good 's syndrome ( gs ) was first described by dr robert good in 1954 . good 's syndrome is a rare combination of thymoma and hypogammaglobulinemia , and features with few or absent b lymphocytes , cd4  +  t cell lymphopenia , and abnormal ratio of cd4  +  : cd8  +  t cell . an increased risk for infections in gs patients has been demonstrated by many case reports and reviews , but most infections are mild and can be managed at the outpatient department . good 's syndrome patients , when with moderate - to - severe infections , have to be hospitalized , but most of the hospitalized cases were described in a form of case report . the largest series of reported gs patients who were hospitalized for infections , only included 5 patients . another study by malphettes included 21 gs cases , but the paper did not state whether these patients were hospitalized for infections . this study presented a series of 12 gs patients hospitalized for infections in our hospital , and the clinical characteristics of this rare disease were illustrated . the medical files of patients who were hospitalized at peking union medical college hospital from january 2001 to july 2015 were searched for the discharge diagnosis of  good 's syndrome . the following data were retrieved for analysis : age , sex , clinical symptoms , laboratory findings , sites of infection , treatment , and outcomes . good 's syndrome is defined as following : ( 1 ) the presence of thymoma , confirmed by chest computed tomography and/or pathology ; and ( 2 ) hypogammaglobulinemia , defined as serum immunoglobulin g ( igg )  <  5  g / l , and/or immunoglobulin a ( iga )  <  0.7  g / l , and/or immunoglobulin m ( igm )  <  0.4 an infection was diagnosed when clinical manifestations indicated infection ( fever , cough , sputum , diarrhea , etc ) and corresponding pathogens were identified . the infection was also diagnosed if clinical manifestations for infections were unequivocal and the treatment aiming at the infection was effective even no pathogen was isolated . quantitative data were expressed as mean value    standard deviation , and qualitative results were described as percentage . a total of 14 patients with good 's syndrome were initially identified during this period . two patients were excluded because of no infection associated with their hospitalization , and 12 patients were eligible for this study . female patients accounted to three - fourths of 12 patients , and the patient age was ranged from 38 to 70 years ( mean age 56.7  +  10.1 years ) . clinical characteristics of good 's syndrome patients hospitalized for infections the thymoma was histologically confirmed in all patients and resected in 10 of them . the histological classification of thymoma was available for 7 patients : 3 with type ab , 3 patients with type a , and 1 patient with type b3 . b lymphocyte was significantly decreased in all patients , ranging from 0 to 9  cells/l ( 1.5  +  2.6  cells/l ) . cd4  +  t lymphocyte was also decreased ( 350.3  +  150.7 cells/l ) , and the ratio of cd4  +  : cd8 +  t lymphocyte was inversed in all patients ( 0.49  +  0.16 ) . serum igg , iga , and igm concentrations were all decreased , and the mean concentrations were 2.3  +  1.9 respiratory and intestinal tracts were the most common sites of infection , which occurred in 7 and 4 patients , respectively . encephalitis was diagnosed in 1 patient , and the site of infection in 1 patient was not specified . clinical symptoms were associated with the sites of infection . in patients with pulmonary infection , fever and cough were the most common clinical symptoms ( 7/7 ) , whereas diarrhea occurred in all patients with intestinal tract infection ( 4/4 ) . pathogens were identified in 10 patients including cytomegalovirus ( cmv ) in 5 patients , p. jirovecii and c. difficile in 2 patients , k. pneumonia in 2 patients , and s. pneumonia and h. influenza in 1 patient . eleven patients survived the infections , and only 1 died from severe pneumonia caused by p. jirovecii . to the best of our knowledge , this study presented the largest series of gs patients who were complicated by infections in a single center . we revealed several interesting findings : ( 1 ) infections were the most frequent cause for hospitalization of gs patients ; ( 2 ) respiratory and intestinal tracts were the most common sites of infection in hospitalized gs patients ; ( 3 ) opportunistic pathogens including cmv and p. jirovecii were commonly detected in hospitalized gs patients with infections . both our study and the literature showed that gs had a peak incidence of infection in the 5th and 6th decade . a systemic review demonstrated that 83.3% of gs patients caught infections . in this study , the infections were identified in 85.7% of the hospitalized gs patients , suggesting that infection was the most frequent cause for hospitalization of gs patients . this finding implies that gs should be suspected in a thymoma patient with recurrent infections . it has been reported that upper and lower respiratory tracts were the most common sites of infection in gs patients . upper respiratory tract infection and superficial fungal infection were precluded in this study because they generally would not be hospitalized . however , in gs patients who were regularly followed for a long period of time , as high as 85.7% of patients had at least 1 episode of pneumonia . a systemic review showed that diarrhea occurred in 31.8% of gs patients , but only 11.4% of patients were infectious . a higher percentage ( 58.3% ) of patients with diarrhea was detected in this study , and 33.3% of them had infectious diarrhea , demonstrating that the intestinal tract is another frequent site of infection in gs patients . bacteria , especially encapsulated bacteria including s. pneumonia , h. influenza , k. pneumonia , are the most important pathogens in infected gs patients . similar pathogens were identified in our study . recurrent bacterial infection in gs patients most likely reflects the igg deficiency , the part of problems with gs . different from common variable immunodeficiency ( cvid ) , cell - mediated immunodeficiency is a common manifestation in gs patients . cd4  +  t lymphocyte count was decreased in all patients and was < 400  cells/l in 58.3% of patients . although pathogenic bacterium is the most common pathogen in all gs patients , opportunistic pathogens associated with cell - mediated immunodeficiency including cmv ( 41.7% ) and p. jirovecii ( 16.7% ) , frequently caused opportunistic infections in hospitalized gs patients in this study . cmv often appeared to cause intestinal infection , and p. jirovecii led to pulmonary infection . thymoma features with autoimmunity , and 32.7% to > 50% of patients with thymoma exhibited autoimmune manifestations . pure red cell aplasia ( prca ) was the most common autoimmune complication associated with gs as shown by this cohort . leukopenia is also a common finding in gs patients , as was detected in 33.3% of patients in this study . although myasthenia gravis ( mg ) is a common comorbidity of thymoma , it is relatively rare in gs patients . in fact , none of our gs patients exhibited mg symptoms , which was consistent with another gs series . thymectomy is usually recommended in all patients with thymoma to prevent locally invasive growth and metastasis of tumor cells . however , the thymectomy is usually ineffective in improving immunodeficiency in gs patients , and it might worsen hypogammaglobulinemia in rare cases . immunoglobulin replacement has been used to maintain appropriate serum igg concentration to reduce infection . in this study , 83.3% of gs patients were infected and they received immunoglobulin replacement therapy in addition to antibiotics , resulting in clearance of infections in the majority of patients . therefore , we recommend immunoglobulin replacement as standard therapy in all hospitalized gs patients with infections . the only patient who died in this study was an old woman who developed prca . she was on corticosteroid and immunosuppressant therapy when she caught pulmonary infection with p. jirovecii . in our opinion , the immunosuppressive drugs contributed more to her death than gs itself . because gs is a rare disease , the value of this study is limited by relatively small number of enrolled patients . additionally , there are no definite criteria for hospitalization of gs patients , which may have resulted in biased findings by this study . nonetheless , this study excluded many mild or less important infections , which highlighted important infections in gs patients that should be managed timely and carefully . in conclusion , infections are a common manifestation in gs patients and are the most frequent cause for hospitalization . beside the pathogenic bacteria , we recommend a combination of antibiotics with immunoglobulin replacement as standard therapy for hospitalized gs patients with infections .