Diffuse Infiltrative Lymphocytosis Syndrome: A Patient Guide

Diffuse Infiltrative Lymphocytosis Syndrome (DILS) is a rare but distinct medical condition that occurs in some people living with HIV. It is fundamentally an immune system condition rather than a direct infection or a type of cancer. In DILS, the body produces an overabundance of CD8+ T-cells—a type of white blood cell that normally fights viruses—which then travel out of the bloodstream and crowd into various glands and organs ^[1][2]. While this “infiltration” can cause significant swelling and discomfort, understanding that it is thought to involve chronic immune activation to the virus is the first step toward managing it effectively ^[3].

What this means for my HIV: Having DILS does not mean that your HIV is uncontrolled or that you have AIDS. DILS is an inflammatory response, not cancer, and it does not mean you caused the condition. However, persistent, rapidly growing, painful, hard, or one-sided swelling still needs prompt assessment by your doctor.

The most recognizable signs of DILS involve the salivary glands, particularly the parotid glands located in the cheeks and jawline. When these glands become packed with immune cells, they swell, often on both sides of the face, and stop producing enough saliva. This leads to a set of symptoms known as sicca syndrome, which includes severe dry mouth and dry eyes ^[1][4]. While these symptoms can mirror other autoimmune diseases, DILS is unique because it is tied directly to how your immune system is responding to the HIV virus ^[3].

In some cases, this immune cell migration extends beyond the face and neck to internal organs such as the lungs, kidneys, or nerves. This “extraglandular” involvement can cause symptoms like a persistent dry cough, changes in kidney function, or numbness and tingling in the hands and feet ^[1][5]. However, these manifestations are uncommon and have broad alternative causes in people with HIV. Testing is symptom- and examination-directed; cough, urinary changes, or neuropathy should be evaluated for opportunistic infections or other causes rather than automatically attributed to DILS. Because DILS can affect multiple systems at once, your medical team will monitor your overall organ health alongside your HIV labs. Importantly, DILS can occur regardless of your CD4 count, meaning that even if your “helper” cells are at a healthy level, your CD8 cells may still be expanding ^[1][6].

The cornerstone of treating DILS is effectively managing the underlying HIV infection. For many patients, optimizing Antiretroviral Therapy (ART) to suppress the virus helps calm the immune system and cause the swelling to recede, though symptoms may require additional evaluation or treatment ^[1][3]. While the dryness and swelling can be frustrating and the diagnosis may feel heavy, ART often improves DILS. By focusing on consistent HIV care and working closely with your specialists, you can manage the inflammation and protect your long-term health and comfort ^[3][7].