A 1 year old boy is brought to the OPD by his parents with complaints of inability to gain weight and chronic diarrhoea. He was growing well till the age of 6 months. After that, he staed to develop recurrent episodes of pneumonia. Family history is positive for similar symptoms in a maternal uncle. On examination, he is below the 3rd percentile for weight. Tonsils are absent. Stool is positive for Giardia. Which of the following is not true regarding his condition?