GLILD in CVID: Treating Lung Findings With No Agreed Standard
A retired park ranger's common variable immunodeficiency has quietly grown a second disease in his lungs. There is no established standard for treating GLILD — only a therapy with real evidence of benefit and real evidence of harm, drawn from the same small trial.
Walter B., 55, spent thirty-one years as a park ranger before retiring to a smaller cabin near the same forest he used to patrol, and still leads the occasional guided hike for the visitor center when they're short-staffed. His common variable immunodeficiency was diagnosed at age forty-four after two hospitalizations for pneumonia; he has been stable on monthly immunoglobulin replacement for eleven years, with no infections requiring hospitalization since, and no prior autoimmune or granulomatous complications of any kind noted on his annual surveillance visits. He has never smoked, has no occupational exposure history beyond ordinary outdoor forest work, and his only other chronic diagnosis is well-controlled hypertension.
A routine annual chest CT, ordered as part of his CVID surveillance rather than for any new symptom, showed bilateral ground-glass nodules and mediastinal lymphadenopathy; a transbronchial biopsy confirmed granulomatous-lymphocytic interstitial lung disease — a non-infectious complication that occurs in roughly eight to twenty percent of CVID patients and, left untreated, has been associated with survival cut roughly in half. His pulmonary function today is only mildly reduced — FVC at 82% of predicted, no symptoms he's noticed on his hikes — which is exactly what makes the next step contested rather than obvious. A 2017 British Lung Foundation and United Kingdom Primary Immunodeficiency Network consensus statement defined the condition formally but stopped short of recommending a specific treatment, since evidence-based guidelines don't yet exist for it. Chase et al., 2013, Journal of Clinical Immunology, first reported the rituximab-and-azathioprine combination in seven such patients with improved imaging and lung function and no significant chemotherapy-related complications; Verbsky et al., 2021, Journal of Allergy and Clinical Immunology, extended that experience to thirty-nine, where the imaging and pulmonary-function gains held — and the costs finally became visible at a size the smaller series could not show. Four of those thirty-nine had pneumonia during active treatment and two died after treatment completed. Nine relapsed, and five of the six who completed retreatment improved again, a pattern his pulmonologist reads as evidence the regimen works but doesn’t durably cure the underlying granulomatous process.
Treating a disease with no agreed standard behind it
Untreated GLILD has real mortality data behind it — survival estimated at roughly half of what it would otherwise be. Verbsky and colleagues treated thirty-nine CVID patients with this diagnosis using rituximab with an antimetabolite and found statistically significant improvement in HRCT scores, forced vital capacity, and FEV1. His imaging already shows disease; I don't think waiting for symptoms before treating is the safer read of that data.
I take the mortality data seriously, but that same Verbsky cohort had pneumonia during active treatment in four of thirty-nine patients and two deaths after treatment completed — in a population that, like Walter, was already immunodeficient before adding rituximab and azathioprine on top. He's asymptomatic with only mild functional impairment right now.
The mortality figure you're citing describes the natural history of untreated, typically already-symptomatic disease — it doesn't tell us what happens if we watch a mild, asymptomatic case closely instead of treating today.
There’s a middle position that wasn’t available when the combination became the reference standard. Tessarin et al., 2023, Journal of Clinical Immunology, gave first-line rituximab monotherapy to six CVID patients with GLILD and saw significant gains in total lung capacity and diffusing capacity with no severe adverse events — six patients, so I am not going to oversell it against thirty-nine, but it is the only published attempt to get the benefit without the antimetabolite sitting on top of an already-antibody-deficient patient. Given his mild, currently stable disease, starting rituximab alone with close serial monitoring — repeat HRCT and PFTs at three months — lets us treat the documented disease without necessarily paying the combination regimen's full toxicity cost up front.
Rituximab monotherapy was started, with repeat HRCT and pulmonary function testing scheduled at three months rather than waiting for the standard longer interval, given the disagreement about how much observation time was appropriate before escalating.
Not agreed: whether three months without improvement should trigger adding azathioprine immediately, as the pulmonologist would prefer, or whether a second course of rituximab alone should be tried first, as the immunologist argued, given how recently the monotherapy option entered the literature and how little head-to-head data exists to settle it either way.