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IgG antibodies to a cleavage product of α-fodrin (120 kDa α-fodrin) have recently been identified as organ-specific autoantibodies in primary Sjögren’s syndrome. In this study, we examined seroreactivity of mothers and infants with neonatal lupus erythematosus (NLE) to a recombinant NH[sub 2]-terminal protein (120 kDa α-fodrin) of human α-fodrin. Serum samples were collected during the perinatal period in seven pregnancies of five mothers delivering offspring with NLE. Anti-120 kDa α-fodrin antibodies were identified by immunoblotting in six of seven perinatal maternal sera of offspring with NLE: one of two congenital heart block offspring and all five offspring with cutaneous NLE. These antibodies were placentally transmitted to infants. One of the five mothers had primary Sjögren’s syndrome, and four were asymptomatic. One asymptomatic mother did not demonstrate anti-120 kDa α-fodrin activity at the time of the first delivery of a congenital heart block infant, but was found to be positive at the time of subsequent delivery of a second child with cutaneous NLE. We propose that maternal antibodies to 120 kDa α-fodrin may be an additional serologic marker for the risk of NLE in anti-Ro/SS-A positive women. [ABSTRACT FROM AUTHOR]

SSA/Ro antigen is a soluble cellular component to which antibodies are frequently produced in patients with Sjögren's syndrome and systemic lupus erythematosus. Its exact location within the cell has yet to be determined. In this study we report the expression of SSA/Ro antigen in simian virus 40 (SV40)-transformed keratinocytes. The locations of SSA/Ro, U1RNP, and DNA antigens were studied by indirect immunofluorescence using monospecific antibodies. SSA/Ro antigen was detected in both the nucleus and cytoplasm of SV40-transformed keratinocytes tested with three monospecific sera. Primary cultured keratinocytes derived from adult human skin showed localized immunofluorescent staining within the nucleus. When Ca++ concentration of the medium was switched to 0.05 mM, these cells expressed cytoplasmic SSA/Ro antigens within 48 h. Depletion of the antibody activity with insolubilized human spleen extract abolished the staining. Surface expression of this antigen could not be detected in either primary or transformed cells. Localization of U1RNP and DNA was not altered. These results indicate that expression of SSA/Ro antigen in human keratinocytes is modulated by SV40 infection and that this antigen is expressed to a greater degree in cells that are less differentiated, transformed, or proliferating. [ABSTRACT FROM AUTHOR]

The expression of proliferating cell nuclear antigen (PCNA), also called cyclin, in human keratinocytes was examined by using the serum obtained from a SLE patient and a murine monoclonal antibody against PCNA/cyclin. In the normal epidermis, few of the nuclei were labeled with anti-PCNA/cyclin. This was in contrast to the positive nuclear staining seen in active lesions of psoriasis. In a primary culture of human keratinocytes growing as a monolayer, 20% - 30% of cells expressed PCNA/cyclin. SV4O-transformed human keratinocytes showed positive nuclear staining in about 40% of the cell population. In stratified keratinocytes cultured in a high Ca++ medium, PCNA/cyclin expression was decreased and only the cells in the basal and suprabasal layers showed positive staining. These results indicate that the expression of PCNA/cyclin correlates with the proliferating state in human keratinocytes and may not be associated with the mechanism of differentiation in keratinocytes. [ABSTRACT FROM AUTHOR]

Cryoproteins observed in patients with pemphigus have been shown to contain IgG, complement components, and other serum proteins. The IgG moiety possessed pemphigus antibody activity and contained kappa and lambda light chains. Cryoproteins appeared in the clinically active stage and disappeared subsequent to clinical improvement. These observations indicate that immune complexes may exist in the sera of patients with pemphigus. [ABSTRACT FROM AUTHOR]

Severe hypersensitivity to mosquito bites (HMB) is characterized by intense local skin reactions and systemic symptoms such as high fever, lymphadenopathy, and hepatosplenomegaly. Patients with HMB often have natural killer (NK) cell lymphocytosis associated with Epstein–Barr virus (EBV) infection. Here we investigated whether mosquito bites have any influence on the oncogenesis of EBV-infected NK cells. We examined six HMB patients with EBV-infected NK cell lymphocytosis. We first demonstrated that CD4 + T cells, but not NK cells, proliferated well in response to mosquito salivary gland extracts (SGE), especially to SGE of Aedes albopictus. When NK cells were cocultured with autologous CD4+ T cells stimulated by mosquito SGE, the expression of viral oncogene latent membrane protein 1 (LMP1) was remarkably enhanced. Next, we stimulated mononuclear cells of the patients with mosquito SGE, and NK cell counts were monitored for 28 d. The counts changed little from initial levels in the culture with mosquito SGE, whereas they decreased steadily in the culture without the extracts. Furthermore, we detected LMP1 mRNA in the skin lesion induced by mosquito SGE. These results suggest that mosquito bites can induce expression of the viral oncogene LMP1 in NK cells via mosquito antigen-specific CD4 + T cells, which is involved in the oncogenesis of NK cells in vivo. [ABSTRACT FROM AUTHOR]

We have recently developed a micropore ultraviolet irradiation technique. An isopore membrane filter with 3 μm diameter pores shields ultraviolet C radiation from cultured human fibroblasts, leading to partial irradiation within the cells with an average of about three exposed areas per nucleus. This study addressed the question of whether the spatial distribution of DNA damage within a cell nucleus is important in triggering ultraviolet-induced cytotoxicity. We have examined whether there are differences in cytotoxicity between partially ultraviolet-irradiated cells and uniformly irradiated cells after equal amounts of DNA damage were induced in the cell nuclei. We first determined DNA damage formation in normal human fibroblasts using an enzyme-linked immunosorbent assay. We found that 5 J per m2 ultraviolet irradiation produced an equivalent amount of cyclobutane pyrimidine dimers and (6–4) photoproducts per cell as 100 J per m2 with the membrane filter shield. At those doses, we found that both types of ultraviolet irradiation induced similar levels of cytotoxicity as assessed by a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. Both types of ultraviolet-irradiated cells also had similar cell-cycle distribution and apoptosis as measured by flow cytometry. Moreover, no significant differences in repair kinetics for either type of photolesion were observed between the two different ultraviolet treatments. Similar results were obtained in Cockayne syndrome cells that are defective in transcription-coupled nucleotide excision repair. Present results indicate that in the range of photoproducts studied, the spatial distribution of DNA damage within a cell is less important than the amount of damage in triggering ultraviolet-induced cytotoxicity. [ABSTRACT FROM AUTHOR]