Circulating cytotoxic immune components in dominant Charcot-Marie-Tooth syndrome.

Activated T cells, measured repeatedly in the demyelinating peripheral neuropathy, Charcot-Marie-Tooth syndrome (CMT; hereditary motor sensory neuropathy), might participate in myelin loss by a destructive inflammatory autoimmune process. To explore this possibility, plasma proportions of hydroxyleukotrienes, their fatty acid precursor, arachidonic acid, and lymphocyte epitopes associated with immune cell activation expression were measured in 18 adults with dominant, Type I CMT. Compared to age-matched normal controls, CMT I patients showed eicosanoid-linked immunoactivation by an elevated content of 12-hydroxy-eicosatetraenoic acid (12-HETE) in parallel with a decreased plasma percentage of its fatty acid precursor, arachidonic acid. CMT patients also had increased numbers of peripheral lymphocytes expressing activation-related epitopes, CD25+, CD26+, CD4+, and CD4/CD45RO+ primed memory cells, with enhanced CD8+ cytotoxic cells and soluble CD8 protein content. Therefore, endogenously stimulated CMT I lymphocytes include functional cytotoxic cells which appear to deplete the plasma fatty acid precursor of prostenoid agents during the secretion of potentially destructive cytokines.

Persistently altered T cell immunity in high school students with the congenital rubella syndrome and profound hearing loss.

Because there are frequent progressive and autoimmune complications in children born with the congenital rubella syndrome, we evaluated immunoregulation in eight profoundly deaf adolescents with congenital rubella syndrome who lived in a state school. Serum antiviral antibodies, expressions of peripheral lymphocyte epitopes and serum soluble interleukin 2 receptor (IL-2R) content were compared with those of 16 classmates with profound hearing loss of unknown cause and of 24 age-matched, hearing students from this area. Both deaf groups showed activated but impaired T lymphocyte function compared with normals. Rubella virus alteration of T cell function was suggested in congenital rubella syndrome students by elevated numbers of both CD4+ helper and CD25+ IL-2R cells with unusually low released soluble IL-2R content. In contrast in deaf classmates elevated CD25+ and CD16+ natural killer cell groups and soluble IL-2R content with low numbers of CD4+ helper cells and CD4+ populations were of unknown etiology. Defective immunoregulation of the congenitally deaf to pathogens inherent in their environment may lead to autoimmune and other complications.

Phagocytosis of latex beads is defective in cultured human retinal pigment epithelial cells with persistent rubella virus infection.

Phagocytosis, a secondary function of retinal pigment epithelial (RPE) cells essential to sight, was significantly decreased, when measured with latex beads, during persistent rubella virus (RV) infection of human cultured RPE cells. A target for RV in vivo, RPE cells infected with RV (RPE/RV) ingested fewer fluorescent microspheres (26%) than did uninfected RPE cells (68%) (P < 0.001), as measured by flow cytometry. In RPE/RV cells, with characteristic RPE monolayer appearance and normal growth during subculturing over 6 months, persistent RV infection was shown by specific RV antigen immunofluorescence, by the presence of the RV genome in RPE/RV cell messenger RNA, and by recovery of cell-free RV after cocultivation with Vero cells. The adhesion of latex beads to apical cell surfaces of RPE/RV and uninfected RPE cells appeared similar, as imaged by scanning electron microscopy. Cytoskeletal actin, a component of phagocytosis in RPE, appeared altered in 60 to 75% of RPE/RV cells by antiactin immunofluorescence staining, as previously described in other RV-infected cells, but its role in the disturbed phagocytosis of latex beads was not determined. Persistently RV-infected human RPE is an additional example of RV-associated secondary cellular dysfunction in the absence of cytopathic effects.

Activated retinitis pigmentosa peripheral lymphocytes adhere to and alter cultured human retinal pigment epithelial cells.

