Publisher Summary Early studies pointed to the directions for subsequent investigations and there has been continuing identification of other circulating autoantibodies, characterization of their respective cellular antigens, and demonstration of the relationship between autoantibodies and clinical syndromes. The antibodies identified in these studies have been used extensively by investigators in molecular and cell biology as powerful probes for understanding the precursor messenger RNA (mRNA) splicing. Autoantibodies designated SS-A or Ro and SS-B or La were identified in patients with Sjogren's syndrome (SS) and SLE, and have been shown to target intracellular proteins that may be involved with regulation of RNA polymerase III function. Investigators in the field had long perceived that these spontaneously occurring auto-antibodies in human disease would turn out to be useful reagents in cell biology. It was also appreciated that it was necessary to characterize the molecular nature of the auto-antigens so that in addition to the immunochemical properties, their structure and function might be determined. One of the purposes of this chapter is to show that the new molecular biology of cellular antigens and auto-antibodies could now be providing insights into comprehending some features of autoimmunity. In addition, there appears to be a need for the synthesis of the wealth of information that has accumulated and an evaluation of what it might signify.

Antinuclear antibodies: diagnostic markers for autoimmune diseases and probes for cell biology

Essential Role for Nuclear PTEN in Maintaining Chromosomal Integrity

Publisher Summary Autoantibodies to nuclear antigens (ANAs) have assumed an important place in the diagnostic armamentarium of the clinician because of distinct profiles of ANAs in different diseases. Profiles of ANAs have, therefore, been extremely useful in differential diagnosis, where the disease does not have classical or full-blown manifestations.. Immune complexes formed in the circulation or in situ mediate tissue injury by the activation of complement and other inflammatory mediators. Not only do these antibodies precipitate their respective antigens but also other proteins or nuclear RNAs that might be associated with them in special ways. The reasons for these special associations of protein antigens with specific sets of nuclear RNAs is unknown, but the possibility that there might be functional relationships in these complexed particles is not unreasonable. The key question that pervades the minds of many investigators in this field is the reason for the appearance of ANAs in certain individuals. It is highly improbable that the phenomenon is a random immune response to nuclear breakdown products, because the types of ANAs in different diseases are strikingly different. Some known environmental agents are drugs, such as hydralazine and procainamide, that together with lower levels of hepatic acetyltransferase enzyme predispose the host to the development of ANAs. Another agent may be the Epstein–Barr virus that is a ubiquitous environmental agent.

Autoantibodies to nuclear antigens (ANA): their immunobiology and medicine.

We have examined "preimmune" serum samples from a patient who progressively developed the symptoms of scleroderma CREST over a period of several years. During this period, anti-centromere antibodies (recognized by indirect immunofluorescence) appeared in the serum. Concomitant with the appearance of the anti-centromere antibodies, antibody species recognizing three chromosomal antigens in immunoblots of SDS polyacrylamide gels appeared in the patient's serum. These antigens migrate with electrophoretic mobilities corresponding to Mr = 17, 80, and 140 kilodaltons (kd). Affinity-eluted antibody fractions recognizing the antigens have been prepared from sera of three other patients. Indirect immunofluorescence labeling of mitotic cells using these antibody fractions demonstrates that the antigens are centromere components. We designate them CENP (CENtromere Protein) - A (17kd), CENP-B (80kd), and CENP-C (140kd). The three CENP antigens share antigenic determinants. Immunoblotting experiments show that these patients make antibody species recognizing at least three distinct epitopes on CENP-B and two on CENP-C. Sera from different patients contain different mixtures of the antibody species.

Identification of a family of human centromere proteins using autoimmune sera from patients with scleroderma.

