Evaluation of Urinary Free Light Chains as a Marker of Severity of HIV Disease and Its Correlation with CD4 Count: A Pilot Study.

Human immunodeficiency virus (HIV) infection weakens immunity. Monitoring the immune status of the patient has become an important aspect of evaluating the progression of the disease and informing follow-up after treatment. Estimation of CD4 counts is quite costly and requires expertise in flow cytometry. In certain pathologies, free light chains (FLCs) are secreted in serum and urine and the magnitude can be used to monitor the severity, progression, and therapeutic monitoring of the disease. Urine as a specimen proves cost-effective and presents reduced risks during sample collection. The stability of light chains in urine at room temperature over extended periods simplifies the management of sample transportation as well. Hence, a pilot cross-sectional study was planned to evaluate the levels of urinary immunoglobulins in patients with HIV. The study was conducted at PGIMER, Dr. Ram Manohar Lohia Hospital (presently ABVIMS), New Delhi. Sixty-nine consecutive ART-naive HIV patients aged between 18 and 40 years and 69 age- and sex-matched healthy controls were included in the study. Urinary FLC kappa (κ) and lambda (λ) were measured using an immunoglobulin ELISA kit. Baseline urinary κ light chain levels were significantly higher in cases when compared with controls (p < .001) and were found to be increased with increasing WHO immunological classes (p < .001) and inversely related to CD4 cell count. However, no significant difference in mean urinary λ immunoglobulin light chain between cases and controls was found and no correlation with CD4 cell count or with stages of WHO immunological classification of HIV disease was observed. It is suggested that urinary free κ chain measurements combined with serum light chain measurements may be a useful marker in the follow-up and monitoring of response to therapies in patients with HIV where testing by flow cytometry is not available.