Interleukin-2 receptor (IL-2R) is an activation molecule that, when expressed on peripheral blood lymphocyte (PBL) membranes, indicates the secretion of IL-2 and initiation of an immune system activation cascade. Comparing the average of IL-2R expression in 34 patients with retinitis pigmentosa (RP) syndrome (561 +/- 282 cells/mm3; mean +/- standard deviation) with 35 age-matched normal subjects (194 +/- 39 cells/mm3), it was found that those with RP had greater numbers of IL-2R-positive cells (P less than 0.001). The increased amounts of IL-2R on PBL of 29 RP and the homotypic self-aggregation of RP PBL by phase and scanning electron microscopy led to the study of the interaction of RP PBL with cultured human postmortem retinal pigment epithelial cells (RPE). A direct correlation was found between the amount of IL-2R expression and the numbers of RP lymphocytes adhering to RPE monolayers. However, the adherence effect was not unique to RP syndrome but appeared to be a nonspecific result of lymphocyte activation. Greater adherence to RPE than normal also was observed in PBL from disease control subjects with elevated IL-2R values and in PBL stimulated by the mitogen, concanavalin A (Con-A). In addition, RPE monolayers were destroyed by Con-A-stimulated PBL that showed 95-98% IL-2R expression. Similar, but less serious effects, occurring in RPE cells after 1 wk's cocultivation with RP PBL, suggested that activated RP lymphocytes can be cytotoxic to RPE during prolonged contact. Because macrophage-like cells and class II major histocompatibility complex expression have been found in RP-affected retinas, immune-mediated cytopathologic effects may contribute to retinal degeneration in RP.

Antibody response to rubella virus antigen and structural proteins in retinitis pigmentosa.

Elevated serum ELISA IgG antibodies to rubella virus (RV) were found by three independent determinations in 41 (72%) of 57 adults with the retinal degeneration retinitis pigmentosa, while antibody responses to five other common neurotropic viruses were normal. However, these patients lacked clinical signs of active RV infection or known recent RV exposure, and 56 lacked IgM anti-RV antibody. Unusual relative percentages of IgG antibody to RV structural proteins compared with those of controls were found in patients' sera by radioimmunoprecipitation assay. For retinitis pigmentosa patients, percentage of RV envelope glycoprotein E1 antibody was similar to, of RV envelope glycoprotein E2 antibody was greater than, and of antibody to RV nucleocapsid C protein was lower than control percentages. Abnormal immunity to RV was also suggested by a lack of increased proliferation of lymphocytes to RV antigen despite elevated anti-RV antibody in patients with retinitis pigmentosa. Not associated with age or particular genetic pattern, these divergences from normal immunity suggest an unusual association between RV proteins and retinitis pigmentosa.

Systemic immunostimulation after retinal laser treatment in retinitis pigmentosa.

Systemic immunostimulation followed an experimental treatment trial of scatter argon laser photocoagulation directed to the retina of one eye of 10 patients with heredo-degenerative retinitis pigmentosa (RP). Significantly increased RP lymphocyte CD25, CD26, and CD4/CD26 activation epitope expressions over prelaser values and controls were found with a normalization of soluble interleukin-2 receptor secretion after laser treatment. Serum interferon-gamma was low both pre- and postlaser. Interestingly, when a panel of viral antibodies was tested, only those to rubella virus were elevated in the early postlaser period. The character of RP immunostimulation after laser-induced inflammation could be consistent with an antigenic stimulus from laser-released retinal proteins which might be of autoimmune or latent infectious origin. Enhanced immune responses may be a common but unrecognized sequellae of retinal laser.

Vasoactive intestinal peptide receptor expression on human lymphoblasts.

This study was designed to determine which (if any) subtypes of leukemic blasts express a functional receptor for vasoactive intestinal peptide (VIP). Blasts harvested from bone marrow of 38 newly diagnosed patients were classified as acute lymphocytic leukemia (CALLA + pre-B-cell leukemia, CALLA-, pre-B-cell leukemia, T-cell leukemia) or acute myeloid leukemia based on cytochemical and histochemical markers. Of the 32 patients with lymphocytic leukemia, 22 expressed the VIP receptor as evidenced by VIP-mediated activation of adenylate cyclase in cell homogenates. Binding of 125I-VIP to ALL cells correlated with the ability of VIP to activate adenylate cyclase. The VIP receptor was not identified in myeloid blasts from any of six patients. Further correlation of 125I-VIP binding and VIP-mediated stimulation of adenylate cyclase was demonstrated in transformed cell lines: a pre-B-cell line (Nalm 6) and a T-cell line (Molt 4b) exhibited high-affinity binding of 125I-VIP and VIP-mediated activation of adenylate cyclase, whereas neither the histiocytic line (U937) nor the myelocytic line (HL60) appeared to express the VIP receptor. These observations suggest a role for VIP in the proliferation or differentiation of human T and B lymphocytes.

Expression of Schwann cell and peripheral T-cell activation epitopes in hereditary motor and sensory neuropathy.