The prognosis of patients with cancer is largely determined by the specific histological diagnosis, tumor mass stage, and host performance status. The management of neoplastic disease with the currently available treatment armamentarium may be further advanced if individual patients' risk factors could be better defined. Some of the determinants of tumor response seem to be expressed at the cellular level in terms of degree of tumor cell differentiation, growth kinetics, and hormone receptor expression, which are not readily appreciated by descriptive morphology. Quantitative cytology in the form of flow cytometry has greatly advanced the objective elucidation of tumor cell heterogeneity by using probes that discriminate tumor and normal cells and assess differentiative as well as proliferative tumor cell properties. Abnormal nuclear DNA content is a conclusive marker of malignancy and is found with increasing frequency in leukemia (23% among 793 patients), in lymphoma (53% among 360 patients), and in myeloma (76% among 177 patients), as well as in solid tumors (75% among 3611 patients), for an overall incidence of 67% in 4941 patients. The degree of DNA content abnormality varies according to disease type, with a predominant excess of 10 to 20% in the hematological cancers, whereas ploidy levels in solid-tissue neoplasms span the entire range from almost haploid to hyperoctaploid abnormalities, with near-triploid mean and median DNA content values. The proportion of cells in the S phase of the cell cycle increases with increasing DNA excess in a number of different solid tumors and in acute leukemia. This cytokinetic parameter permits discrimination of low- and high-grade malignant lymphomas. Several reports demonstrate increasing morphological immaturity to be associated with increasing DNA content abnormality and increasing S percentage, all of which adversely affect prognosis. Among phenotypic tumor cell markers, surface membrane antigens have been extensively studied in lymphoid and myeloid neoplasms by the use of hybridoma-generated monoclonal antibodies, which have recently also found in vitro and in vivo therapeutic application. Cellular RNA content is useful for the objective discrimination of acute leukemias and of multiple myeloma. Newer applications of flow cytometry concern studies in the areas of cytoenzymology and cellular pharmacology. Current research is dedicated to the identification of neoplastic marker probes for DNA-diploid disease ( e.g. , nucleolar antigen) and additional phenotypic ( e.g. , hormone receptors) and cytokinetic ( e.g. , cycle traverse rate, growth fraction) parameters.

From a patient management perspective, a role for flow cytometry is emerging as a tool for diagnosis of cancer (abnormal DNA content), specific histopathological diagnosis (RNA for hematological cancers; surface markers for lymphoid and myeloid neoplasms), prognosis (adverse impact of aneuploidy and high S percentage), and treatment (cytokinetically oriented, monoclonal antibodies, drug pharmacology). The pace of past progress justifies the hope that cytometry may soon provide “fingerprinttype” information of an individual patient's tumor which, if proven prognostically relevant, may provide the basis for treatment selection in the future.

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Flow Cytometry in Clinical Cancer Research

Sera from patients with scleroderma contained several autoantibodies to nuclear antigens which were distinguished by different patterns of nuclear immunofluorescence staining. One of these autoantibodies reacted with centromeric regions of chromosomes. In chromosome spreads, the staining appeared as two small spheres at the centromere, resembling kinetochores. The antigenic determinant appeared to be a protein or polypeptide tightly bound to DNA. The autoantibody was reactive with centromeres of cells derived from humans, mice, and Chinese hamsters. The autoantibody was present in high frequency in the calcinosis/Raynaud's phenomenon/esophageal dysmotility/sclerodactyly/telangiectasia variant (CREST) of scleroderma.

https://www.pnas.org/content/pnas/77/3/1627.full.pdf

Autoantibody to centromere (kinetochore) in scleroderma sera.

Antinuclear antibodies wer demonstrated in the sera of 43 of 45 (96%) patients with progressive systemic sclerosis (22 of 24 with diffuse scleroderma and 21 of 21 with the CREST syndrome variant). This high percentage of positive reactions resulted from the use of a tissue culture substrate (Hep-2) to detect antinuclear antibodies by the indirect immunofluorescent method. Patterns of nuclear staining included diffuse fine speckles, large coarse speckles, nucleolar and centromere staining. When organ sections such as mouse kidney were used as substrate for the detection of antinuclear antibodies, nucleolar staining and centromere staining were the two patterns most frequently overlooked. Three types of antibodies appeared to be highly specific for scleroderma: antibody to Sc1-70 antigen, antibody to centromere, and antinucleolar antibody. The anti-centromere antibody appeared to be highly selective for the CREST variant of progressive systemic sclerosis.

Yasuoki Moroi

Papers

Autoantibody to centromere (kinetochore) in scleroderma sera.

Diversity of antinuclear antibodies in progressive systemic sclerosis