Cell-mediated immunity in nasopharyngeal carcinoma and allergic rhinitis: a controlled study

Ear, Nose & Throat Journal, May, 2007 by Hsien Teik Wong, Tengku A. Shahrizal, Narayanan Prepageran, Wye Keat Lim, Rajagopalan Raman

Abstract

We conducted a prospective study of 60 patients in a tertiary care referral center to ascertain the status of cell-mediated immunity as determined by delayed hypersensitivity reactions in patients with nasopharyngeal carcinoma (NPC) or allergic rhinitis. Delayed hypersensitivity as detected by Mantoux testing is generally accepted as a reflection of the level of cell-mediated immunoactivity--the less hypersensitivity reaction that occurs, the lower the level of immunoactivity is, and vice versa. Our study population was made up of three groups: 20 newly diagnosed patients with NPC (pretreatment), 20 age- and sex-matched patients with allergic rhinitis, and 20 matched controls without either disease. A negative Mantoux test (0- to 5-mm induration) was seen in 13 patients with NPC (65.0%), in 17 patients with allergic rhinitis (85.0%), and in 16 controls (80.0%); none of these differences was statistically significant. However, it is interesting that while the NPC group had the lowest percentage of negative Mantoux results overall, it had the highest percentage of patients who had no reaction at all (i.e., 0-mm induration); a complete absence of any reaction was seen in 7 of the 13 Mantoux-negative NPC patients (53.8%), compared with 2 of the 17 Mantoux-negative allergic rhinitis patients (11.8%) and 3 of the 16 Mantoux-negative controls (18.8%). An absence of a reaction generally indicates a very limited degree of cell-mediated immunoactivity. Therefore, we conclude that patients with NPC appear to have significantly less cell-mediated immunity than do patients with allergic rhinitis and normal controls; no statistically significant difference was noted between the latter two groups.

Introduction

Nasopharyngeal carcinoma (NPC) is a common malignancy among adults seen at the University Malaya Medical Center in Kuala Lumpur. It carries a poor prognosis if it is not detected early.

The role of immunology in the treatment of oncologic disease is well established. Cytotoxic T cells and natural killer T cells are part of the highly efficient defense mechanism that keeps ectopic malignant cells in check. However, the factors that regulate this mechanism are still largely unclear.

Some recent studies have suggested the possibility that patients with NPC experience a reduction in cell-mediated immunoactivity. (1) Moreover, NPC appears to have an inverse relationship with allergic rhinitis, and possible immunologic associations have been implied. The possibility of cross-reactivity between a type 1 hypersensitivity reaction (e.g., nasal allergy) and a type 4 hypersensitivity reaction (essentially cell-mediated immunoactivity) has been postulated. (2) If this hypothesis is true, the degree of cell-mediated immunity should be lower in patients with NPC than in patients with allergic rhinitis. T-lymphocyte dysregulation has also been shown to play a major role in airway allergy. (3)

The goal of this study was to ascertain the cell-mediated immune status of patients with NPC and to compare it with the status of patients with allergic rhinitis and normal controls.

Patients and methods

Candidates for this prospective study were recruited from the ENT clinic at our tertiary care referral center during 2003. Because a delayed hypersensitivity reaction to a previously sensitized antigen occurs, patients who had not been previously vaccinated with bacille Calmette-Guerin (BCG) were not eligible for this study. A negative BCG status was determined by a thorough history and by the absence of a BCG scar on the upper forearm. Also excluded were patients who were suspected of being immunocompromised and patients who had a history of pulmonary tuberculosis or who had been in close contact with such a patient.

We chose 60 patients--36 men and 24 women--to serve as our study population. Based on their pathology, patients were assigned to one of three age- and sex-matched groups; each group was made up of 12 men and 8 women, aged 32 to 63 years (mean: 41):

* One group was made up of patients with newly diagnosed and as-yet-untreated NPC. The presence of the cancer was confirmed by analysis of histologic specimens obtained from the postnasal space or the fossa of Rosenmuller.

* The second group was made up of patients who had a clinical diagnosis of allergic rhinitis.

* The control group was made up of subjects who had no history of allergic rhinitis or any malignancy.

After providing informed consent, all patients underwent a Mantoux test. Mantoux testing elicits a delayed hypersensitivity reaction to a previously sensitized antigen (a T-lymphocyte function), and it is generally accepted as a valid in vivo indicator of a patient's level of cell-mediated immunity. A complete absence of a response generally indicates an impairment of T-cell function, which reflects a low degree of cell-mediated immunoactivity. Mantoux testing was performed with tuberculin purified protein derivative (PPD) RT 23 SSI (Statens Serum Institut; Copenhagen). Each vial contained 1 ml of tuberculin PPD at a strength of 2 TU/0.1 ml.