What Causes Weight Loss In 6 Months Along With GI Symptoms, Abnormal Labs, And Recurrent Infections?

I have lost 22 kgs in last 6 months. CT enterography, PET CT, CT abdomen, US, Endoscopy, Colonoscopy done. Easophagitis Grade A, Weak LES, Chronic erosive inactive gastritis, distended stomach found. Alternating stomach burning (epigastric, mid abdomen, peri umblical burning, bloating & fullness, loose /bulky/no mucus & no blood/undigested food stools. Parameters outside range are - Igm low 39.5. Prothrombin time 5.89, homocysteine 21, Low leukocytes. Recurrent skin infections. Started with getting shingles. Had covid 4 months later.