[Clinical features of X-linked agammaglobulinemia: analysis of 8 cases]

X-linked agammaglobulinemia (XLA), caused by mutations in Bruton's tyrosine kinase (BTK), is a common form of inherited antibody deficiency. There were very few case reports of this disease that were diagnosed only based on clinical findings in China. The purpose of this study was to evaluate the clinical features of 8 Chinese cases with XLA with BTK defect which were confirmed by flow cytometry and/or gene analysis.

Based on clinical findings, 8 suspected XLA patients were confirmed by detecting the expression of BTK by flow cytometry and/or gene analysis of BTK. The history and thorough physical examination and routine immunological evaluation of 8 cases were collected and reviewed.

The age of onset of all the 8 male patients were from 3 months to 3 years. The mean age at diagnosis was 6 years. Recurrent upper respiratory infection and pneumonia with fever were seen in all the patients. Nasopharynx infection was mainly contributed to upper respiratory infection. Very few or no otitis (1/8) and sinusitis (0/8) were involved. Polyarthritis without evidence of infection was common (3/8). Chronic diarrhea was documented during the first 2 years after the onset of the disease in 2 cases. Two of the patients suffered from meningitis one time each. Skin infection was not serious in two patients. Osteomyelitis occurred in one case, which occurred secondary to a trauma. One case had poliomyelitis-like disease that was considered to be related to polio vaccine. Only two cases had unconfirmed maternal family history of XLA. The prominent signs at diagnosis were dystrophia, growth and developmental retardation and markedly decreased or absent tonsils and lymph nodes. Concentration of all classes of serum immunoglobulins (Igs) and the number of B cells in the peripheral circulation were dramatically decreased. The ratio of CD4/CD8 in most of the patients (6/8) was markedly inverse.

The age at diagnosis of this reported group was older. Clinical symptoms displayed recurrent upper respiratory infection (nasopharynx infection but rare or no otitis or sinusitis) and pneumonia; polyarthritis was common. There were no confirmed family history of XLA. Most of the patients showed inverse ratios of CD4/CD8, the reason and potential significance are unclear.