Introduction:
Human immunodeficiency virus (HIV) and tuberculosis (TB) are two main leading global causes of mortality and morbidity. TB and HIV increase progressive deterioration of immunological functions by speeding progression of one another.

Material and methods:
The present 5-year retrospective study was carried out in the Department of Pathology at a tertiary care hospital in South India. Study included clinico-pathological profile of 80 people living with HIV (PLHIV) and subsequently developed TB co-infection; their CD4+ counts done at the time of admission were examined.

Results:
The present study included 80 HIV-TB co-infected cases. The age of the patients ranged from 18 to 65 years. The mean CD4+ T lymphocyte count was 164.7 cells/μl. Pulmonary TB was diagnosed in 59 patients (73.8%), while extra-pulmonary TB was detected in 21 (26.2%) cases. Abdominal TB was the most common site among extra-pulmonary TB cases. Opportunistic infections (OIs) other than TB, included 2 cases with oral candidiasis and 1 case with central nervous system (CNS) toxoplasmosis. Two of the HIV-TB co-infected cases were subsequently diagnosed with primary CNS (n = 1) and retroperitoneal lymphoma (n = 1).

Conclusions:
In the present study, HIV-TB co-infection is more common in 25-50 years age group. Antiretroviral therapy has changed the nature of disease from fatal to chronic condition. OIs other than TB and neoplasms reported in our study included oral candidiasis, CNS toxoplasmosis, and lymphoma. PLHIV with low CD4+ count require close monitoring, adequate counselling, and further evaluation for atypical presentation of TB, OIs, and neoplasms to improve their outcomes.