Significantly higher cytokine and chemokine levels in patients with Japanese spotted fever than in those with Tsutsugamushi disease.

Tetracyclines are administered to cure Japanese spotted fever (JSF) and tsutsugamushi disease (TD). It is generally said that the clinical course of JSF is worse than that of TD despite antibiotic treatment. The precise mechanism underlying the more severe clinical course of JSF is not fully understood. We therefore examined whether the differential cytokine profile between these two infectious diseases contributes to the difference in clinical severity. The serum concentrations of various cytokines (tumor necrosis factor alpha [TNF-α], interleukin-6 [IL-6], and gamma interferon [IFN-γ]) and chemokines (IL-8, interferon-inducible protein 10 [IP-10], monocyte chemoattractant protein 1 [MCP-1], macrophage inflammatory protein 1α [MIP-1α], MIP-1ß, and eotaxin) were measured in 32 TD and 21 JSF patients. The results showed that serum levels of TNF-α in the acute phases of TD and JSF were significantly increased, with a higher concentration of TNF-α in patients with JSF (mean, 39.9 pg/ml) than in those with TD (mean, 13.8 pg/ml). Comparatively higher levels of other cytokines and chemokines (IL-6, IFN-γ, IL-8, IP-10, MCP-1, MIP-1α, and MIP-1ß) were also observed in the acute phase of JSF. The clinical severity score (3.67 ± 1.71) of JSF patients was higher than that of TD patients (1.47 ± 0.77). Our findings revealed that the cytokine and chemokine levels in the acute phase of JSF were significantly higher than those in the acute phase of TD. The differential cytokine levels may be related to the difference in clinical severity between JSF and TD.

Evaluation of Diagnostic Assay for Rickettsioses Using Duplex Real-Time PCR in Multiple Laboratories in Japan.

Tsutsugamushi disease and Japanese spotted fever are representative rickettsioses in Japan, and are caused by infection with Orientia tsutsugamushi and Rickettsia japonica, respectively. For molecular-based diagnosis, conventional PCR assays, which independently amplify respective rickettsial DNA, are usually used; however, this approach is time-consuming. Here, we describe a new duplex real-time PCR assay for the simultaneous detection of O. tsutsugamushi and spotted fever group rickettsiae, and its evaluation using several PCR conditions in 6 public health laboratories. The detection limit of the assay was estimated to be 102 copies and the sensitivity was almost identical to that of 3 conventional PCR methods. A total of 317 febrile patients were selected as clinically suspected or confirmed cases of rickettsioses. The detection efficiency of this assay for O. tsutsugamushi from blood or skin (eschar) specimens appeared to be almost the same as that of the conventional PCR method, even when performed in different laboratories, whereas the efficiency for spotted fever group rickettsiae tended to be higher than that of the 2 traditional double PCR assays. Our duplex real-time PCR is thus a powerful tool for the rapid diagnosis of rickettsioses, especially at the acute stage of infection.

A case of erythrokeratoderma variabilis: loosened gap junctions in the acanthotic epidermis.

A 15-year-old Japanese female without contributory personal or family medical history had demonstrated irregular, keratotic plaques in the lower extremities since infancy that had been gradually enlarging. The keratotic plaques showed partial erythematous change, which altered shape over a relatively short period, leaving pigmentation. The biopsy specimen taken from the erythematous, keratotic plaque showed typical church-spire-like papillomatosis with acanthosis, and thickening of granular and horny layers. Gene analysis targeting connexin 30.3 and 31, based on the diagnosis of erythrokeratoderma variabilis, did not demonstrate any abnormality of these genes. However, ultrastructural observation disclosed an increased amount of gap junctions, some of which showed four layers on high-powered electron microscopy, suggesting loosened connection of the plasma membrane of the keratinocytes through the gap junctions. This loosened gap junction structure was also observed in a case of lamellar ichthyosis, examined as a reference. The disturbed cell-to-cell interaction through latent damage to the gap junctions may be related to the keratotic changes of the epidermis in these skin diseases.