To evaluate possible immune-mediated mechanisms in hereditary motor and sensory neuropathy (HMSN-I, Charcot-Marie-Tooth syndrome), we examined class II major histocompatibility complex antigen expression (MHC-II, HLA-DR) in Schwann cells and peripheral lymphocyte T-cell (Ta1, CD26) activation in five unrelated adults with HMSN-I. Evidence of increased activation expression was found in both compartments but the pattern did not suggest a general state of hyperimmunity or appear related to clinical characteristics of HMSN. Significantly increased CD26+ T-cell activation and greater than normal fluctuation of values occurred intermittently in sequential tests of eight HMSN patients and at single time points in 24 others. The combined data, consistent with repeated stimulations of an immune reaction under normal feedback control, suggest that HMSN-I expresses some characteristics also found in autoimmune polyneuropathies.

The piebald-lethal murine strain: investigation of the cause of early death.

Forty-eight piebald-lethal (PL) mice with distal aganglionosis and 42 normal littermates (LM) were studied to determine the cause of early death. PL mice were noted to be smaller than their LM and to have normal albumin and immunoglobulin levels for the first 30 days of age. As PL mice aged, a significant decline in albumin with a concomitant rise in immunoglobulin levels was demonstratable. Systemic sepsis with enteric organisms was found in 10% of sacrificed PL mice and in 38% of spontaneously dying PL animals. Histologic examination of PL aganglionic and ganglionic colon demonstrated no evidence of enterocolitis. Ganglionic colon of PL mice contained a flattened, thinned mucosa. The early death of PL mice is related to generalized debilitation from prolonged distal colonic obstruction resulting in a decrease in immunologic integrity and an increased susceptibility to sepsis.

Identification of high affinity receptors for vasoactive intestinal peptide on human lymphocytes of B cell lineage.

Specific, high affinity receptors for vasoactive intestinal peptide (VIP) have been identified on a human pre-B cell line, Nalm 6, and on a human plasma cell line, Dakiki. The single class of high affinity sites exhibited a KD of 12.6 +/- 2.9 nM for VIP in Nalm 6 cells and 9.1 +/- 2.7 nM in Dakiki plasma cells. The homologous peptides, peptide histidine methionine (PHM), growth hormone releasing factor (GHRF), and secretin were all less effective than VIP in competitively inhibiting binding of 125I-VIP to Nalm 6 and Dakiki plasma membranes. The putative receptor was characterized as a 47-kDa protein using covalent cross-linking techniques and VIP stimulated adenylate cyclase in pre-B cells. Human lymphocytes of B cell lineage thus appear to express functional VIP receptors homologous to the receptor identified in T lymphoblasts, brain, pituitary, and intestine.

Serum fatty acid proportions in retinitis pigmentosa may be affected by a number of factors.

Variations in serum fatty acid (FA) proportions of 67 Retinitis pigmentosa patients suggested a consideration of other factors which might affect these values. Serum FA, particularly arachidonic acid, may be altered during immunoregulatory substance formation in addition to genetic and dietary controls. Parallel immune system studies of these patients showed FA patterns consistent with increased prostaglandin-mediated (PG) lymphocyte suppression in 27% and possible block of PG immunoregulation in another 37%. While differences found between total serum FA of RP patients and age-matched normals included lower 18:2 omega 6 and higher 22:6 omega 3, the dominant and recessive RP patients showed similar proportion. However, lower than normal 22:6 omega 3 was found in 7 Usher RP.

Immune alterations associated with T lymphocyte activation and regulation in retinitis pigmentosa patients.

Altered immunoregulation, suggested previously in the heredo-familial retinal degeneration, retinitis pigmentosa (RP), led us to examine cell-mediated immune responses in 58 RP patients who expressed either recessive or dominant inheritance. Increased absolute numbers of activated T-cells, quantitated by flow cytometry using the Ta1 epitope, were found in the peripheral blood of 60% of these RP patients. The unusual finding was equally distributed between dominant (16 of 25) and recessive (19 of 33) types of RP, suggesting an immune process present in both patterns of heredity. Additional altered lymphocyte immunoregulation was suggested in all RP by lymphocyte responses to stimulants modified by indomethacin or histamine in vitro. Although no clear association could be found between Tal expression and demographic factors including age, sex, years with RP symptoms, or percentage of life with RP disease, the significantly altered immunoregulatory responses in RP may be related to the pathogenesis of RP.

Activated T cells in type I Charcot-Marie-Tooth disease: evidence for immunologic heterogeneity.

