Specific IgA antibody to Epstein-Barr viral capsid antigen: a better marker for screening nasopharyngeal carcinoma than EBV-DNA detection by polymerase chain reaction.

Nasopharyngeal carcinoma (NPC) is strongly associated with Epstein-Barr virus (EBV) infection. To assess whether EBV DNA detection by polymerase chain reaction (PCR) or presence of specific serum antibody to viral capsid antigen (VCA) was a better marker for screening NPC, nasopharyngeal tissues and blood samples from 58 NPC patients and 24 non-NPC patients (23 with laryngotracheal stenosis and 1 with chronic tonsillitis) were tested for the presence of EBV DNA and serum specific VCA antibodies, respectively. EBV DNA was detected in 56 (96.5%) of NPC patients and 15 (62.5%) of non-NPC controls, with predominantly EBV type A in both groups. On the other hand, specific VCA IgA antibody was detected in the majority of NPC patients: 52 (89.7%) while only 4 (16.7%) were detected in non-NPC controls. Therefore, specific VCA IgA antibody may serve as a better marker for screening NPC than EBV DNA detected by PCR.

Primary cryptococcal infection of the larynx in a patient with AIDS: a case report.

Primary laryngeal cryptococcosis was reported in a 42-year-old man with AIDS. The patient also had pulmonary tuberculosis and hydropneumothorax as a complication. Serological tests and/or cultures from blood, CSF, urine and pleural fluid were all negative for cryptococcus. He was successfully treated with oral fluconazole for 8 weeks to clear the infection and remained clear in the follow-up period 9 months after treatment.

Nasopharyngeal tuberculosis.

Nasopharyngeal tuberculosis used to be a common disease in the upper aerodigestive system. Before 1920, 1.4 and 6.5 per cent of all adenoids and tonsils removed from asymptomatic patients were infected by tuberculosis. After the introduction of antituberculous chemotherapy and BCG vaccination, this disease was considered uncommon and sporadic cases were reported in the medical literature. Recently, tuberculosis has begun to increase again due to the high global HIV-infected rate and antituberculous drug resistance among these people. To describe and highlight the clinical features of this condition, fifteen Thai patients (7 males and 8 females) from the Department of Otolaryngology, Siriraj Hospital, Bangkok, Thailand were reviewed. Cervical lymphadenopathy was the most common presenting symptom in our series (93.34%), 11 of them were classified as primary nasopharyngeal tuberculosis and most had abnormal nasopharyngeal findings by mirror examination except 2 cases. Although all had histopathological confirmation of nasopharyngeal tuberculosis, sometimes problems occur in the diagnosis between this disease and nasopharyngeal carcinoma, which are also common among Oriental people in many of their clinical similarities. Therefore routine nasopharyngeal biopsy is considered justified and diagnostic.

Risk factor for recurrence of nasopharyngeal cancer.

The nasopharyngeal carcinoma is the common disease in Thailand. Following the initial treatment, because of the locally advanced disease, there are some recurrences The purpose of the study was to determine the risk factors for the recurrence of nasopharyngeal carcinoma. We found that the undifferentiated carcinoma, microscopic residual disease and mild radiation reaction of the normal tissue were the risk factors for local recurrence (35.71%, 80% and 33.33%, respectively). Comparing with the squamous cell carcinoma, poorly diferentiated, no residual disease and marked radiation reaction of the normal tissue, which had lower incidence of local recurrence (7.69%, 25% and 25%, respectively).

Detection of Epstein-Barr virus DNA and HHV-6 DNA in tissue biopsies from patients with nasopharyngeal carcinoma by polymerase chain reaction.

A total of 34 tissue biopsies were collected from nasopharyngeal carcinoma (NPC) patients and 5 controls with non-NPC. Extracted DNA from tissue biopsies were analyzed for presence of specific gene sequences to EBV type A and type B, and HHV-6 by polymerase chain reaction (PCR). The different sequences of EBV type A and B were parts from the highly divergent forms of the EBV nuclear antigen 2 (EBNA 2). The PCR amplified products for EBNA 2A and EBNA 2B were 115 and 119 base pairs respectively whereas that of HHV-6 DNA was 776 base pairs. The results demonstrated that EBV DNA was detected in 32 of 34 cases (94.1%): 28 (82.3%) with type A, 2 (5.9%) with type B, and 2 (5.9%) with both types. EBV DNA of type A could be detected 1 (20%) of 5 controls. HHV-6 DNA was in 5 of 34 samples (14.7%) whereas HHV-6 DNA was not detectable in biopsy tissues from controls. The results show that in the NPC patient group, A type of EBV is predominant. Detection of HHV-6 DNA in patients group only might be resulted from reactivation of a latent infection or association with EBV-induction of NPC.

Prevalence of IgA specific antibodies to Epstein-Barr virus capsid and early antigens in nasopharyngeal carcinoma.

Ninety-one patients with nasopharyngeal carcinoma (NPC), and 164 age-matched healthy controls were tested for presence of IgA antibodies to Epstein-Barr virus capsid antigen (VCA) and early antigen (EA) in their sera by indirect ELISA using "EBViral DETECT" commercial test kit. IgA anti-VCA was found in 76 (83.5%) of NPC patients and 16 (9.8%) of the controls. Meanwhile, IgA anti-EA was found in 72 (79.1%) of NPC patients and 21 (12.8%) of the controls. In a parallel study by indirect immunofluorescence test (IIF), IgA anti-VCA was found in 77 of 91 (84.6%) NPC patients and 22 of 142 (15.5%) controls. The prevalence rates of anti-VCA as screened by ELISA and IIF were very similar suggesting that neither one of the two tests can be used alternatively depending on the purpose and facilities in each individual laboratory. IgA antibodies to VCA and EA were more prevalence in NPC patients than those in the controls, the finding which again supported the association between EBV and NPC as was suggested in many other reports.