Peripheral Erythrocytes Decrease upon Specific Respiratory Challenge with Grass Pollen Allergen in Sensitized Mice and in Human Subjects

Abstract

Background and AimsSpecific hyper-responsiveness towards an allergen and non-specific airway hyperreactivity both impair quality of life in patients with respiratory allergic diseases. We aimed to investigate cellular responses following specific and non-specific airway challenges locally and systemically in i) sensitized BALB/c mice challenged with grass pollen allergen Phl p 5, and in ii) grass pollen sensitized allergic rhinitis subjects undergoing specific airway challenge in the Vienna Challenge Chamber (VCC).Methods and ResultsBALB/c mice (n = 20) were intraperitoneally immunized with grass pollen allergen Phl p 5 and afterwards aerosol challenged with either the specific allergen Phl p 5 (n = 10) or the non-specific antigen ovalbumin (OVA) (n = 10). A protocol for inducing allergic asthma as well as allergic rhinitis, according to the united airway concept, was used. Both groups of exposed mice showed significantly reduced physical activity after airway challenge. Specific airway challenge further resulted in goblet cell hyperplasia, enhanced mucous secretion, intrapulmonary leukocyte infiltration and lymphoid follicle formation, associated with significant expression of IL-4, IL-5 and IL-13 in splenocytes and also partially in lung tissue. Concerning circulating blood cell dynamics, we observed a significant drop of erythrocyte counts, hemoglobin and hematocrit levels in both mouse groups, challenged with allergen or OVA. A significant decrease in circulating erythrocytes and hematocrit levels after airway challenges with grass pollen allergen was also found in grass pollen sensitized human rhinitis subjects (n = 42) at the VCC. The effects on peripheral leukocyte counts in mice and humans however were opposed, possibly due to the different primary inflammation sites.ConclusionOur data revealed that, besides significant leukocyte dynamics, particularly erythrocytes are involved in acute hypersensitivity reactions to respiratory allergens. A rapid recruitment of erythrocytes to the lungs to compensate for hypoxia is a possible explanation for these findings.

A case series: Association of anaphylaxis with a significant decrease in platelet levels and possible secondary risk of thrombosis

“…Transient sequestering and aggregation of platelets in the lungs and liver secondary to PAF has been reported in laboratory experiments with rabbits and other animals [2,17]. Murine studies have also studied platelets and erythrocytes response during anaphylaxis and have suggested possible participation via an allergic mechanism [18,19]. Specifically platelet's had a significant drop during anaphylaxis in the murine study by Krishnamurthy et al [18].…”

“…Murine studies have also studied platelets and erythrocytes response during anaphylaxis and have suggested possible participation via an allergic mechanism 18, 19. Specifically platelet's had a significant drop during anaphylaxis in the murine study by Krishnamurthy et al 18.…”

“…Murine studies have also studied platelets and erythrocytes response during anaphylaxis and have suggested possible participation via an allergic mechanism [18,19]. Specifically platelet's had a significant drop during anaphylaxis in the murine study by Krishnamurthy et al [18]. Murine studies involving horse serum induced anaphylaxis has also noted thrombocytopenia suggesting sequestering and activating of platelets [20].…”

Controlled Allergen Challenge Facilities and Their Unique Contributions to Allergic Rhinitis Research

“…This represents a novel basic mechanism that may contribute to the development of AR symptoms. However, the authors did not find agreement in the effects on peripheral leukocyte counts in mice and humans [95].…”

“…Researchers at the VCC examined circulating blood cell dynamics in an animal model and in human allergic participants exposed to grass pollen in the same study [95]. A significant drop in erythrocyte counts were found both in the murine model and human participants [95].…”