Japanese cedar and cypress pollinosis updated: New allergens, cross-reactivity, and treatment

Pollen from many tree species in the Cupressaceae family is a well-known cause of seasonal allergic diseases worldwide. Japanese cedar pollinosis and Japanese cypress pollinosis, which are caused by pollen from Japanese cedar (Cryptomeria japonica) and Japanese cypress (Chamaecyparis obtusa), respectively, are the most prevalent seasonal allergic diseases in Japan. Recently, the novel major Japanese cypress allergen Cha o 3 and the homologous Japanese cedar allergen Cry j cellulase were identified, and it was shown, for the first time, that cellulase in plants is allergenic. Although the allergenic components of pollen from both species exhibit high amino acid sequence identity, their pollinosis responded differently to allergen-specific immunotherapy (ASIT) using a standardized extract of Japanese cedar pollen. Pharmacotherapy and ASIT for Japanese cedar and cypress pollinosis have advanced considerably in recent years. In particular, Japanese cedar ASIT has entered a new phase, primarily in response to the generation of updated efficacy data and the development of new formulations. In this review, we focus on both Japanese cypress and cedar pollinosis, and discuss the latest findings, newly identified causative allergens, and new treatments. To manage pollinosis symptoms during spring effectively, ASIT for both Japanese cedar and Japanese cypress pollen is considered necessary.

Immunological effects of sublingual immunotherapy with Japanese cedar pollen extract in patients with combined Japanese cedar and Japanese cypress pollinosis

Sublingual immunotherapy (SLIT) with Japanese cedar (JCe) pollinosis was expected to be effective for Japanese cypress (JCy) pollinosis. However, only a half of JCy pollinosis patients clinically improved. Therefore, we examined the immunological effect of SLIT for JCy pollinosis. Peripheral blood mononuclear cells (PBMCs) from patients with JCe and JCy pollinosis who did and did not receive SLIT were incubated with Cry j 1, Cha o 1 and Cha o 3 antigens. Basophil activation test (BAT) were performed. Production of IL-5 and IL-17 induced by antigens was inhibited in the SLIT group. Cry j 1-specific production of IL-10 was increased, and serum Cry j 1-specific IgE and -IgG4 were elevated. However, Cha o 1- or Cha o 3-specific production of IL-10 and specific IgG4 was not increased. Antigens-specific BAT did not decrease after SLIT. New SLIT with JCe and JCy is needed for patients with combined JCe and JCy pollinosis.

Identification of Cha o 3 homolog Cry j 4 from Cryptomeria japonica (Japanese cedar) pollen: Limitation of the present Japanese cedar-specific ASIT

BACKGROUND

About one-third of the Japanese population suffers from Japanese cedar pollinosis, which is frequently accompanied by Japanese cypress pollinosis. Recently, a novel major Japanese cypress pollen allergen, Cha o 3, was discovered. However, whether a Cha o 3 homolog is present in Japanese cedar pollen remains to be determined.

METHODS

Western blot analysis was performed using Cha o 3-specific antiserum. In addition, cloning of the gene encoding Cry j 4 was conducted using total cDNA from the male flower of Japanese cedar trees. Allergen potency and cross-reactivity were investigated using a T-cell proliferation assay, basophil activation test, and ImmunoCAP inhibition assay.

RESULTS

A low amount of Cha o 3 homolog protein was detected in Japanese cedar pollen extract. The deduced amino acid sequence of Cry j 4 showed 84% identity to that of Cha o 3. Cross-reactivity between Cry j 4 and Cha o 3 was observed at the T cell and IgE levels.

CONCLUSIONS

Cry j 4 was discovered as a counterpart allergen of Cha o 3 in Japanese cedar pollen, with a relationship similar to that between Cry j 1-Cha o 1 and Cry j 2-Cha o 2. Our findings also suggest that allergen-specific immunotherapy (ASIT) using Japanese cedar pollen extract does not induce adequate immune tolerance to Cha o 3 due to the low amount of Cry j 4 in Japanese cedar pollen. Therefore, ASIT using Cha o 3 or cypress pollen extract coupled with Japanese cedar pollen extract is required in order to optimally control allergy symptoms during Japanese cypress pollen season.

Airborne pollen and suicide mortality in Tokyo, 2001-2011

Prior research has indicated that pollen might be linked to suicide mortality although the few studies that have been undertaken to date have produced conflicting findings and been limited to Western settings. This study examined the association between the level of airborne pollen and suicide mortality in Tokyo, Japan in the period from 2001 to 2011. The daily number of suicide deaths was obtained from the Japanese Ministry of Health, Labour and Welfare, with pollen data being obtained from the Tokyo Metropolitan Institute of Public Health. A time-stratified case-crossover study was performed to examine the association between different levels of pollen concentration and suicide mortality. During the study period there were 5185 male and 2332 female suicides in the pollen season (February to April). For men there was no association between airborne pollen and suicide mortality. For women, compared to when there was no airborne pollen, the same-day (lag 0) pollen level of 30 to <100 grains per cm² was associated with an approximately 50% increase in the odds for suicide (e.g. 30 to <50 grains per cm²: odds ratio 1.574, 95% confidence interval 1.076-2.303, p=0.020). The estimates remained fairly stable after adjusting for air pollutants and after varying the cut-points that defined the pollen levels. Our results indicate that pollen is associated with female suicide mortality in Tokyo.