Pulmonary tuberculosis in a BCG vaccinated area: Relationship of disease severity with immunological and hematological parameters and drug resistance patterns

Clinical hematological and immunological parameters were studied in a group of 145 pulmonary patients with active tuberculosis, from a defined area of Karachi (Kharadar) belonging to the lower socioeconomic strata. Although clinical symptomatology could not differentiate the extent of lung involvement, a majority (69.6%) of the patients were diagnosed radiologically as having moderately advanced pulmonary disease. The peak number of patients were in their second decade of life. No differences were observed in the extent of disease based on age or gender. All hematological parameters for the group were in the normal ranges except for low levels of hemoglobin (9.58 ±1.55 SD; normal range 12-14 mg/dl) and a high ESR (90±31 SD; normal range 0-13 mm/hour). A negative correlation of PPD skin test induration (r=0.21, p=0.02), and a positive correlation of total white blood cell (r=0.20; p=0.015) was observed with the amount of lung tissue involved. The resistance amongst the strains for the four first line anti-tuberculosis agents was found to be: isoniazid = 27.4%; ethambutol = 14.5%; rifampicin = 11.29% and streptomycin = 12.9%. Multi-drug resistance to the most commonly prescribed combination (rifampicin and ethambutol) was 8.06%. Drug resistance patterns to individual drugs were comparable with resistance patterns observed in strains from greater Karachi at The Aga Khan Hospital during the same period. Such studies should provide improved rationale for patients diagnosis and treatment.