Common recognized variability in the familial peripheral neuropathy, type I Charcot-Marie-Tooth disease (CMT I), led to an examination of cell-mediated immune responses in 23 CMT I patients. Increased numbers of activated T cells were found in the peripheral blood of 14 (61%) patients using fluorescent monoclonal Ta1 antibody as quantitated by flow cytometry. Altered immunoregulation was also suggested by increased levels of prostaglandin-mediated lymphocyte suppression. In the other nine CMT I patients, immune responses were normal. Lack of a relationship between Ta1 expression and CMT clinical symptoms, but with consistency within six CMT families, support the concept of immunologic heterogeneity in type I CMT with a possible genetic component.

Evidence of persistent viral infection in Menière's disease.

Aspects of humoral and cell-mediated immunity that might characterize the continuation of symptoms in 25 patients with chronic Meniere's disease were examined. We found significant elevations of both humoral and cellular immune responses to viral antigens of herpes simplex I, varicella-zoster, rubella, and cytomegalovirus. Serum immunoglobulins were quantitatively abnormal in 24 of 25 patients, without a consistent pattern. These immune responses may be linked to persistent viral infection in chronic Meniere's disease.

Role of the thymus in histiocytosis-X.

An increasing number of reports have demonstrated that patients with histiocytosis-X show significant morphologic changes in the thymus gland. The changes include severe dysplasia, dysmorphia, and severe nonspecific involution. These findings are present in all children with histiocytosis-X who die, but can be found even when the disease is limited to one bone and is not fatal.

Suppressor-cell dysfunction in children with histiocytosis-X.

Suppressor-cell activity of peripheral blood mononuclear cells were examined and lymphocyte subsets analyzed in children with histiocytosis-X and in healthy, age-matched subjects. Suppressor-cell function was assessed by two methods, the indomethacin stimulation of mitogen-activated cultures and the concanavalin A-inducible suppressor-cell assay. The results of these two assays indicate that children with active disease have significantly decreased suppressor-cell activity. Additionally, the percentage and absolute number of OKT8+ lymphocytes were decreased in children with active disease. Suppressor-cell activity and lymphocyte subsets returned to normal, baseline levels with disease remission. This study documents for the first time suppressor-cell dysfunction and supports previous investigations in which suppressor T lymphocytes are deficient in children with active disease. These findings may explain certain clinical manifestations seen in children with histiocytosis-X.

Progressive change in lymphocyte distribution and degree of hypergammaglobulinemia with age in children with hemophilia.

Fifty asymptomatic, pediatric hemophiliacs were examined for distribution of T-cell subsets, responsiveness to mitogen stimulation, interleukin-2 production, hypergammaglobulinemia, and the presence of antibody to virus including the human T-lymphotrophic virus type III (HTLV-III). Hemophilia A patients receiving factor VIII concentrate as replacement therapy had the most pronounced changes including decreased T4/T8 ratios and lower in vitro responsiveness to both phytohemagglutinin and pokeweed mitogen. Hemophilia A patients treated with cryoprecipitate and hemophilia B patients did not demonstrate these changes. Regardless of replacement therapy, hemophiliacs demonstrated a progressive decrease in the T4/T8 ratio and a progressive increase in the degree of IgG hypergammaglobulinemia as they aged. The amount of factor or cryoprecipitate or exposure to virus did not influence the T4/T8 ratio. These changes appear to be a result of chronic product exposure, which becomes more pronounced with increasing age.

HTLV-III status and abnormalities in T lymphocyte distribution in children with hemophilia A.

Children with hemophilia A are at risk for the acquired immunodeficiency syndrome (AIDS). Clinically asymptomatic hemophiliacs demonstrate many immune abnormalities that might represent exposure to the AIDS agent through blood products or be a natural reaction to their therapy. In this study, we examined lymphocyte subset distribution in children with hemophilia A who had been exposed to HTLV-III as determined by antibody seroconversion. Seroconversion to HTLV-III was confirmed using Western blot analysis. The lymphocyte subsets studied included T4+ and T8+ cells. The distribution of lymphocyte subsets in children with hemophilia A was independent of seroconversion to HTLV-III. Children with hemophilia A treated with commercial factor VIII concentrate had normal numbers of circulating T4+ lymphocytes and significantly increased numbers of circulating T8+ lymphocytes compared with their nontransfused age-matched counterparts. An increased number of T8+ lymphocytes was not observed, however, in children treated exclusively with cryoprecipitate. These results suggest that HTLV-III alone cannot account for changes in lymphocyte subsets in hemophiliacs. Higher antigenic protein loads in factor VIII concentrate or additional factors might account for the increased absolute numbers of T8+ lymphocytes and represent a natural response to therapy.