2 could have a suppressive effect on S-HLA-I secretion.

Soluble class I HLA antigens in patients with rheumatoid arthritis and their families.

OBJECTIVE: To study Class I soluble HLA in black patients with rheumatoid arthritis (RA) and their families, and to compare the findings to a group of healthy families of the same racial background. METHODS: ELISA was developed measure soluble HLA Class I (sHLAI) in the serum of 25 patients with RA. Family studies were performed in seven patients with RA and their 28 first degree relatives. These family studies were compared to similar measurements for 66 members of 13 healthy families. RESULTS: Mean sHLAI values were higher in patients with RA than those observed in healthy black individuals. Patients with RA were characterized by elevated serum HLAI, while no change was observed between patients with RA positive or negative for rheumatoid factor. The relatives of patients with RA had high concentrations of sHLAI, compared to families without RA. Highest serum concentrations of sHLAI were found in individuals who were HLA-A23 or HLA-Aw33 positive. CONCLUSION: sHLAI may play a role in the pathophysiology of RA, and there is an association between either augmented release or production of sHLAI and specific HLA allotypes.

Soluble HLA class II concentrations in normal individuals and transplant recipients. Comparison with soluble HLA class I concentrations.

We developed an ELISA to quantify soluble HLA class II (S-HLA-II) in 702 sera obtained from normal subjects, patients with end-stage renal disease, and recipients of renal, hepatic, and cardiac transplants. Concentrations of S-HLA-II were detectable in 124 of 126 normal individuals. The distribution of normal values described a monophasic curve with a skewed distribution. In transplant recipients, there were no differences between preoperative and posttransplant values, but values in liver patients were significantly higher than in kidney patients, and values for heart patients were lowest of all groups. There were periodic variations in concentrations in individual patients, but these were unrelated to rejection, infection, or any other apparent clinical event. S-HLA-II was consistently present in the urine. All of these observations contrast with previous observations concerning soluble HLA class I (S-HLA-I) molecules, which were almost the precise reverse. It seems likely that these clear differences in S-HLA-II and S-HLA-I concentrations relate to different physiologic processes in either production, function, or elimination.

[Anti-nucleic acid antibodies in children with systemic lupus erythematosus and systemic scleroderma and in their relatives living with the probands]. / Antitela k nukleinovym kislotam u detei, bol'nykh sistemnoi krasnoi volchankoi i sistemnoi sklerodermiei, i u ikh rodstvennikov, zhivushchikh sovmestno s probandami.

The nature of antibodies to nucleic acids was studied in children of a Caucasian region suffering from systemic lupus erythematosus (SLE) and systemic sclerodermia (SSD). Two types of antibodies (to two- and one-filament DNA) were revealed in SLE, and in SSD mainly--to one-filament DNA. Antibodies to RNA in patients with SLE were specific for two-filament conformation. Immunogenesis disorders of different degree with respect to DNA and RNA were found; this expressed itself in the synthesis of various classes of immunoglobulins to these antibodies (IgG to DNA and IgM to RNA). High incidence of the RNA-binding activity of relatives living together with probands is noted. These data point to a high occurrence of antibodies to denatured DNA and low incidence of the cases of DNA-binding activity in the blood sera of the patients' fathers and brothers. Thus a combination of three factors: viral, genetic and hormonal in the pathogenesis of this disease is possible.

Antibodies to nucleic acids in systemic lupus erythematosus and rheumatoid arthritis patients and their relatives.

Sera of systemic lupus erythematosus (SLE) patients contain antibodies to double-stranded and single-stranded DNA while antibodies found in rheumatoid arthritis sera are specific mainly to single-stranded DNA. Anti-RNA antibodies in the both cases are directed against double-stranded RNA and belong to the IgM class while anti-DNA antibodies are IgG. Genetic variance analysis based on family correlations suggests that the synthesis of antibodies to DNA is subject to different modes of gene regulations in systemic lupus erythematosus and rheumatoid arthritis patients. In the case of SLE, a high degree of genetic determination is demonstrated, due mainly to the X-chromosomal component of the general phenotypic variance. The failures in the immunoregulation system that are responsible for anti-RNA antibody production are rather similar in the two groups of patients and involve a combination of environmental and autosomal factors.